Canadian Clinicaldrugtherapyf 27

KEY TERMS■ Chelating agent■ Electrolytes■ Enteral nutrition■ Fat-soluble

vitamins■ Hyperkalemia■ Hypokalemia■ Malabsorption■ Megaloblastic

anemia■ Megavitamins■ Parenteral nutrition■ Water-soluble

vitamins

OBJECTIVESAfter studying this chapter, you will be able to:

1. Assess patients for risk factors and manifestations of protein-calorie undernutrition.

2. Identify patients at risk for development of vitamin and/or mineral–electrolyte defi ciency or excess.

3. Describe the adverse effects associated with overdoses of vitamins.4. Discuss the rationale for administering vitamin K to newborns.5. Describe the signs, symptoms, and treatment of sodium, potassium,

magnesium, and chloride imbalances.6. Describe the signs, symptoms, and treatment of iron defi ciency anemia.7. Discuss the chelating agents used to remove excessive copper, iron, and

lead from body tissues.8. Apply nursing process skills to prevent, recognize, or treat nutritional

imbalances.9. Monitor laboratory reports that indicate nutritional status.

Nutritional Support Products, Vitamins, and Minerals–Electrolytes

C H A P T E R

57

Applying Your KnowledgeJane Farber is a 91-year-old woman who suffers from heart failure, osteoarthritis, and Parkinson’s

disease. Upon evaluation, you fi nd that Mrs. Farber is undernourished and slightly dehydrated.

Introduction

Water, carbohydrates, proteins, fats, vitamins, and minerals are required to promote or maintain health, to prevent illness, and to promote recovery from illness or injury. Water is required for cellular metabolism and excretion of metabolic waste products; 2,000 to 3,000 mL is needed daily. Proteins are structural and functional components of all body cells and tissues; the recommended amount for adults is 50 to 60 g daily. Carbohydrates and fats mainly provide energy for cellular metabolism. Energy is measured in kilocalories (kcal) per gram (g) of food oxidized in the body. Carbohydrates and proteins supply 4 kcal per g; fats supply 9 kcal per g.

Vitamins are required for normal body metabolism, growth, and development. They are com-ponents of enzyme systems that release energy from proteins, fats, and carbohydrates. They also are required for formation of red blood cells (RBCs), nerve cells, hormones, genetic material, and bone and other tissues. Minerals and electrolytes are essential constituents of bone, teeth, cell mem-branes, connective tissue, and many essential enzymes. They function to maintain fl uid, electrolyte, and acid–base balance; maintain osmotic pressure; maintain nerve and muscle function; assist in

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Chapter 57 Nutritional Support Products, Vitamins, and Minerals–Electrolytes ■ 903

contain 1 kcal per mL. Additional products are formulated for patients with special conditions (eg, renal or hepatic failure, malabsorption syndromes) or needs (eg, high protein, increased calories).

IV FluidsIV fl uids are used when oral or tube feedings are contraindi-cated. Most are nutritionally incomplete and used short term to supply fl uids and electrolytes. Dextrose or dextrose and sodium chloride solutions are often used. When nutrients must be pro-vided parenterally for more than a few days, a special paren-teral nutritional formula can be designed to meet all nutritional needs or to supplement other feeding methods.

Pancreatic EnzymesPancreatic enzymes (amylase, protease, lipase) are required for absorption of carbohydrates, protein, and fat. Pancrelipase (Cotazym, Ultrase, Pancrease, Viokase, others) is a commercial preparation used as replacement therapy in defi ciency states, including cystic fi brosis, chronic pancreatitis, pancreatectomy, and pancreatic obstruction. Dosage ranges from one to three capsules or tablets with each meal or snack.

VitaminsVitamins are obtained from foods or supplements. Although foods are considered the best source, studies indicate that most adults and children do not consume enough fruits, vegetables, cereal grains, dairy products, and other foods to consistently meet their vitamin requirements. In addition, some conditions increase requirements above the usual recommended amounts (eg, pregnancy, lactation, various illnesses).

Historically, the major concern about vitamins was suffi -cient intake to promote health and prevent defi ciency diseases. To this end, the Food and Nutrition Board of the National Academy of Sciences, an independent, non-governmental body, in association with Canadian and American scientists, established recommendations for daily vitamin intake (Dietary Reference Intakes [DRIs]; see Box 57-1). The DRIs provide

transfer of compounds across cell membranes; and infl uence the growth process.

For all of these nutrients, patients’ requirements vary widely, depending on age, sex, size, health or illness status, and other factors. This chapter discusses products to improve nutri-tional status in patients with defi ciency states and excess states of selected vitamins and mineral–electrolytes.

Nutritional Defi ciency States

Nurses encounter many patients who are unable to ingest, digest, absorb, or use suffi cient nutrients to improve or maintain health. Debilitating illnesses such as cancer; acquired immuno-defi ciency syndrome; and chronic lung, kidney, or cardiovascu-lar disorders often interfere with appetite and gastrointestinal (GI) function. Therapeutic drugs often cause anorexia, nau-sea, vomiting, diarrhea, or constipation. Nutritional defi cien-cies may impair the function of essentially every body organ. Signs and symptoms include unintended weight loss; increased susceptibility to infection; weakness and fatigability; impaired wound healing; impaired growth and development in children; edema; and decreased hemoglobin.

Nutritional Products

Various products are available to supplement or substitute for dietary intake. These may consist of liquid enteral formulas, intra-venous (IV) fl uids, pancreatic enzymes, vitamins, and minerals.

Liquid Enteral ProductsNumerous liquid enteral formulas are available over-the- counter (OTC) or in health care settings for oral or tube feedings. Many are nutritionally complete, except for water, when given in suffi cient amounts (eg, Ensure, Isocal, Sustacal, Resource). Additional water must be given to meet fl uid needs. Most oral products are available in a variety of fl avours and

Box 57-1 Dietary Reference Intakes

DRIs are the recommended amounts of vitamins (see Table 57-1) and some minerals (see Table 57-3). The current DRIs were established in 1997, 1998, and 2000 by the Food and Nutrition Board of the National Academy of Sciences in asso-ciation with Canadian and American scientists in an effort to streamline standards between countries, and are intended to replace the RDAs and RNIs (Canada) used since 1989. DRIs consist of four subtypes of nutrient recommendations as follows:

1. Estimated Average Requirement (EAR) is the amount esti-mated to provide adequate intake in 50% of healthy persons in a specifi c group.

2. Recommended Dietary Allowance (RDA) is the amount estimated to meet the needs of approximately 98% of

healthy children and adults in a specifi c age and gender group. The RDA is used to advise various groups about nutrient intake. It should be noted, however, that RDAs were established to prevent defi ciencies and that they were extrapolated from studies of healthy adults. Thus, they may not be appropriate for all groups, such as young children and older adults.

3. Adequate Intake (AI) is the amount thought to be suffi cient when there is not enough reliable, scientifi c information to estimate an average requirement. The AI is derived from data that show an average intake that appears to maintain health.

4. Tolerable Upper Intake Level (UL) is the maximum intake considered unlikely to pose a health risk in almost all

(continued on page 904)


904 ■ Section 9 Drugs Affecting the Digestive System

a set of dietary standards agreed upon by health professionals in both countries to replace the RNIs (Recommended Nutri-ent Intakes) in Canada and the RDAs (Recommended Dietary Allowances) in the United States.

Currently, concern extends to excessive vitamin intake, which may also cause disordered body metabolism and may be detrimental to health. Vitamin supplements are widely pro-moted to increase health and prevent or treat illness. However, the supplements can be harmful if overused. As a result, the DRIs include the maximum Tolerable Upper Intake Levels (ULs) of some vitamins. These amounts should not be exceeded.

Vitamins are classifi ed as fat-soluble (A, D, E, K) and water-soluble (B complex, C). Fat-soluble vitamins are absorbed from the intestine with dietary fat, and the absorption requires the presence of bile salts and pancreatic lipase. Vitamin D is discussed mainly in Chapter 25 because of its major role in bone metabolism. Vitamin defi ciencies occur with inadequate intake or disease processes that interfere with absorption or use of vitamins. Excess states occur with excessive intake of fat-soluble vitamins because these vitamins accumulate in the body. Excess states do not occur with dietary intake of water-soluble vitamins, but may occur with vitamin supplements that exceed recommended amounts. Vitamins are described further in Table 57-1, and recommended dosages of vitamin prepara-tions are listed in Table 57-2.

Vitamin SupplementsDietitians generally recommend people meet their vitamin needs through making choices from Canada’s Food Guide. Health care providers may prescribe vitamin supplements, but most supplements are self-prescribed. Because vitamins are essential nutrients, some people believe that large amounts (megadoses) promote health and provide other benefi cial effects. However, excessive intake may cause harmful effects, and “megavitamins” should never be self-prescribed. Addi-tional characteristics include the following:

■ Vitamins from supplements exert the same physiologic effects as those obtained from foods.

■ Most vitamin supplements do not require a prescription.

■ Vitamin products vary widely in number, type, and amount of specifi c ingredients.

■ Preparations should not contain more than recommended amounts of vitamin D, folic acid, and vitamin A.

■ Synthetic vitamins have the same structure and function as natural vitamins derived from plant and animal sources and are less expensive.

■ Multivitamin preparations often contain minerals as well. Large doses of all minerals are toxic.

■ Vitamins are often marketed in combination products with each other (eg, anti-oxidant vitamins) and with herbal prod-ucts (eg, B-complex vitamins with ginseng, for “energy”). Research studies are being done to determine the support for the use of such products.

■ Vitamin E contains four compounds of which alpha- tocopherol is the most active and is expressed as alpha- tocopherol equiv-alents (α-TE), as mg, and as International Units (IU). One α-TE is equivalent to 1 mg of active vitamin E. One IU of vitamin E is equal to 0.67 mg of α-TE.

Mineral–ElectrolytesThere are 22 minerals considered necessary for human nutri-tion. Some (calcium, phosphorus, sodium, potassium, magne-sium, chlorine, sulphur) are required in relatively large amounts. Calcium and phosphorus are discussed mainly in Chapter 25 because of their major roles in bone metabolism. Sulphur is a component of cellular proteins, several amino acids, B vitamins, insulin, and other essential body substances. No recommended intake has been established; it is obtained from protein foods.

Other minerals are required in small amounts and are often called trace elements. Eight trace elements (chromium, cobalt, copper, fl uoride, iodine, iron, selenium, and zinc) have relatively well defi ned roles in human nutrition. Others (man-ganese, molybdenum, nickel, silicon, tin, and vanadium) are present in many body tissues and may be necessary for normal growth, structure, and function of connective tissue. However, requirements are unknown and states of defi ciency or excess have not been identifi ed in humans.

healthy persons in a specifi ed group; it is not intended to be a recommended level of intake.

With vitamins, the ULs for adults (19–70 y and older) are D, 50 mg; E, 1,000 mg; C, 2,000 mg; folate, 1,000 mcg; niacin, 35 mg; and pyridoxine, 100 mg. With vitamins C and D and pyridoxine, the UL refers to the total intake from food, fortifi ed food, and supplements. With niacin and folate, the UL applies to synthetic forms obtained from supplements, fortifi ed foods, or a combination of the two. With vitamin E, the UL applies to any form of supplemental alpha-tocopherol. These ULs should not be exceeded.

There are inadequate data for establishing ULs for biotin, cyanocobalamin (B12), pantothenic acid, ribofl avin, and thia-mine. As a result, consuming more than the recommended amounts of these vitamins should generally be avoided.

With minerals, ULs have been established for calcium (2.5 g), phosphorus (3–4 g), magnesium (350 mg), fl uoride (10 mg), and selenium (400 mcg). The UL should not be exceeded for any mineral–electrolyte because all minerals are toxic in overdose. Except for magnesium, which is set for supple-ments only and excludes food and water sources, the stated UL amounts include those from both foods and supplements.

Box 57-1 Dietary Reference Intakes (continued)



VITAMIN/FUNCTION RDA FOOD SOURCES

SIGNS AND SYMPTOMS OF DEFICIENCY

SIGNS AND SYMPTOMS OF EXCESS

Fat-Soluble VitaminsVitamin A (retinol)Required for normal vision, growth, bone development, skin, and mucous membranes

RDAsa

Females: 14 y and older, 700 mcg; in pregnancy, 750–770 mcg; lactation, 1,200–1,300 mcg

Males: 14 y and older, 900 mcg

Children: 1–3 y, 300 mcg; 4–8 y, 400 mcg; 9–13 y, 600 mcg

Infants (AIs): 0–6 mo, 400 mcg; 6–12 mo, 500 mcg

Preformed vitamin A: liver, fortifi ed dairy products (eg, milk and margarine), and egg yolk

Carotenoids: turnip and collard greens, kale, spinach, carrots, sweet potatoes, squash, oranges, mangos, apricots, peaches, and cantaloupe

Night blindness; xerophthalmia, which may progress to corneal ulceration and blindness; changes in skin and mucous membranes that lead to skin lesions and infections, respiratory tract infections, and urinary calculi

Anorexia, vomiting, irritability, skin changes (itching, desquamation, dermatitis); pain in muscles, bones, and joints; gingivitis; enlargement of spleen and liver; increased intracranial pressure; and other neurologic signs

Congenital abnormalities in newborns whose mothers took excessive vitamin A during pregnancy

Acute toxicity, with increased intracranial pressure, bulging fontanels, and vomiting, may occur in infants who are given vitamin A

Vitamin EAnti-oxidant in preventing destruction of certain fats, including the lipid portion of cell membranes; may increase absorption, hepatic storage, and use of vitamin A

RDAsb

Females: 14 y and older, 15 mg; in pregnancy, 15 mg; lactation, 19 mg

Males: 14 y and older, 15 mg

Children: 1–3 y, 6 mg; 4–8 y, 7 mg; 9–13 y, 11 mg

Infants (AIs): 0–6 mo, 4 mg; 7–12 mo, 5 mg

Fortifi ed cereals, green leafy vegetables, egg yolk, milk fat, butter, meat, vegetable oils (eg, corn, saffl ower, soybean), wheat germ, and nuts (eg, almonds, pecans, sunfl ower seeds)

Defi ciency is rare Fatigue, nausea, headache, blurred vision, and diarrhea

Vitamin KEssential for normal blood clotting. Activates precursor proteins, found in the liver, into clotting factors II, VII, IX, and X

Females (AIs): 14–18 y, 75 mcg; 19–70 y and older, 90 mcg; in pregnancy, 75–90 mcg; lactation, 75–90 mcg

Males (AIs): 14–18 y, 75 mcg; 19–70 y and older, 120 mcg

Children (AIs): 1–3 y, 30 mcg; 4–8 y, 55 mcg; 9–13 y, 60 mcg

Infants (AIs): 0–6 mo, 2 mcg; 7–12 mo, 2.5 mcg

Dark green leafy vegetables (spinach, kale, cabbage, lettuce), caulifl ower, wheat bran, egg yolk, and liver

Abnormal bleeding (melena, hematemesis, hematuria, epistaxis, petechiae, ecchymoses, hypovolemic shock)

Clinical manifestations rarely occur. However, when vitamin K is given to someone who is receiving warfarin (Coumadin), the patient can be made “warfarin-resistant” for 2–3 weeks

Vitamin D (see Chap. 25)

Table 57-1 Vitamins







Water-Soluble VitaminsB-Complex BiotinEssential in fat and carbohydrate metabolism

Females (AIs): 14–18 y, 25 mcg; 19 y and older, 30 mcg; in pregnancy, 30 mcg; lactation, 35 mcg

Males (AIs): 14–18 y, 25 mcg; 19 y and older, 30 mcg

Children (AIs): 1–3 y, 8 mcg; 4–8 y, 12 mcg; 9–13 y, 20 mcg


Meat, poultry, fi sh (eg, salmon, trout, tuna), egg yolk, nuts, whole grains, cereals, legumes (garbanzo beans and lima beans), bananas, and potatoes

Anorexia, nausea, depression, muscle pain, and dermatitis

Not established

Cyanocobalamin (B12)Essential for normal metabolism of all body cells; normal RBCs; normal nerve cells; growth; and metabolism of carbohydrate, protein, and fat

Females: 14 y and older, 2.4 mcg; in pregnancy, 2.6 mcg; lactation, 2.8 mcg

Males: 14 y and older, 2.4 mcg

Children: 1–3 y, 0.9 mcg; 4–8 y, 1.2 mcg; 9–13 y, 1.8 mcg

Infants (AIs): 0–6 mo, 0.4 mcg; 7–12 mo, 0.5 mcg

Meat, eggs, fi sh (haddock, salmon, tuna), dairy products (cheese, milk, yogurt), and fortifi ed cereals

Pernicious anemia: decreased numbers of RBCs; large, immature RBCs; fatigue; and dyspnea

Severe defi ciency: leukopenia, infection, thrombocytopenia, cardiac dysrhythmias, and heart failure

Neurologic signs and symptoms: paraesthesias in hands and feet, unsteady gait, and depressed deep-tendon refl exes

Severe defi ciency: loss of memory; confusion; delusions; hallucinations; and psychosis may occur. Nerve damage may be irreversible

Not established

Folic acid (folate)Essential for normal metabolism of all body cells; normal RBCs; and growth

Females: 14 y and older, 400 mcg; in pregnancy, 600 mcg; lactation, 500 mcg

Males: 14 y and older, 400 mcg

Liver, kidney beans, fresh green vegetables (spinach, broccoli, asparagus), and fortifi ed grain products (eg, breads, cereals, rice)

Megaloblastic anemia that cannot be distinguished from the anemia produced by B12 defi ciency; impaired growth in children;

Not established

Table 57-1 Vitamins (continued)






Children: 1–3 y, 150 mcg; 4–8 y, 200 mcg; 9–13 y, 300 mcg


glossitis; and GI problems

Niacin (B3)Essential for glycolysis, fat synthesis, and tissue respiration. It functions as a coenzyme in many metabolic processes (after conversion to nicotinamide, the physiologically active form)

Females: 14 y and older, 14 mg; in pregnancy, 18 mg; lactation, 17 mg

Males: 14 y and older, 16 mg



Meat, poultry, fi sh (cod, halibut, salmon), peanuts, dairy products, eggs, whole grains, and enriched fl our and cereals

Pellagra: erythematous skin lesions, GI problems (stomatitis, glossitis, enteritis, diarrhea), and central nervous system problems (headache, dizziness, insomnia, depression, memory loss)

Severe defi ciency: delusions, hallucinations, and impairment of peripheral motor and sensory nerves

Flushing; pruritus; hyperglycemia; hyperuricemia; and increased liver enzymes

Pantothenic acid (B5)Essential for metabolism of carbohydrate, fat, and protein (eg, release of energy from carbohydrate; fatty acid metabolism; synthesis of cholesterol, steroid hormones, and phospholipids)

Females (AIs): 14 y and older, 5 mg; in pregnancy, 6 mg; lactation, 7 mg

Males (AIs): 14 y and older, 5 mg

Children (AIs): 1–3 y, 2 mg; 4–8 y, 3 mg; 9–13 y, 4 mg

Infants (AIs): 0–6 mo, 1.7 mg; 7–12 mo, 1.8 mg

Eggs, liver, salmon, yeast, caulifl ower, broccoli, lean beef, potatoes, tomatoes, whole-grain cereal and bread, avocados, and milk

No defi ciency state established

Not established

Pyridoxine (B6)A coenzyme in metabolism of carbohydrate, protein, and fat; required for formation of tryptophan and conversion of tryptophan to niacin; helps release glycogen from the liver and muscle tissue; functions in metabolism of the central nervous system; helps maintain cellular immunity

Females: 14–18 y, 1.2 mg; 19–50 y, 1.3 mg; 51–70 y and older, 1.5 mg; in pregnancy, 1.9 mg; lactation, 2.0 mg

Males: 14–50 y, 1.3 mg; 51–70 y and older, 1.7 mg

Children: 1–3 y, 0.5 mg; 4–8 y, 0.6 mg; 9–13 y, 1.0 mg


Yeast, wheat germ, liver and other glandular meats, fortifi ed whole grains and cereals, potatoes, poultry, fi sh (salmon, trout, tuna), legumes (garbanzo beans and lima beans), and bananas

Skin and mucous membrane lesions (seborrheic dermatitis, intertrigo, glossitis, stomatitis) and neurologic problems (convulsions, peripheral neuritis, mental depression)

Not established







Ribofl avin (B2)A coenzyme in metabolism; necessary for growth; may function in production of corticosteroids and RBCs and gluconeogenesis

Females: 14–18 y, 1.0 mg; 19 y and older, 1.1 mg; in pregnancy, 1.4 mg; lactation, 1.6 mg

Males: 14 y and older, 1.3 mg



Dairy products (milk, cheddar and cottage cheeses), meat, eggs, green leafy vegetables, mushrooms, salmon, organ meats (liver and kidney), and whole-grain and enriched cereals and breads

Glossitis, stomatitis, seborrheic dermatitis, eye disorders (burning, itching, lacrimation, photophobia, vascularization of the cornea)

Not established

Thiamine (B1)A coenzyme in carbohydrate metabolism; essential for energy production

Females: 14–18 y, 1.0 mg; 19 y and older, 1.1 mg; in pregnancy, 1.4 mg; lactation, 1.4 mg

Males: 14 y and older, 1.2 mg



Meat (especially pork), dried beans, whole- grain and enriched cereals and breads, peanuts, Brazil nuts, and brewer’s yeast

Mild defi ciency: fatigue, anorexia, retarded growth, mental depression, irritability, apathy, and lethargy

Severe defi ciency (beriberi): peripheral neuritis; personality disturbances; heart failure; edema; and Wernicke–Korsakoff syndrome in alcoholics

Not established

Vitamin C (ascorbic acid)Essential for formation of skin, ligaments, cartilage, bone, and teeth; required for wound healing and tissue repair, metabolism of iron and folic acid, synthesis of fats and proteins, preservation of blood vessel integrity, and resistance to infection

Females: 14–18 y, 65 mg; 19 y and older, 75 mg; in pregnancy, 80–85 mg; lactation, 115–120 mg

Males: 14–18 y, 75 mg; 19 y and older, 90 mg



Fruits (cantaloupe, kiwi fruit, mangos, papaya) and vegetables (sweet green, red, and yellow peppers), especially citrus fruits (oranges and grapefruit) and their juices

Mild defi ciency: irritability, malaise, arthralgia, and increased tendency to bleed

Severe defi ciency: scurvy and adverse effects on most body tissues (gingivitis; bleeding of gums, skin, joints, and other areas; disturbances of bone growth; anemia; and loosening of teeth). If not treated, coma and death may occur

Renal calculi

a RDAs for vitamin A are expressed in retinol activity equivalents (RAEs), which include both preformed vitamin A and carotenoids. 1 RAE = 1 mcg retinol or 12 mcg beta carotene.

b Vitamin E activity is expressed in milligrams of alpha-tocopherol equivalents (a-TE).

AIs, adequate intake—for all healthy infants, the AI is used and is based on estimated mean intakes of human milk; GI, gastrointestinal; RBCs, red blood cells; RDAs, recommended dietary allowances.

Table 57-1 Vitamins (continued)



Drugs at a Glance: Vitamin Drug PreparationsTable 57-2

GENERIC/TRADE NAME

ROUTES AND DOSAGE RANGES

COMMENTSAdults Children

FAT-SOLUBLE VITAMINSVitamin A (also called retinol)

Defi ciency, Children >8 y and adults, PO, IM 150,000 RE (500,000 IU) daily for 3 d, then 15,000 RE (50,000 IU) daily for 2 weeks, then 3,000–6,000 RE (10,000–20,000 IU) daily for another 2 mo

Kwashiorkor, Retinol 30 mg IM followed by intermittent oral therapy

Xerophthalmia (>1–8 y), 1,500–3,000 RE (5,000–10,000 IU)/kg for 5 d or until recovery

IM administration indicated when oral not feasible, as in anorexia, nausea, vomiting, pre-operative and post-operative conditions, or malabsorption syndromes

With xerophthalmia, vitamin E 40 IU should be co-administered to increase effectiveness of the retinol

Vitamin E PO 60–75 IU daily PO 15–30 IU daily

Vitamin K (Phytonadione, Mephyton)

If INR > 5 but <9 with no signifi cant bleeding give <5 mg PO, hold warfarin, give <5 mg PO if INR is still elevated, can give 1–2 mg PO; if INR > 9 with no signifi cant bleeding, hold warfarin and give 5–10 mg PO; if serious bleeding and elevated INRs, give 10 mg by slow IV infusion and repeat in 12 h as needed

Older children, same as adults

Newborns, prevention of hemorrhagic disease, IM 1 mg within 1 h after birth; if birth weight > 500 g and 0.5 mg if birth weight < 1,500 g; may be repeated after 2–3 weeks if the mother received anti-coagulant, anti-convulsant, anti-tubercular, or recent antibiotic drug therapy during pregnancy

Treatment of hemorrhagic disease, subcutaneous/IM 1 mg

For non-life-threatening bleeding, 0.5–2 mg subcutaneous or IV, if life-threatening bleeding, 5 mg IV over 10–20 min

Do not give IV; serious, anaphylaxis-like reactions have occurred

WATER-SOLUBLE VITAMINSB-COMPLEX VITAMINSCalcium pantothenate (B5) (Pantothenic acid, Penta/3b)

Total parenteral nutrition, IV 15 mg daily

Total parenteral nutrition, >11 y, IV 15 mg daily; 1–11 y, IV 5 mg daily

Defi ciency states seen only with severe, multiple B-complex defi ciency states

Cyanocobalamin (B12) PO 1,000–2,000 mcg daily, then 1,000 mcg daily

IM 30–100 mcg daily for 5–10 d, then 100–200 mcg monthly

IM, deep subcutaneous 100 mcg daily until total dose of 1–5 mg is given, then 60 mcg monthly

Oral drug, alone or in multivitamin preparations, is given for nutritional defi ciencies. Defi ciencies more common in the elderly

Folic acid (Apo-folic) Defi ciency, megaloblastic anemia, PO, Subcutaneous, IM, IV 0.25–1 mg daily until symptoms decrease and blood tests are normal, then maintenance dose of 0.4 mg daily

PO, subcutaneous, IM, IV up 0.25–1 mg daily until symptoms decrease and blood tests are normal, then a daily maintenance dose as follows: infants, 0.1 mg; <4 y, up to 0.3 mg; >4 y, 0.4 mg

Oral administration preferred unless severe intestinal malabsorption is present




Minerals occur in the body and foods mainly in ionic form. Ions are electrically charged particles. Metals (eg, sodium, potas-sium, calcium, magnesium) form positive ions or cations; non-metals (eg, chlorine, phosphorus, sulphur) form negative ions or anions. These cations and anions combine to form compounds that are physiologically inactive and electrically neutral. When placed in solution, such as a body fl uid, the components separate into electrically charged particles called electrolytes. At any given time, the body must maintain an equal number of positive and negative charges. Therefore, the ions constantly combine and separate to maintain electrical neutrality or electrolyte balance.

These electrolytes also maintain the acid–base balance of body fl uids. When foods are digested, they produce mineral res-idues that react chemically as acids or bases. Acids are usually

anions (eg, chloride, bicarbonate, sulphate, phosphate). Bases are usually cations (eg, sodium, potassium, calcium, magne-sium). If approximately equal amounts of cations and anions are present in the mineral residue, the residue is essentially neutral and the pH of body fl uids does not require adjustment. If there is an excess of cations (base), the body must draw on its anions (acid) to combine with the cations, render them physi-ologically inactive, and restore the normal pH of the blood. Excess cations combine with anions (eg, phosphate) and are excreted in the urine; excess anions combine with hydrogen ions or other cations and are excreted in the urine.

Mineral–electrolytes are obtained from foods or supple-ments. Although most minerals are supplied by a well- balanced diet, studies indicate that most adults and children do not ingest

Drugs at a Glance: Vitamin Drug Preparations (continued)Table 57-2

GENERIC/TRADE NAME


COMMENTSAdults Children

Niacin (nicotinic acid) (Niaspan)

Defi ciency, PO 50–100 mg daily

Pellagra, PO 300–500 mg daily in divided doses; maximum dose 500 mg daily

Dyslipidemia, PO 2–6 g daily, 50 mg TID initially, may double the dose every 5 d to 1.5–2 g/d (maximum dose, 4 g/d)

Niaspan:500 mg/d for 4 weeks, then 1,000 mg/d for 4 weeks, then increase up to 2,000 mg if necessary

100–300 mg daily in divided doses

To reduce fl ushing with larger doses, start with smaller doses and gradually increase them or administer ASA 325 mg 1 h prior to niacin

Pyridoxine (Vitamin B6) Defi ciency, PO, IM, IV 2–10 mg daily, once corrected, give 2–5 mg daily

Anemia, peripheral neuritis, 50–200 mg daily

5–25 mg daily for 3 weeks then 1.5–2.5 mg daily

Usually given with INH, an anti-tubercular drug, to prevent peripheral neuropathy

Ribofl avin (Vitamin B2) Defi ciency, PO 5–30 mg daily in divided doses

In total parenteral nutrition, IV 3–10 mg daily in divided doses

Defi ciency rarely occurs alone; more likely with other vitamin defi ciency states

Thiamine hydrochloride (Vitamin B1)

Vitathion-ATP

Defi ciency, PO 5–30 mg daily or in divided doses for 1 mo; IM 10–30 mg three times daily for 2 weeks, supplemented with 5–10 mg orally for 1 mo; IV 50–100 mg/d until able to take orally

10–50 mg daily in divided doses

Defi ciency is common in alcoholics

VITAMIN CVitamin C (ascorbic acid) Defi ciency, PO, IM, IV

100–250 mg once or twice daily for 2 weeks

100–300 mg in divided doses Excessive doses (eg, 2,000 mg or more daily) cause adverse effects and should be avoided

IM, intramuscular; IV, intravenous; PO, oral; RDA, recommended dietary allowance; TID, three times a day.



suffi cient dietary calcium and that iron defi ciency anemia is common in some populations. In addition, some conditions increase requirements (eg, pregnancy, lactation, various ill-nesses) and some drug–drug interactions decrease absorption or use of minerals.

As with vitamins, goals for daily mineral intake have been established as DRIs. Thus far, DRIs and ULs have been estab-lished for calcium, phosphorus, magnesium, iron, fl uoride, and selenium. The UL should not be exceeded for any mineral–electrolyte. Except for magnesium, which is set for supplements only and excludes food and water sources, the stated amounts include those from both foods and supplements. Mineral– electrolytes are described further in Table 57-3.

Mineral SupplementsMany people take mineral preparations as dietary supplements, usually in a multivitamin–mineral combination. Health care providers and patients should consider the following factors in relation to mineral supplements.

■ Nutritionists usually recommend dietary intake of nutrients rather than pharmaceutical supplements and emphasize that supplements do not compensate for an inadequate diet.

■ In general, recommended daily doses should not be exceeded because all minerals are toxic at high doses.

■ Multivitamin–mineral combinations recommended for age and gender groups contain different amounts of some

MINERAL/FUNCTION

RECOMMENDED LEVELS OF INTAKE FOOD SOURCES



Macro MineralsSodiumAssists in regulating osmotic pressure, water balance, conduction of electrical impulses in nerves and muscles, and electrolyte and acid–base balanceInfl uences permeability of cell membranes and assists in movement of substances across cell membranesParticipates in many intracellular chemical reactions

(AIs)

Females: 14–50 y, 1.5 g; 51–70 y, 1.3 g; 71 and older, 1.2 g; in pregnancy, 1.5 g; lactation, 1.5 g

Males: 14–50 y, 1.5 g; 51–70 y, 1.3 g; 71 and older, 1.2 g

Children: 1–3 y, 1 g; 4–8 y, 1.2 g; 9–12 y, 1.5 g

Infants: 0–6 mo, 0.12 g; 7–12 mo, 0.37 g

In most foods. Proteins contain large amounts, vegetables and cereals contain moderate to small amounts, fruits contain little or no sodium

Major source in the diet is table salt added to food in cooking, processing, or seasoning. One teaspoon contains 2.3 g of sodium

Water in some areas may contain signifi cant amounts of sodium

Serum sodium <35 mmol/L (mEq/L); anorexia, nausea, and vomiting; ataxia; confusion; delirium; hypotension and tachycardia; muscle tremors; oliguria and increased BUN; seizures; and weakness

Serum sodium >145 mmol/L (mEq/L); disorientation; dry skin and mucous membranes; fever; hyperactive refl exes; hypotension; muscle rigidity; tremors and spasms; irritability; cerebral hemorrhage; coma; oliguria, concentrated urine, and increased BUN

PotassiumWithin cells, helps maintain osmotic pressure, fl uid and electrolyte balance, and acid–base balance

In extracellular fl uid, is required for conduction of nerve impulses and contraction of skeletal and smooth muscle (especially important in myocardium)

Helps transport glucose into cells and is required for glycogen formation and storage

Required for synthesis of muscle proteins

(AIs)

Females: 14–70 y and older, 4.7 g; in pregnancy, 4.7 g; lactation, 5.1 g

Males: 14–70 y and older, 4.7 g

Children: 1–3 y, 3 g; 4–8 y, 3.8 g; 9–13 y, 4.5 g

Infants: 0–6 mo, 0.4 g; 7–12 mo, 0.7 g

Present in most foods, including meat, whole-grain breads or cereals, bananas, citrus fruits, tomatoes, and broccoli

Serum potassium <3.5 mmol/L (mEq/L); dysrhythmias and electrocardiographic changes; cardiac arrest; confusion; delirium; hyperglycemia; postural hypotension; muscle weakness; abdominal distention, constipation, paralytic ileus; polyuria, polydipsia, and nocturia

Prolonged defi ciency may increase serum creatinine and BUN

Serum potassium >5 mmol/L (mEq/L); muscle weakness; cardiotoxicity, with dysrhythmias or cardiac arrest

Cardiac effects are not usually severe until serum levels are 7 mmol/L (mEq/L) or above

Table 57-3 Minerals and Electrolytes




MINERAL/FUNCTION




MagnesiumRequired for conduction of nerve impulses and contraction of muscle (especially important in functions of cardiac and skeletal muscles)

Serves as a component of many enzymes

Essential for metabolism of carbohydrate and protein

Adults (RDAs):

Females 19–30 y, 310 mg; 31–70 y and older, 320 mg; in pregnancy, 350–400 mg; lactation, 310–360 mg.

Males 19–30 y, 400 mg; 31–70 y and older, 420 mg.

Upper Level (UL) or maximum intake from pharmaceutical preparations, 350 mg (does not include intake from food and water)

Children (RDAs): 1–3 y, 80 mg; 4–8 y, 130 mg; 9–13 y, 240 mg; 14–18 y, 410 mg


Present in many foods; diet that is adequate in other respects contains adequate magnesium. Good food sources include nuts, cereal grains, dark green vegetables, and seafoods

Serum magnesium < 1.5 mmol (mEq/L); ataxia; confusion; dizziness; irritability; muscle tremors, carpopedal spasm, nystagmus, generalized spasticity; seizures; tachycardia, hypotension, and premature atrial and ventricular beats

Serum magnesium > 2.5 mmol (mEq)/L; skeletal muscle weakness; cardiac dysrhythmias, hypotension; respiratory insuffi ciency; and coma

ChlorideHelps maintain osmotic pressure and electrolyte, acid–base, and water balance

Forms hydrochloric acid (HCl) in gastric mucosal cells

(AIs)

Females: 13–50 y, 2.3 g; 51–70 y, 2.0 g, 71 y and older, 1.8 g; in pregnancy and lactation, 2.3 g

Males: 13–50 y, 2.3 g; 51–70 y, 2.0 g; 71 y and older, 1.8 g

Children: 1–3 y, 1.5 g; 4–8 y, 1.9 g; 9–13 y, 2.3 g

Infants: 0–6 mo, 0.18 g; 7–12 mo, 0.57 g

Most dietary chloride is ingested as sodium chloride (NaCl), and foods high in sodium are also high in chloride

Serum chloride < 95 mmol/L (mEq/L); arterial blood pH > 7.45; dehydration; hypotension; low, shallow respirations; paraesthesias of face and extremities; and muscle spasms and tetany, which cannot be distinguished from the tetany produced by hypocalcemia

Serum chloride > 103 mmol/L (mEq/L); arterial blood pH < 7.35; increased rate and depth of respiration; lethargy, stupor, disorientation, and coma if acidosis is not treated

Trace ElementsChromiumAids glucose use by increasing effectiveness of insulin and facilitating transport of glucose across cell membrane

(AIs)

Females: 9–13 y, 21 mcg; 14–18 y, 24 mcg; 19–50 y, 25 mcg; 51–70 and older, 20 mcg; in pregnancy, 29–30 mcg; lactation, 44–45 mcg

Males: 9–13 y, 25 mcg; 14–50 y, 35 mcg; 51–70 y and older, 30 mcg

Children: 1–3 y, 11 mcg; 4–8 y, 15 mcg

Infants: 0–6 mo, 0.2 mcg; 7–12 mo, 5.5 mcg

Brewer’s yeast and whole-wheat products

Impaired glucose tolerance (hyperglycemia, glycosuria); impaired growth and reproduction; and decreased life span

Not established

Table 57-3 Minerals and Electrolytes (continued)



MINERAL/FUNCTION




CobaltA component of vitamin B12 that is required for normal function of all body cells and for maturation of RBCs

Approximately 1 mg in the form of vitamin B12

Animal foods, including liver, muscle meats, and shellfi sh. Fruits, vegetables, and cereals contain no cobalt as vitamin B12

Defi ciency of vitamin B12 produces pernicious anemia

Not established

CopperA component of many enzymes

Essential for correct functioning of the central nervous, cardiovascular, and skeletal systems

Important in formation of RBCs, apparently by regulating storage and release of iron for hemoglobin

(RDAs)

Females: 9–13 y, 700 mcg; 14–18 y, 890 mcg; 19–70 y and older, 900 mcg; in pregnancy, 1,000 mcg; lactation, 1,300 mcg

Males: 9–13 y, 700 mcg; 14–18 y, 890 mcg; 19 y and older, 900 mcg

Children: 1–3 y, 340 mcg; 4–8 y, 440 mcg


Many foods, including liver, shellfi sh, nuts, cereals, poultry, and dried fruits

Decreased serum levels; decreased iron absorption; anemia from impaired erythropoiesis; and leukopenia. Death can occur.

In infants, anemia, chronic malnutrition and diarrhea, or Menke’s syndrome (retarded growth and progressive mental deterioration) can occur

Increased serum levels; Wilson’s disease (a rare disorder characterized by accumulation of copper in brain, liver, and kidneys). Signs and symptoms vary according to affected organs

FluorideA component of tooth enamel

Strengthens bones

Adequate intake before ages 50–60 y may decrease osteoporosis and fractures during later years

Adults (AIs):

Females 19–70 y and older, 3 mg; in pregnancy and lactation, 3 mg.

Males 19–70 y and older, 4 mg.

Children (AIs): 1–3 y, 0.7 mg; 4–8 y, 1 mg; 9–13 y, 2 mg; 14–18 y, 3 mg


Beef, canned salmon, and eggs. Very little in milk, cereal grains, fruits, and vegetables. Fluoride content of foods depends on fl uoride content of the soil where they are grown

Dental caries and possibly a greater incidence of osteoporosis

Mottling of teeth and osteosclerosis

IodineEssential component of thyroid hormones

Adults (RDAs): males and females 14–51 y and older, 150 mcg; in pregnancy, 220 mcg; lactation, 290 mcg

Children: 1–8 y, 90 mcg; males 9–13 y, 120 mcg; females 9–13 y, 120 mcg

Infants: 0–6 mo, 110 mcg; 6–12 mo, 130 mcg

Seafood is the best source. In vegetables, iodine content varies with the amount of iodine in the soil where they are grown. In milk and eggs, content depends on the amount present in animal feed

Thyroid gland enlargement; possible hypothyroidism

Iodism, with coryza, edema, fever, conjunctivitis, lymphadenopathy, stomatitis, and vomiting




MINERAL/FUNCTION




IronEssential component of hemoglobin, myoglobin, and several enzymes: hemoglobin is required for transport and use of oxygen by body cells; myoglobin aids oxygen transport and use by muscle cells; enzymes are important for cellular metabolism

Adults (RDAs):

Females 19–50, 18 mg; 51 y and older, 8 mg; in pregnancy, 27 mg; lactation, 9–10 mg


Children: 1–3 y, 7 mg; 4–8 y, 10 mg; males 9–13 y, 8 mg; 14–18 y, 11 mg; females 9–13 y, 8 mg; 14–18 y, 15 mg

Infants (AIs): 0–6 mo, 0.27 mg; (RDA) 7–12 mo, 11 mg

Liver and other organ meats, lean meat, shellfi sh, dried beans and vegetables, egg yolks, dried fruits, molasses, whole-grain and enriched breads. Milk and milk products contain essentially no iron

Iron defi ciency anemia: with gradual development of anemia, minimal symptoms occur; with rapid development or severe anemia, dyspnea, fatigue, tachycardia, malaise, and drowsiness occur

Acute iron intoxication: vomiting, diarrhea, melena, abdominal pain, shock, convulsions, and metabolic acidosis. Death may occur within 24 h if treatment is not prompt

Chronic iron overload (hemochromatosis): cardiac dysrhythmias, heart failure, diabetes mellitus, bronze pigmentation of skin, liver enlargement, arthropathy, and others

SeleniumImportant for function of myocardium and probably other muscles

Adults (RDAs): males and females 19–70 y and older, 55 mcg; in pregnancy, 60 mcg; lactation, 70 mcg

Children (RDAs): 1–3 y, 20 mcg; 4–8 y, 30 mcg; 9–13 y, 40 mcg; 14–18 y, 55 mcg


Fish, meat, breads, and cereals

Defi ciency most likely with long-term IV therapy. Signs and symptoms include myocardial abnormalities and other muscle discomfort and weakness

Highly toxic in excessive amounts. Signs and symptoms include fatigue, peripheral neuropathy, nausea, diarrhea, and alopecia

ZincA component of many enzymes that are essential for normal metabolism (eg, carbonic anhydrase, lactic dehydrogenase, alkaline phosphatase)

Necessary for normal cell growth, synthesis of nucleic acids (RNA and DNA), and synthesis of carbohydrates and proteins

May be essential for use of vitamin A

Adults (RDAs):

Females 19–51 y and older, 8 mg; in pregnancy, 11–12 mg; lactation, 12–13 mg


Children: 1–3 y, 3 mg; 4–8 y, 5 mg; males 9–13 y, 8 mg; females 9–13 y, 8 mg

Infants (AIs): 0–6 mo, 2 mg; (RDA) 6–12 mo, 3 mg

Animal proteins, such as meat, liver, eggs, and seafood. Wheat germ is also a good source

Most evident in growing children and include impaired growth, hypogonadism in boys, anorexia, and sensory impairment (loss of taste and smell).

Also, if the patient has had surgery, wound healing may be delayed

Unlikely with dietary intake but may develop with excessive ingestion or inhalation of zinc. Ingestion may cause nausea, vomiting, and diarrhea; inhalation may cause vomiting, headache, and fever

AIs, adequate intakes—for all healthy infants, the AI is used and is based on estimated mean intakes of human milk; BUN, blood urea nitrogen; DRIs, dietary reference intakes; RBCs, red blood cells.

Table 57-3 Minerals and Electrolytes (continued)



minerals (eg, post-menopausal women need less iron than younger women). This should be considered in choosing a product.

■ Iron supplements other than those in multivitamin–mineral combinations are usually intended for temporary use in the presence of defi ciency or a period of increased need (eg, preg-nancy). They should not be taken otherwise because of the risk of accumulation and toxicity.

■ Although selenium is promoted as an anti-oxidant that decreases cardiovascular disease and cancer, there is limited evidence of such benefi ts and a selenium supplement is not recommended.

■ Sometimes mineral supplements are listed as the strength of the salt form of the mineral but they may contain a different (usually lesser) amount of the elemental form of the min-eral (eg, ferrous sulphate 300 mg = 60 mg elemental iron). Sometimes the elemental amount is listed on the side of the bottle label.

■ Although zinc is promoted for the treatment of the common cold and to promote wound healing, there is insuffi cient evi-dence to support such uses. With colds, zinc reportedly helps some people and does not help others. With wounds, zinc is reportedly benefi cial only if the patient has a zinc defi ciency. More studies are needed before supplemental zinc can be recommended for general use.

Agents Used in Mineral–Electrolyte Imbalances

Mineral–electrolyte imbalances include both defi ciency states and excess states. Most defi ciency states occur with inadequate intake or excessive losses (eg, vomiting, gastric suction, diar-rhea, overuse of laxatives). Most excess states occur with exces-sive intake or impaired renal excretion.

Several pharmacologic agents are used to prevent or treat mineral–electrolyte imbalances. Usually, neutral salts of miner-als (eg, potassium chloride) are used in defi ciency states, and non-mineral drug preparations are used in excess states. These agents are described below; routes and dosage ranges are listed in Table 57-4.

Cation Exchange ResinSodium polystyrene sulfonate (Kayexalate) is used to treat hyperkalemia. Given orally or rectally, the resin combines with potassium in the colon. Potassium is then eliminated from the body in the feces. Each gram of resin removes about 1 mmol (mEq) of potassium. Because the resin requires several hours to lower serum potassium levels, it may be used after other measures (eg, IV insulin and glucose infusions) have lowered serum levels. Insulin and glucose lower serum potassium levels by driving potassium into the cells; they do not remove potas-sium from the body. As the resin works in the intestinal tract, it releases sodium mole for mole with potassium uptake. Caution is advised when it is administered to patients with congestive

heart failure, severe hypertension, edema, or renal failure. Calcium polystyrene sulfonate (Resonium calcium) may be an alternate for these patients.

Chelating Agents (Metal Antagonists)Deferoxamine (Desferal) is used to remove excess iron from the body. When given orally within a few hours after oral ingestion of iron preparations, deferoxamine combines with the iron in the bowel lumen and prevents its absorption. When given par-enterally, it removes iron from storage sites (eg, ferritin, hemo-siderin) and combines with the iron to produce a water-soluble compound that can be excreted by the kidneys. The drug can remove 10 to 50 mg of iron per day. The urine becomes reddish brown from the iron content.

The major indication for use of deferoxamine is acute iron intoxication. The drug may also be used in chronic conditions characterized by accumulation of iron in tissues (eg, hemochro-matosis with blood transfusions, hemosiderosis due to certain hemolytic anemias).

Penicillamine (Cuprimine) chelates copper, zinc, mercury, and lead to form soluble complexes that are excreted in the urine. It is used mainly to remove excess copper in patients with Wilson’s disease, a rare condition characterized by accumulation of copper in vital organs. It also can be used prophylactically, before clinical manifestations occur, in patients in whom this hereditary condition is likely to develop. Penicillamine may be used to treat cystinuria, a hereditary metabolic disorder charac-terized by large amounts of cystine in the urine and renal calculi. It may be used in lead poisoning and in severe rheumatoid arthri-tis that does not respond to conventional treatment measures.

Iron PreparationsIron preparations are used to prevent or treat iron defi ciency anemia. For prevention, they are often given during periods of increased need (eg, childhood, pregnancy). Oral ferrous salts (sulphate, gluconate, fumarate) are preferred because they are well absorbed. Action starts in about 4 days, peaks in 7 to 10 days, and lasts 2 to 4 months. The drugs are not metabolized; a portion of a dose is lost daily in feces. Otherwise, the iron con-tent is recycled and its half-life is unknown. Sustained release or enteric-coated formulations are not as well absorbed as other preparations. Available ferrous salts differ in the amount of elemental iron they contain.

Adverse effects include nausea and other symptoms of GI irritation. Oral preparations also discolour feces, producing a black-green colour that may be mistaken for blood in the stool. Iron preparations are contraindicated in patients with peptic ulcer disease, infl ammatory intestinal disorders, anemias other than iron defi ciency anemia, multiple blood transfusions, hemochromatosis, and hemosiderosis.

Ferrous sulphate (Fer-In-Sol), which contains 20% elemental iron (ie, 60 mg per 300 mg tablet), is the proto-type and often the preparation of choice. Ferrous gluconate (Apo- ferrous gluconate) may be less irritating to GI mucosa and therefore better tolerated than ferrous sulphate. It contains 12% elemental iron (ie, 36 mg per 325 mg tablet). Ferrous



Drugs at a Glance: Individual Agents Used in Mineral–Electrolyte and Acid–Base Imbalances

Table 57-4

DRUGINDICATIONS FOR USE


Adults Children

CATION EXCHANGE RESINSodium polystyrene sulfonate (Kayexalate; PMS-sodium polystyrene sulfonate suspension)

Treatment of hyperkalemia

PO powder: 15 g in 100–200 mL of water or syrup, one to four times daily; suspension: 60 mL (15 g) one to four times daily

Rectally (retention enema) 30–50 g in 150–200 mL of water or 10% D/W q6h

Acute hyperkalemia: 1 g/kg body weight daily in divided doses

Maintenance therapy: 0.5 g/kg body weight daily in divided doses

CHELATING AGENTS (METAL ANTAGONISTS)Deferoxamine (Desferal)

Acute iron intoxication

Hemochromatosis due to blood transfusions

Hemosiderosis due to hemolytic anemia

IM 0.5–1 g initially given in one or two injections; maintenance dose depends on iron excretion rate, maximum dose, 6 g/24 h

Subcutaneous or IV 1–4 g (20–60 mg/kg depending on iron load) over 12 h

IV infusion (for patients in shock) (not to exceed 15 mg/kg/h), then reduce after 4–6 h so that total IV dose does not exceed 80 mg/kg up to a maximum dose of 6 g/24 h

IM 90 mg/kg followed by 45 mg/kg q 4–12 h up to a maximum of 6 g/24 h; a single injection should not exceed 1 g

Penicillamine (Cuprimine)

Wilson’s disease

Rheumatoid arthritis

Cystinuria

Wilson’s disease, 0.25–1.5 g, increased gradually if necessary, up to 2 g daily

Rheumatoid arthritis, PO 125–250 mg/d for 4 weeks, increased by 125–250 mg/d at 1- to 3-mo intervals, if necessary usual maintenance dose, 500–750 mg/d; maximum dose, 1,000–1,500 mg/d

Older children: same as adults

Children: Wilson’s disease, PO 250 mg daily, dissolved in fruit juice

IRON PREPARATIONSFerrous gluconate (Apo-ferrous gluconate)

Iron defi ciency anemia

PO 320–640 mg (40–80 mg elemental iron) three times daily

PO 100–300 mg (12.5–37.5 mg elemental iron) three times daily

Infants: PO 100 mg or 30 drops of elixir initially, gradually increased to 300 mg or 5 mL (15–37.5 mg elemental iron) of elixir daily, in divided doses

Infants and children: For severe defi ciency: 4–6 mg elemental iron/kg/d in three divided doses

For mild to moderate defi ciency: 3 mg elemental iron/kg/d single or divided doses

Ferrous sulphate (Fer-in-sol, Apo-ferrous sulphate)


PO 325 mg–1.2 g (60–240 mg elemental iron) daily in three or four divided doses

Syrup: each 5 mL = 150 mg (equivalent to 30 mg elemental iron)

Adults, 10–15 mL divided into three doses and give between meals with water or juice

Drops: each mL of liquid contains iron sulphate 75 mg (equivalent to 15 mg elemental iron)

Drops: 0–2 y, 5 mL daily divided into three doses given between meals, with water or juice

Syrup: 0–2 y, 2.5–5 mL; 2–6, 5 mL; 6–12 y, 5–12 mL; divided into three doses and given between meals with water or juice





Adults Children

Iron dextran injection (Dexiron, Infufer)


Dosage is calculated for individual patients according to hemoglobin and weight (see manufacturer’s literature). A small test dose is required before therapeutic doses are given

Dosage is calculated for individual patients according to hemoglobin and weight (see manufacturer’s literature). A small test dose is required before therapeutic doses are given

MAGNESIUM PREPARATIONS

Magnesium oxide

Magnesium hydroxide

Magnesium sulphate

Prevent or treat hypomagnesemia

Treat hypertension or convulsions associated with toxemia of pregnancy or acute nephritis in children

Hypomagnesemia, PO magnesium oxide 250–500 mg three to four times daily, milk of magnesia 5 mL four times daily, or a magnesium-containing antacid 15 mL three times daily; IM (magnesium sulphate) 1–2 g (2–4 mL of 50% solution) one to two times daily based on serum magnesium levels

Eclampsia, IM 1–2 g (2–4 mL of 50% solution) initially, then 1 g q30min until seizures stop

Convulsive seizures, IM 1 g (2 mL of 50% solution) repeated PRN

IV, do not exceed 150 mg/min (1.5 mL/min of a 10% solution, 3 mL/min of a 5% solution)

Convulsions, IM 20–40 mg/kg in a 20% solution; repeat as necessary

POTASSIUM PREPARATIONPotassium chloride (Apo-K; K-Lyte, Slow K, Micro-K, and others)

Prevent or treat hypokalemia

PO 20–40 mmol (mEq)/d

IV 40–100 mmol (mEq)/24 h, depending on serum potassium levels

Potassium chloride must be diluted in dextrose or NaCl IV solution for IV use

Maximum for serum K+ >2.5 mmol (mEq): diluted 40 mmol (mEq)/L, infused 10 mmol (mEq)/h to maximum dose of 200 mmol (mEq) in 24 h

Maximum for serum K+ <2.5 mmol (mEq): diluted 80 mmol (mEq)/L, infused 40 mmol (mEq)/h to maximum dose of 400 mmol (mEq) in 24 h

IV infusion 2–3 mmol (mEq)/kg or 40 mmol (mEq)/m2 daily

Adjust the amount of fl uids to body size

SODIUM PREPARATIONSodium chloride (NaCl) injection

Hyponatremia IV 1,500–3,000 mL of 0.45% or 0.9% solution/24 h depending on the patient’s fl uid needs; approximately 50 mL/h to keep IV lines open






Adults Children

ZINC PREPARATIONZinc sulphate (ADEKs Pediatric drops)

Prevent or treat zinc defi ciency

PO 25–50 mg elemental zinc (eg, zinc sulphate 110–220 mg) daily

Child: 4–10 y, one tablet daily; >10 y, two tablets daily

MULTIPLE MINERAL–ELECTROLYTE PREPARATIONSOral solutions (eg, Pedialyte)

IV solutions (eg, Normosol, Plasma-Lyte 148, Ringer’s solution)

Prevent or treat fl uid and electrolyte defi ciencies

IV 2,000–3,000 mL/24 h, depending on individual fl uid and electrolyte needs

IV, PO, amount individualized according to fl uid and electrolyte needs (ie, estimated fl uid loss), age and weight (see manufacturer’s literature)

IM, intramuscular; IV, intravenous; PO, oral; PRN, as needed.

fumarate (Palafer) contains 33% elemental iron (ie, 33 mg per 100 mg tablet). As with dietary iron, only a portion is absorbed from pharmaceutical preparations and relatively large doses are needed to supply the 10 to 15 mg needed daily by most adults and children. Co-administration with ascorbic acid (vitamin C) may increase absorption as iron is better absorbed in an acidic environment. Small amounts of iron are lost daily (about 0.5 to 1 mg) in urine, sweat, and sloughing of intestinal mucosal cells. Somewhat larger amounts (1 to 2 mg daily) are lost dur-ing menstruation. Thus, women of childbearing potential need larger amounts of iron than children, men, and postmenopausal women. Women who are pregnant have the greatest require-ment and usually need an iron supplement. Although most iron products are available OTC, their use should be discussed with a health care provider because of the toxicity that may occur with iron accumulation in body tissues.

Iron dextran injection (Dexiron, Infufer) is a parenteral form of iron useful in treating iron defi ciency anemia when oral supplements cannot be used. One millilitre contains 50 mg of elemental iron. Indications for use include peptic ulcer or infl ammatory bowel disease that is likely to be aggravated by oral iron preparations; the patient’s inability or unwillingness to take oral preparations; and a shortage of time for correcting the iron defi ciency (eg, late pregnancy or preoperative status). Contraindications include anemias not associated with iron defi ciency and patients with hypersensitivity to the drug (fatal anaphylactoid reactions have occurred).

The drug is usually given IV. Drug action has a slow onset and peaks in 1 to 2 weeks. Dosage is calculated according to hemoglobin level and weight. A small IV test dose should be given prior to a therapeutic dose. Emergency resuscitation equipment should be available, as fatal anaphylactic reactions have occurred with the use of IV iron. After the test dose is given without problem, at least 1 hour should elapse before the rest of the dose is administered.

Magnesium PreparationsMagnesium oxide or hydroxide may be given orally for mild hypomagnesemia in asymptomatic patients. Magnesium sulphate is given parenterally for moderate to severe hypomag-nesemia; convulsions associated with pregnancy; and prevention of hypomagnesemia in total parenteral nutrition. Therapeutic effects in these conditions are attributed to the drug’s depressant effects on the central nervous system and smooth, skeletal, and cardiac muscle. Oral magnesium salts may cause diarrhea; their uses as antacids and cathartics are discussed in Chapters 59 and 60, respectively.

Magnesium preparations are contraindicated in patients who have impaired renal function or who are comatose. Oral preparations of magnesium oxide or hydroxide act in 3 to 6 hours, are minimally absorbed systemically, and are excreted in urine. With parenteral magnesium sulphate, intramuscular (IM) injections act in 1 hour and last 3 to 4 hours; IV adminis-tration produces immediate action that lasts about 30 minutes. The products are excreted in urine.

Potassium PreparationsPotassium chloride (Slow-K, Apo-K, Micro-K, K-Dur) is usually the drug of choice for preventing or treating hypokalemia because defi ciencies of potassium and chloride often occur together. It may be prescribed for patients who are receiving potassium-depleting diuretics (eg, hydrochlorothiazide, furosemide); those who are receiving digoxin (hypokalemia increases risks of digoxin toxicity); and those who are receiving only IV fl uids because of surgical procedures, GI disease, or other conditions. Potassium chloride also may be used to replace chloride in hypochloremic metabolic alkalosis. It is contraindicated in patients with renal failure and in those receiving potassium-sparing diuretics, such as triamterene (Novo- Triamzide), spironolactone (Aldactone), or amiloride (Novamilor).

Drugs at a Glance: Individual Agents Used in Mineral–Electrolyte and Acid–Base Imbalances (continued)

Table 57-4



Potassium chloride can be given orally or IV. Oral prepara-tions are available in fl avoured powders, liquids, effervescent tablets, and controlled- or extended-release tablets or cap-sules. Most patients prefer tablets or capsules to liquids. These preparations act slowly and peak in 1 to 2 hours. IV prepara-tions act rapidly; IV potassium chloride must be well diluted before administration to prevent hyperkalemia, cardiotoxicity, and severe pain at the injection site. For patient safety, most hospitals restrict access to concentrated forms of potassium for injection. There are a variety of pre-mixed IV solutions con-taining a range of potassium concentrations (ie, 20 to 40 mmol [mEq per L] of potassium chloride) in several solutions (ie, D5W, normal saline, 2/3, 1/3) that do not require further dilution.

Dosage must be individualized according to serum potassium levels; the usual range is 10 to 60 mmol (mEq) in 24 hours.

Zinc PreparationsZinc sulphate (ADEKs Tablets) is available OTC in various forms and strengths (eg, tablets with 110 mg and capsules with 220 mg of zinc sulphate, equivalent to 25 or 50 mg of elemen-tal zinc). Zinc is also an ingredient in several vitamin–mineral combination products. Zinc preparations are given orally as a dietary supplement to prevent or treat zinc defi ciency. They have a slow onset of action and a delayed peak. They are metabolized in the liver and excreted in feces.

Multiple Mineral–Electrolyte PreparationsThere are numerous electrolyte solutions for IV use to maintain or replace electrolytes when the patient is unable to eat and drink.

Oral electrolyte solutions (eg, Pedialyte, Pedialyte Freezer Pops) contain several electrolytes and a small amount of dex-trose. They are used to supply maintenance amounts of fl uids and electrolytes when oral intake is restricted. They are espe-cially useful in children for the treatment of diarrhea and may prevent severe fl uid and electrolyte depletion. The amount given must be carefully calculated, prescribed, and adminis-tered to avoid excessive intake. Oral solutions should not be used in severe circumstances in which IV fl uid and electrolyte therapy is indicated and they should not be mixed with other electrolyte-containing fl uids, such as milk or fruit juices. In addi-tion, they must be cautiously used in impaired renal function.

Nursing Process

AssessmentAssess each patient for current or potential nutritional defi cien-cies. Some specifi c assessment factors include the following:

■ What are the usual eating patterns?■ Does the patient appear underweight? If so, assess for

contributing factors (eg, appetite; ability to obtain, cook,

or chew food). Calculate or estimate the body mass index (BMI); a BMI under 18.5 indicates underweight.

■ Does the patient have symptoms, disease processes, treat-ments, medications, or diagnostic tests that are likely to interfere with nutrition? For example, many illnesses and oral medications cause anorexia, nausea, vomiting, and diarrhea.

With vitamins, assessment factors include the following:

■ Defi ciency states are more common than excess states and people with other nutritional defi ciencies are likely to have vitamin defi ciencies as well.

■ Defi ciencies of water-soluble vitamins (B complex and C) are more common than those of fat-soluble vitamins.

■ Vitamin defi ciencies are usually multiple and signs and symptoms often overlap, especially with B-complex defi -ciencies.

■ Vitamin requirements are increased during infancy, preg-nancy, lactation, fever, hyperthyroidism, and many ill-nesses. Thus, a vitamin intake that is normally adequate may be inadequate in certain circumstances.

■ Vitamin defi ciencies are likely to occur in people who are poor, elderly, chronically or severely ill, or alcoholic.

■ Vitamin excess states are rarely caused by excessive dietary intake but may occur with use of vitamin drug prepara-tions, especially if megadoses are taken.

With mineral–electrolytes, assessment factors include the following:

■ Defi ciency states are more common than excess states unless a mineral–electrolyte supplement is being taken. However, defi ciencies and excesses may be equally harmful and both must be assessed.

■ Patients with other nutritional defi ciencies are likely to have mineral–electrolyte defi ciencies as well. Moreover, defi ciencies are likely to be multiple, with overlapping signs and symptoms.

■ Many drugs infl uence gains and losses of minerals and electrolytes, including diuretics and laxatives.

■ Minerals and electrolytes are lost with gastric suction, poly-uria, diarrhea, excessive perspiration, and other conditions.

Assess laboratory reports when available.

■ Check the complete blood count for decreased RBCs, hemoglobin, hematocrit, mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC). Reduced values may indicate a defi ciency ane-mia and further assessment is needed.

■ Check serum electrolyte reports for abnormal values. All major minerals can be measured in clinical laboratories. The ones usually measured are sodium, chloride, and potas-sium; carbon dioxide content, a measure of bicarbonate, is also assessed.

( Nursing Process continues on page 920)



Nursing Diagnoses■ Imbalanced nutrition: Less than body requirements related

to inadequate intake or impaired ability to digest nutrients■ Imbalanced nutrition: More than body requirements

related to excessive intake of pharmaceutical preparations of vitamins and minerals

■ Risk for injury related to complications of tube or IV feedings■ Risk for injury related to nutrient defi ciency or overdose■ Defi cient knowledge: Nutritional needs and sources of

nutrients

Planning/GoalsThe patient will

■ Improve nutritional status in relation to body needs■ Maintain fl uid and electrolyte balance■ Ingest appropriate amounts of vitamins and mineral–

electrolytes■ Experience no complications of enteral nutrition, includ-

ing aspiration, diarrhea, and infection■ Experience no complications of parenteral nutrition■ Describe the adverse effects of vitamins and minerals and

avoid if possible■ Take no mineral–electrolyte supplements unless recom-

mended by a health care provider■ Take mineral–electrolyte drugs as prescribed and have

appropriate laboratory tests to monitor response

Interventions■ Promote a well-balanced diet for all patients. Five to ten

daily servings of fruits and vegetables provide adequate vitamins unless the patient has increased requirements or conditions that interfere with absorption or use of vitamins. An oral multivitamin may benefi t some people, but it is not a substitute for an adequate diet. A diet that is adequate in protein and calories usually provides adequate minerals and electrolytes. Exceptions are calcium and iron, which often need to be encouraged in women and children.

■ Treat the symptoms or disorders which are likely to interfere with nutrition, such as pain, nausea, vomiting, or diarrhea.

■ Provide palatable supplements at appropriate times and encourage patients to take them for those who need increased protein-calorie intake.

■ Promote exercise and activity. For undernourished patients, this may increase appetite, improve digestion, and aid bowel elimination.

■ Weigh patients at regular intervals. Calculate or estimate BMI when indicated.

■ Monitor weight, fl uid intake, urine output, vital signs, blood glucose, serum electrolytes, and complete blood count daily or weekly, for those receiving parenteral

nutrition according to the patient’s status and whether he or she is hospitalized or at home.

■ Mineral supplements are recommended only for current or potential defi ciencies because all are toxic in excessive amounts.

■ For patients who have nasogastric tubes to suction, irrigate the tubes with isotonic sodium chloride solution. The use of tap water is contraindicated because it is hypotonic and would pull electrolytes into the stomach. Electrolytes are then lost in the aspirated and discarded stomach contents. For the same reason, only small amounts of ice chips or water are allowed per hour. Patients often request ice chips or water in larger amounts than desirable; the nurse must explain the reason for the restrictions.

■ Provide appropriate patient teaching regarding nutritional support products, vitamins, and minerals (see accompany-ing display).

■ Ensure food trays are within reach of the patient and containers are opened.

Evaluation■ Assess undernourished patients for quantity and quality of

nutrient intake, weight gain, and improvement in labora-tory tests of nutritional status (eg, serum proteins, blood sugar, electrolytes).

■ Assess children for quantity and quality of food intake and appropriate increases in height and weight.

■ Interview and assess for signs and symptoms of complica-tions of enteral and parenteral nutrition.

Principles of Therapy

Managing Nutritional Defi cienciesWhen possible, oral administration of liquid formulas, vita-mins, and minerals is preferred. With vitamin and mineral sup-plements, larger doses are needed to treat defi ciencies than are needed to prevent them. Treatment of defi ciency states should be cautious, to avoid excess states.

Enteral Nutrition: Oral and Tube FeedingsWhen the GI tract is functional but the patient cannot ingest enough food and fl uid, high-protein, high-calorie foods (eg, milkshakes) or nutritionally complete supplements (eg, Ensure) can be given with meals, between meals, and at bedtime. When oral feeding is contraindicated, tube feeding helps to maintain GI tract and immune system functioning. Guidelines for tube feedings include the following:

■ Several tubes and placement sites are available. For short-term use (about 4 weeks), a nasogastric tube may be used. For long-term feedings, a gastrostomy tube may be placed percutaneously or surgically. Nasointestinal tubes are



the small bowel cannot tolerate the larger volumes of inter-mittent feedings. Continuous feedings require an infusion pump for accurate control of the fl ow rate. Water can be given with, after, or between regular feedings and with med-ications, according to the patient’s fl uid needs.

■ A potential complication of tube feeding is aspiration of the formula into the lungs. This is more likely to occur with unconscious patients. The risk can be decreased by correctly positioning the patients, verifying tube placement, and giv-ing feedings slowly.

recommended for patients at risk of aspiration from gastric feedings or with gastric disorders. Except for gastrostomy tubes, the tubes should be soft and small-bore to decrease trauma.

■ When tube feedings are the patient’s only source of nutri-ents, they should be nutritionally complete and given in amounts calculated to provide adequate water, protein, cal-ories, vitamins, and minerals.

■ For feedings that enter the stomach, intermittent adminis-tration is often used. For feedings that enter the duodenum or jejunum, a continuous drip method is required because

Nutritional Support Products, Vitamins, and Minerals

General Considerations■ Nutrition is extremely important in promoting health and

recovery from illness. For people who are unable to take in enough nutrients because of poor appetite or illness, nutritional supplements can be very benefi cial in improv-ing nutritional status. For example, supplemental feedings can slow or stop weight loss; increase energy and feelings of well-being; and increase resistance to infection.

■ With oral or tube-feeding supplements, choose one or more that the patient is able and willing to take when possible.

■ With vitamins, supplements are often recommended because studies indicate that many adults and children do not ingest suffi cient dietary vitamins. Supplements are also usually needed by pregnant women and by people who smoke, ingest large amounts of alcohol, have impaired immune systems, or are elderly. When choosing a vitamin supplement, the following factors should be considered:■ Avoid large doses of vitamins. They will not promote

health, strength, or youth. In addition, excessive amounts of B vitamins and vitamin C are eliminated in urine and some can cause adverse effects (eg, large doses of vita-min C can cause kidney stones; niacin [B3] can cause stomach upset, fl ushing, skin rashes, itching, and aggrava-tion of asthma and gout; pyridoxine [B6] may cause numb-ness in limbs and diffi culty in walking). Excessive amounts of vitamins A, D, E, and K are stored in the body and often lead to toxic effects. For example, high doses of vitamin A can result in headaches; diarrhea; nausea; loss of appetite; dry, itching skin; and elevated blood calcium. Excessive doses during pregnancy may cause birth defects.

■ Although natural vitamins are advertised as being better than synthetic vitamins, there is no evidence to sup-port this claim. The two types are chemically identical and used in the same way by the human body. Natural vitamins are more expensive.

■ Sexually active women of childbearing potential need an adequate intake of folic acid to prevent severe birth defects in infants. To help prevent birth defects from folic acid defi ciency, Health Canada’s Food and Drug Regulations requires that folic acid be added to breads and cereal-grain products. This is estimated to add about 100 mcg of folic acid to the daily diet of most people. How-ever, the recommended daily intake for females 14 years and older is 400 mcg, which must be taken prior to becom-ing pregnant. Folic acid 1 mg tablets are available OTC.

■ Vitamins from supplements exert the same physiologic effects as those obtained from foods.

■ Multivitamin preparations often contain minerals as well, usually in smaller amounts than those recommended for daily intake. Large doses of minerals are toxic.

■ With minerals, a well-balanced diet contains all the minerals needed for health in most people. Exceptions are calcium and iron, which are often needed as a dietary sup-plement in women and children. Note that natural health products of chamomile, feverfew, and St. John’s wort may inhibit iron absorption. The safest action is to take mineral supplements only on a health care provider’s advice, in the amounts and for the length of time prescribed. All minerals are toxic when taken in excess. Additional considerations include■ Keep all mineral–electrolyte substances out of reach

of children to prevent accidental overdose. Acute iron intoxication is a common problem among young children and can be fatal. Also, supervise children in using fl uoride supplements (eg, remind them to spit out oral rinses and gels rather than swallow them).

■ Keep appointments with health care providers for periodic blood tests and other follow-up procedures when mineral–electrolyte supplements are prescribed (eg, potassium chloride). This helps prevent ingestion of excessive amounts.

■ Minerals are often contained in multivitamin prepara-tions, with percentages of the RDAs supplied. These amounts differ in various preparations and should be included in the estimations of daily intake.

■ Vitamin or mineral preparations may interact with prescription drugs; check with your doctor or pharmacist.

Self-Administration or Caregiver Administration■ For oral supplemental feedings, take or give at the preferred

time and temperature, when possible.■ For tube feedings

■ Use or give with the patient in a sitting position, if pos-sible, to decrease risks of choking and inhaling formula into the lungs.

■ Be sure the tube is placed correctly before each feeding. Ask a health care provider how to check placement with your type of tube.

( continued on page 922)



■ Be sure the solution is at room temperature. Cold formu-las may cause abdominal cramping.

■ Do not take or give >500 mL per feeding, including 60–90 mL of water for rinsing the tube. This helps avoid overfi lling the stomach and possible vomiting.

■ Take or give slowly, over approximately 30–60 min. Rapid administration may cause nausea and vomiting.

■ With continuous feedings, change containers and tubing daily. With intermittent feedings, rinse all equipment after each use, and change at least q24 h. Most tube-feeding for-mulas are milk based, and infection may occur if formulas become contaminated or equipment is not kept clean.

■ Ask a health care provider about the amount of water to take or give. Most people receiving 1,500–2,000 mL of tube feeding daily need approximately 1,000 mL or more of water daily. However, patients’ needs vary. Water can be mixed with the tube-feeding formula, given after the tube feeding, or given between feedings. Be sure to include the amount of water used for rinsing the tube in the total daily amount.

■ For giving medications by tube■ Give liquid preparations when available. When not avail-

able, some tablets may be crushed and some capsules may be emptied and mixed with 5–10 mL of water. Ask a health care provider which medications can safely be crushed or altered because some (eg, long-acting or enteric-coated) can be harmful if crushed.

■ Do not mix medications with the tube-feeding formula because some medications may not be absorbed.

■ Do not mix medications; give each one separately.■ Rinse the tube with water before and after each medica-

tion to get the medication through the tube and to keep the tube open.

■ With supplementary vitamins, preparations differ widely in amounts and types of vitamin content. The product should not contain more than recommended amounts of vitamin D and vitamin A because of possible adverse effects.

■ When choosing a vitamin supplement, compare the ingre-dients and costs. Store brands are as effective as and less expensive than name brands.

■ Vitamin C supplements are available in various dosages, often in multivitamin and other preparations sold as anti-oxidants. In 2000, the RDA was increased from 60 mg daily to 75 mg for adult women and 90 mg for adult men. Large doses (eg, 1,000 mg or more daily) may cause adverse effects and should be avoided. An adequate amount of vitamin C

can also be obtained by eating at least fi ve to ten servings of fruit and vegetables daily.

■ Take oral niacin preparations, except for timed-release forms, with or after meals or at bedtime to decrease stom-ach irritation. In addition, sit or lie down for approximately 30 min after taking a dose. Niacin causes blood vessels to dilate and may cause facial fl ushing, dizziness, and falls. Facial fl ushing can be decreased by taking 325 mg of acetyl-salicylic acid (ASA) 30–60 min before a dose of niacin. Itch-ing, tingling, and headache may also occur. These effects usually subside with continued use of niacin.

■ Swallow extended-release products whole; do not break, crush, or chew them. Breaking the product delivers the entire dose at once and may cause adverse effects.

■ Take prescribed vitamins as directed and for the appropri-ate time. In pernicious anemia, vitamin B12 injections must be taken for the remainder of life. In pregnancy and lacta-tion, vitamin supplements are usually taken only during this period of increased need.

■ Swallow vitamin E capsules whole; do not crush or chew.■ Take iron preparations with or after meals, with approxi-

mately 240 mL of fl uid, to prevent stomach upset. Do not take iron with coffee or other caffeine-containing beverages because caffeine decreases absorption (take iron and caf-feine preparations at least 2 h apart). Do not crush or chew slow-release tablets or capsules. With liquid preparations, dilute with water or juice, drink through a straw, and rinse the mouth afterward to avoid staining the teeth. Expect that stools will be dark green or black.

■ With potassium preparations, mix oral solutions or efferves-cent tablets with at least 120 mL of water or juice to improve the taste, dilute the drug, and decrease gastric irritation. Do not crush or chew slow-release preparations. Ensure tablets or capsules are taken with adequate amounts of fl uid so they do not stick in the esophagus. Take after meals ini-tially to decrease gastric irritation. If no nausea, vomiting, or other problems occur, the drug can be tried before meals because it is better absorbed from an empty stomach. Do not stop taking the medication without notifying the physician who prescribed it, especially if taking digoxin or diuretics. Excessive amounts should also be avoided. Do not use salt substitutes unless they are recommended by a health care provider; they contain potassium chloride and may result in excessive intake. Serious problems may develop from either high or low levels of potassium in the blood.

Parenteral Nutrition: IV FeedingsParenteral feedings are indicated when the GI tract is non-functional, when nutritional needs cannot be met by enteral feedings, or when enteral feedings would aggravate conditions such as infl ammatory bowel diseases or pancreatitis.

Short-Term IV NutritionFor short-term use (eg, 3 to 5 days), the goal is to provide adequate amounts of fl uids and electrolytes and enough car-bohydrate to minimize oxidation of body protein and fat for energy. The choice of specifi c solution depends on individual needs, but it should contain at least 5% dextrose. A frequently

used solution is 5% dextrose in 0.22% sodium chloride, 2,000 to 3,000 mL in 24 hours (provides approximately 170 kcal per L, water, sodium, and chloride). Potassium chloride is often added, and vitamins may be added. These solutions are nutri-tionally inadequate.

Long-Term IV NutritionFor long-term use (weeks to months), the goal is to provide all nutrients required for normal body functioning, including tissue growth and repair. Basic solutions provide water, carbohydrate, protein, vitamins, and minerals; fat emulsions (eg, Intralipid) are usually given separately to provide additional calories

Nutritional Support Products, Vitamins, and Minerals (continued)



until serum prothrombin activity returns to a normal range. In obstructive jaundice, bile salts must be given at the same time as oral vitamin K, or vitamin K must be given parenterally. In malabsorption syndromes or diarrhea, parenteral administra-tion is probably necessary. A single dose of vitamin K may be suffi cient.

With severe bleeding, vitamin K may be given IV but must be given very slowly to decrease risks of hypotension and shock. Even with IV vitamin K, however, therapeutic effects do not occur for at least 4 hours. For more rapid control of bleeding, transfusions of plasma or whole blood are needed.

B-Complex DisordersWith B-complex vitamins, most defi ciencies are multiple rather than single and treatment consists of increasing intake of foods containing B-complex vitamins (many foods, includ-ing meat, vegetables, and cereal grains) or giving multivitamin preparations. If a single defi ciency seems predominant, that vitamin may be given alone or in addition to a multivita-min preparation. For example, folic acid defi ciency may occur with inadequate dietary intake and intestinal disorders that inhibit absorption. In addition, folic acid is depleted by alco-hol and several medications, including antibiotics containing trimethoprim (eg, Bactrim), phenytoin, methotrexate, and oral contraceptives. Thiamine defi ciency is common in alcohol-ics because of inadequate dietary intake and the use of large amounts of thiamine to metabolize ethanol.

Anemias Associated With B-Complex Vitamin Defi cienciesOne type of anemia occurs with pyridoxine defi ciency and is relieved by administration of pyridoxine. Another type, called megaloblastic anemias (because they are characterized by abnor-mally large, immature RBCs), occurs with defi ciency of folic acid or vitamin B12. If megaloblastic anemia is severe, treat-ment is usually instituted with both folic acid and vitamin B12.

In pernicious anemia, vitamin B12 must be given by injec-tion because oral forms are not absorbed from the GI tract. The injections must be continued for life. Vitamin B12 is also given to prevent pernicious anemia in patients who are strict vegetarians, who have had gastrectomy, or who have chronic small bowel disease. Although folic acid relieves hematologic disorders of pernicious anemia, giving folic acid alone allows continued neurologic deterioration. Thus, an accurate diagno-sis is required.

In other megaloblastic anemias, vitamin B12 or folic acid is indicated. Although both of these are included in many mul-tivitamin preparations, they usually must be given separately for therapeutic purposes. With vitamin B12, doses in excess of 100 mcg are rapidly excreted in urine. With folic acid, doses in excess of 1 mg are excreted in the urine.

Ascorbic Acid (Vitamin C) DisordersTreatment of vitamin C defi ciency involves increased intake of vitamin C from dietary (eg, fruits and vegetables) or pharma-ceutical sources. Vitamin C is available alone for oral, IM, or IV administration. It is also an ingredient in most multivitamin

and essential fatty acids (500 mL of 10% emulsion provides 550 kcal). Guidelines include the following:

■ Parenteral nutritional solutions can be administered through central or peripheral IV lines. Some solutions are hypertonic (from high concentrations of glucose) and must be given in a central vein so they can be diluted rapidly. Solutions that contain 5% or 10% dextrose are less hypertonic and can be given in a peripheral vein. However, they are nutritionally incomplete and used for a limited time (about 5 to 7 days).

■ Fat emulsions are isotonic and may be given centrally or peripherally. When given peripherally, they are co-infused with dextrose–protein solution, to help protect the vein from phlebitis.

■ Dextrose–protein solutions are given through an in-line fi lter. Fat emulsions should not be fi ltered; they are “piggy-backed” into the IV line beyond the fi lter.

■ Solutions should be administered with an infusion pump to maintain a steady and accurate fl ow rate.

■ Sterile technique should be used in all aspects of prepara-tion, administration, and site care. Most agencies have spe-cifi c protocols for changing solution containers, administra-tion sets, and dressings at the venipuncture site.

Managing Vitamin DisordersEarly recognition and treatment of vitamin disorders can pre-vent a mild defi ciency or excess from becoming severe. For defi ciency states, oral vitamin preparations are preferred when possible. Multiple defi ciencies are common and a multivitamin preparation used to treat them usually contains more than the recommended daily amount. These products should be used for limited periods. When fat-soluble vitamins are given to correct a defi ciency, there is a risk of producing excess states. When water-soluble vitamins are given, excesses are less likely but may occur with large doses. For excess states, the usual treatment is to stop administration of the vitamin preparation. There are no specifi c antidotes or antagonists.

Vitamin A DisordersWith vitamin A defi ciency, assist patients to increase intake of foods containing preformed vitamin A (eg, meat, egg yolk, whole milk) or beta carotene (eg, yellow fruits and vegetables such as cantaloupe, peaches, carrots, sweet potatoes) when feasible. If a supplement is required, vitamin A alone may be preferred over a multivitamin unless multiple defi ciencies are present. Daily doses should not exceed 9,900 IU (approxi-mately 3,000 mcg RE; 1 mcg RE = 3.3 IU) unless a severe defi -ciency is present. Vitamin A may be given IM if GI absorption is severely impaired or ocular symptoms are severe. With vita-min A excess, immediately stop known sources of the vitamin.

Vitamin K DisordersWith vitamin K defi ciency, bleeding may occur spontaneously or in response to trauma. Thus, administration of vitamin K and measures to prevent bleeding are indicated. If the defi -ciency is not severe, oral vitamin K may be given for a few days



preparations for oral or parenteral use. People who smoke need to increase their intake of vitamin C by 35 mg per day to maintain an adequate vitamin C status.

In 2000, the DRI for vitamin C was increased to 75 mg for most adult women and 90 mg for most adult men. An addi-tional recommendation is to avoid large doses (ie, >1 g per day). With excessive intake of vitamin C supplements, the main concern is formation of calcium oxalate kidney stones and potential obstruction or other renal damage. There is no known benefi t of such large amounts, and their use should be discouraged.

Use of Vitamins in Preventing Cancer and Cardiovascular DiseaseVitamins with anti-oxidant effects (eg, C; E; beta carotene, a precursor of vitamin A) are thought to help prevent heart disease, cancer, and other illnesses. Anti-oxidants inactivate oxygen free radicals, potentially toxic substances formed dur-ing normal cell metabolism, and prevent or inhibit them from damaging body cells. In general, however, research studies are inconclusive and vitamin supplementation to prevent can-cer and cardiovascular disease is not currently recommended. Clinical trials continue in this area.

CancerVitamin A and beta carotene may reduce cancers of the lung, breast, oral mucosa, esophagus, and bladder. Vitamin A supple-ments are not recommended, but people are urged to increase dietary intake of fruits and vegetables that contain vitamin A and beta carotene. It is unknown whether anti-cancer effects stem from beta carotene or other components of fruits and vegetables.

Vitamin C, in diets with fi ve or more daily servings of fruits and vegetables, is associated with reduced risk of cancers of the GI tract (eg, oral cavity, esophagus, stomach, colon) and lung. However, in some studies, vitamin C supplements did not decrease the occurrence of stomach or colorectal cancer. Thus, the cancer-preventing effects of fruits and vegetables may be associated with factors other than vitamin C. Vitamin E has also been promoted for cancer prevention, but supplementa-tion to prevent cancer is not recommended (see accompanying Research Brief).

Cardiovascular DiseaseFolic acid and vitamin C are thought to have cardioprotec-tive effects. Folic acid is important in the metabolism of homocysteine, a toxic amino acid and a major risk factor for heart disease. Homocysteine is normally produced during metabolism of methionine, another amino acid. Several B vitamins, including folic acid, are required for the metabo-lism of homocysteine to a non-toxic substance, and an increased blood level of homocysteine occurs with folic acid defi ciency. Excessive homocysteine damages the endothelial lining of arteries and leads to plaque formation, atheroscle-rosis, and thrombosis. Folic acid supplements can prevent or delay these effects by lowering blood levels of homocysteine.

Effects of Vitamin E Supplementation

Source: Lonn, E., Bosch, J., Yusuf, S., et al. (2005). Effects of long-term vitamin E supplementation on cardiovascular events and cancer: A randomized controlled trial. Journal of the American Medical Association, 293(11), 1338–1347.Summary: This report is from the Heart Outcomes Preven-tion Evaluation (HOPE) clinical trial, conducted between December 1993 and April 1999; and its extension (HOPE-The Ongoing Outcomes or HOPE-TOO), continued from April 1999 until May 2003. HOPE involved >9,000 patients and HOPE-TOO involved >7,000 patients 55 years of age or older who had vascular disease or diabetes mellitus. The purpose of the study was to evaluate whether long-term vita-min E supplementation would decrease risks of cancer, cancer death, or major cardiovascular events (ie, myocardial infarc-tion, stroke, or cardiovascular death). The patients took a daily vitamin E supplement of 400 IU or placebo for a median duration of 7 y. Results indicated no differences between the vitamin E group and the placebo group in cancer incidence, cancer deaths, or major cardiovascular events. In addition, the vitamin E group had higher rates of heart failure and hospitalizations for heart failure than the placebo group. The researchers concluded that long-term vitamin E supplementa-tion does not prevent cancer or major cardiovascular events in patients with vascular disease or diabetes mellitus, and may increase the risk for heart failure, and should not be used in this population.Nursing implications: The main implication for the nurse may be to correct a common misconception that high-dose, long-term vitamin supplementation, including vitamin E, is benefi cial to health, and that even if it does not benefi t the recipient, it “can’t hurt.” For people 14 years of age and older, the RDA for vitamin E is 15 IU for males and females. Single vitamin E supplements may contain 100 to 1,000 IU per tablet or capsule; multivitamin preparations may contain various amounts but usually contain more than the RDA.

Although the Health Canada requirement that folic acid be added to cereal-grain foods may be helpful, the folic acid intake that helps prevent cardiovascular disease is thought to be higher.

Vitamin C is thought to help prevent cardiovascular dis-ease by anti-oxidant effects. The atherogenic effects of blood lipids, especially low-density lipoprotein (LDL) cholesterol (see Chap. 55), are attributed to their chemical breakdown or oxidation. Vitamin C may help prevent oxidation of LDL cholesterol. Overall, however, the effects of vitamin C on prevention of coronary artery disease (CAD) are unclear. Some studies indicate an increased risk for CAD only with a severe vitamin C defi ciency and that vitamin C has little effect on ischemic heart disease and stroke after adjustment for other risk factors. More research is needed before vita-min C supplements are recommended for cardioprotective



chloride per litre of fl uids at a fl ow rate of 100 to 125 mL per hour). An infusion pump should be used to control fl ow rate accurately. Also, serum potassium levels must be checked frequently and dosage adjusted if indicated.

Hyperkalemia■ Eliminate any exogenous sources of potassium, such as

potassium supplements, penicillin G potassium, salt substi-tutes, and blood transfusion with old blood.

■ Treat acidosis, if present, because potassium leaves cells and enters the serum with acidosis.

■ Use measures that antagonize the effects of potassium, that cause potassium to leave the serum and re-enter cells, and that remove potassium from the body. Appropriate measures are determined mainly by serum potassium levels and ECG changes. Continuous cardiac monitoring is required. If the following measures fail to reduce hyperkalemia, peritoneal dialysis or hemodialysis may be used.

With severe hyperkalemia (serum potassium above 7 mmol per L [mEq per L] and ECG changes indicating hyperkalemia), urgent treatment is required. IV sodium bicarbonate 45 mmol (mEq per L), over a 5-minute period, causes rapid movement of potassium into cells. This can be repeated in a few minutes if ECG changes persist. Calcium gluconate 10%, 5 to 10 mL IV, is also given early in the treat-ment to decrease the cardiotoxic effects of hyperkalemia. It is contraindicated if the patient is receiving digoxin, and it cannot be added to fl uids containing sodium bicarbonate because insoluble precipitates are formed. IV glucose and insulin may also be infused. This causes potassium to move into cells, though not as quickly as administration of sodium bicarbonate.

With less severe hyperkalemia (or when serum potassium levels have been reduced by other measures), sodium polysty-rene sulfonate, a cation exchange resin, can be given orally or rectally to remove potassium from the body. Each gram of the resin combines with 1 mmol (mEq) of potassium, and both are excreted in feces. The resin is usually mixed with water and sorbitol, a poorly absorbed, osmotically active alcohol that has a laxative effect. The sorbitol offsets the constipating effect of the resin and aids in its expulsion. Oral administration is pre-ferred, and several doses daily may be given until serum potas-sium is normal. When given as an enema, the solution must be retained from 1 to several hours, or repeated enemas must be given for therapeutic effect.

Magnesium DisordersHypomagnesemiaFor mild hypomagnesemia, oral magnesium preparations may be given. For moderate to severe and symptomatic hypomag-nesemia, parenteral (IV or IM) magnesium sulphate may be given daily as long as hypomagnesemia persists or continuing losses occur. Initial dosage may be larger, but the usual mainte-nance dose is approximately 8 mmol (mEq) daily. A 10% solu-tion is available in 10-mL vials that contain 8 mmol (mEq) of

effects, but increased intake of fruits and vegetables may be benefi cial.

Vitamin E has also been promoted for prevention of car-diovascular disease. Although some observational studies report benefi cial effects of vitamin E supplements, randomized clinical trials do not. A recent meta-analysis concluded that ≥400 IU per day of vitamin E increased all cause mortality and should be avoided.

Managing Mineral–Electrolyte DisordersWhen a mineral is given to correct a defi ciency state, there is a risk of producing an excess state. Because both defi ciencies and excesses may be harmful, the amount of mineral supple-ment should be titrated closely to the amount needed by the body. Larger doses are needed to treat defi ciency states than are needed to prevent defi ciencies from developing. When miner-al–electrolyte drug preparations are needed, oral products are preferred when possible. They are safer, less likely to produce toxicity, more convenient to administer, and less expensive than parenteral preparations.

Potassium DisordersHypokalemia■ Assess for conditions contributing to hypokalemia, and

attempt to eliminate them or reduce their impact.■ Assess severity by checking serum potassium levels and clin-

ical manifestations. Serum potassium levels alone are inad-equate because they may not accurately refl ect depletion of body potassium or shifts of potassium into cells.

■ In general, potassium supplements are indicated when serum potassium is below 3 mmol per L (mEq per L); when symptoms or electrocardiographic (ECG) changes indicate hypokalemia; and when patients are receiving digoxin, if necessary to maintain serum potassium above 3.5 mmol per L (mEq per L).

■ Potassium chloride is the drug of choice in most instances. Controlled-release tablets or capsules with potassium chlo-ride in a wax matrix or microencapsulated form are preferred over liquids by most patients; however, they may be more diffi cult to swallow.

■ IV potassium chloride is indicated when a patient cannot take an oral preparation or has severe hypokalemia. The serum potassium level should be measured and adequate urine output established before IV potassium therapy is started.

■ IV potassium chloride must be well diluted to prevent sud-den hyperkalemia, cardiotoxic effects, and phlebitis at the venipuncture site. The usual dilution is potassium chloride 20 to 40 mmol (mEq per L) per 1,000 mL of IV fl uid.

■ Dosage must be individualized. Patients receiving IV fl uids only are usually given 40 to 60 mmol (mEq per L) of potas-sium chloride daily (eg, 20 mmol [mEq per L] potassium



if no therapeutic response is evident within 3 to 4 weeks after drug therapy is begun.

■ Parenteral iron is indicated when oral preparations may fur-ther irritate a diseased GI tract, when the patient is unable or unwilling to take the oral drugs, or when the anemia must be corrected rapidly.

■ For severe iron defi ciency anemia, blood transfusions may be most effective.

Iron Excess■ Acute iron overdosage requires treatment as soon as pos-

sible, even if overdosage is only suspected and the amount taken is unknown. It is unnecessary to wait until the serum iron level is measured.

If treatment is begun shortly after oral ingestion of iron, aspiration of stomach contents by nasogastric tube or whole bowel irrigation with a polyethylene glycol solution (eg, Colyte) may be performed. Gastric lavage can be followed by instillation of 1% sodium bicarbonate solution to form insoluble iron carbonate compounds, or 5 to 8 g of deferox-amine (Desferal) dissolved in 50 mL of distilled water to bind the iron remaining in the GI tract and prevent its absorption. Deferoxamine may also be given IM or IV to bind with iron in tissues and allow its excretion in the urine. Throughout the treatment period, supportive measures may be needed for GI hemorrhage, acidosis, and shock.

■ For chronic iron overload or hemochromatosis, the fi rst step in treatment is to stop the source of iron, if possible. Phle-botomy is the treatment of choice for most patients because withdrawal of 500 mL of blood removes about 250 mg of iron. Phlebotomy may be needed as often as weekly and for as long as 2 to 3 years. For patients resistant to or intolerant of phlebotomy, deferoxamine can be given. Ten to 50 mg of iron is excreted daily in the urine with deferoxamine administration.

Effects of Vitamins and Minerals on Other DrugsFolic acid decreases effects of phenytoin, probably by accelerat-ing phenytoin metabolism, and may decrease absorption and effects of zinc. Niacin may increase the risk of rhabdomyoly-sis (a life-threatening breakdown of skeletal muscle) with sta-tin cholesterol-lowering drugs. Vitamin A in large doses, and possibly vitamin E, may increase the anti-coagulant effect of warfarin. Vitamin C, 1g daily or more, may decrease metabolism and increase the effects of estrogens and oral contraceptives. It is recommended that the daily dose of vitamin C not exceed 100 mg, to prevent this interaction.

Iron salts may decrease absorption of levodopa, levothy-roxine, methyldopa, penicillamine, fl uoroquinolones, and tetracyclines. Magnesium salts may decrease absorption and therapeutic effects of digoxin, fl uoroquinolones, nitrofuran-toin, penicillamine, and tetracyclines. Zinc salts may decrease absorption of fl uoroquinolones and most tetracyclines (doxycy-cline is apparently not affected).

magnesium sulphate for adding to IV solutions. A 50% solution is available in 2-mL vials (8 mmol [mEq]) for IM administration. Serum magnesium levels should be measured daily during treatment with a magnesium preparation.

Hypermagnesemia■ Stop any source of exogenous magnesium, such as mag-

nesium sulphate or magnesium-containing antacids and cathartics.

■ Have calcium gluconate available for IV administration. It is an antidote for the sedative effects of magnesium excess.

■ Increase urine output by increasing fl uid intake, if feasible. This increases removal of magnesium from the body in urine.

■ Patients with chronic renal failure (CRF) are the most likely to become hypermagnesemic. They may require peritoneal dialysis or hemodialysis to lower serum magnesium levels.

Iron Defi ciency and ExcessIron Defi ciency Anemia■ Anemia is a symptom, not a disease. Therefore, the underly-

ing cause must be identifi ed and eliminated, if possible.■ Encourage increased dietary intake of foods with high iron

content.■ Ferrous sulphate is usually the drug of choice for oral iron

therapy. Slow-release or enteric-coated products decrease absorption of iron, but may cause less gastric irritation.

■ Dosage is calculated in terms of elemental iron. Iron prepa-rations vary greatly in the amount of elemental iron they contain. Ferrous sulphate, for example, contains 20% iron; thus, each 300-mg tablet furnishes about 60 mg of elemen-tal iron. With the usual regimen of one tablet three times daily, a daily dose of 180 mg of elemental iron is given. For most patients, probably half that amount would correct the defi ciency. However, tablets are not manufactured in sizes to allow this regimen, and liquid preparations are not popular with patients. Thus, relatively large doses are usually given, but smaller doses may be effective, especially if GI symp-toms become a problem with higher dosages. Whatever the dose, only about 10% to 15% of the iron is absorbed. Most of the remainder is excreted in feces, which turn dark green or black.

■ Oral iron preparations are better absorbed if taken on an empty stomach. However, because gastric irritation is a common adverse reaction, they are more often given with or immediately after meals.

■ Although normal hemoglobin levels return after approxi-mately 2 months of oral iron therapy, an additional 6-month period of drug therapy is recommended to replenish the body’s iron stores.

■ Reasons for failure to respond to iron therapy include con-tinued blood loss, failure to take the drug as prescribed, or defective iron absorption. These factors must be re-evaluated



Parenteral nutrition may be indicated in infants and chil-dren who cannot eat or be fed enterally (eg, during medical illnesses or in perioperative conditions) to improve or main-tain nutritional status. Overall, benefi ts include weight gain, increased height, increased liver synthesis of plasma proteins, and improved healing and recovery.

With vitamins, children need suffi cient amounts to sup-port growth and normal body functioning. If supplements are given, considerations include the following:

■ Dosages should not exceed recommended amounts. There is a risk of overdosage by children and their parents. Because of manufacturers’ marketing strategies, many supplements are available in fl avours and shapes (eg, cartoon characters, animals) designed to appeal to children. Because younger children may think of these supplements as candy and take more than recommended, they should be stored out of reach and dispensed by an adult. Because parents’ desires to pro-mote health may lead them to give unneeded supplements or to give more than the recommended amounts, parents may need information about the potential hazards of vita-min overdoses.

■ Supplements given to children and adolescents should pro-vide the recommended amounts of vitamins. Except for single supplements of vitamin K and vitamin E in infants, multivitamin products are commonly used. For infants, liq-uid formulations usually include vitamins A, D, C, and B complex. Folic acid is not included because it is unstable in liquid form. For older children, chewable tablets usually con-tain vitamins A, D, C, and B complex, including folic acid.

■ A single IM dose of vitamin K is given to newborn infants to prevent hemorrhagic disease of newborns.

■ Preterm infants need proportionately more vitamins than term infants because their growth rate is faster and their absorption of vitamins from the intestine is less complete. A multivitamin product containing the equivalent of DRIs for term infants is recommended.

■ ULs have been established for some vitamins and these maximum daily amounts should not be exceeded. For other children, ULs vary according to age, as listed in Table 57-5.

Use in Special PopulationsNutritional Support in Ethnic PopulationsAlthough Canada’s Food Guide is inclusive in its diversity of choices related to the four food groups, it is often very diffi cult for some Aboriginal and Inuit populations to achieve these standards. Recent research has demonstrated that food choices based on traditional foods are more nutritionally adequate, than relying on modern foods. Health Canada has devised a Canada’s Food guide, Eating Well with Canada’s Food Guide: First Nations, Inuit and Metis, for these populations.

Acculturation is also changing food habits for Asian and Indian populations. Reliance on the low fat, high fruit and vegetable intake common in Chinese culture is being replaced by a typical Western diet favoured by younger, more highly educated Chinese who believe it is just as healthy. Diffi culty obtaining traditional foods is also a problem for some Indian populations who then must change their food preparation methods.

Nutritional Support in ChildrenChildren usually need suffi cient water, protein, carbohydrate, and fat in proportion to their size to support growth and increased physical activity. However, reports of childhood obe-sity and inadequate exercise are steadily increasing. Therefore, the goal of nutritional support is to meet needs without pro-moting obesity.

For children with special needs in relation to nutrients, var-ious enteral formulations are available for use. Some examples include Lofenalac for children with phenylketonuria (a disorder in which the amino acid phenylalanine cannot be metabolized normally); Nursoy and Prosobee, which contain soy protein, for children who are allergic to cow’s milk; and Nutramigen, Enfalac and Pregestimil, which contain easily digested nutrients for children with malabsorption or other GI problems.

With tube feedings, to prevent nausea and regurgitation, the recommended rate of administration is no more than 5 mL every 5 to 10 minutes for premature and small infants and 10 mL per minute for older infants and children. Preparation of formulas, positioning of children, and administration are the same as for adults to prevent aspiration and infection.

VITAMIN 1–3 Y 4–8 Y 9–13 Y 14–18 Y

D 50 mcg 50 mcg 50 mcg 50 mg

E 200 mg 300 mg 600 mg 800 mg

C 400 mg 650 mg 1,200 mg 1,800 mg

Folate 300 mcg 400 mcg 600 mcg 800 mcg

Niacin 10 mg 15 mg 20 mg 30 mg

Pyridoxine 30 mg 40 mg 60 mg 80 mg

Table 57-5 Vitamins: Tolerable ULs for Children



levels must be monitored. In addition, doses must be care-fully measured and given no more often than prescribed to avoid toxicity.

■ Accidental ingestion of iron-containing medications and dietary supplements is a common cause of poisoning death in children younger than 6 years of age. To help combat accidental poisoning, products containing iron must be labelled with a warning, and products with 30 mg or more of iron (eg, prenatal products) must be packaged as individual doses. All iron-containing preparations should be stored in places that are inaccessible to young children.

Nutritional Support in Older AdultsOlder adults are at risk of undernutrition with all nutrients. Inadequate intake may result from the inability to obtain and prepare food; disease processes that interfere with the ability to digest and use nutrients; and the use of drugs that decrease absorption of nutrients. A decrease in stomach acid in older adults may also reduce the ability to absorb nutrients. When alternative feeding methods (tube feedings, IV fl uids) are used, careful assessment of nutritional status is required to avoid defi -cits or excesses. With the high incidence of atherosclerosis, car-diovascular disease, and diabetes mellitus in older adults, it is especially important that intake of animal fats and high-calorie sweets be reduced.

Vitamin requirements are the same as for younger adults, but defi ciencies are common, especially of vitamins A and D, cyanocobalamin (B12), folic acid, ribofl avin, and thiamine. With vitamin B12, for example, it is estimated that those over 50 years only absorb 10% to 30% of the amount found in food. Every older adult should be assessed regarding vitamin intake (from foods and supplements) and use of drugs that interact with dietary nutrients. For most older adults, a daily multivi-tamin is probably desirable, even for those who seem healthy and able to eat a well-balanced diet. Health Canada recom-mends that all adults over the age of 50 should take a daily vitamin D supplement (400 IU). In addition, requirements may be increased during illnesses, especially those affecting GI func-tion. Overdoses, especially of the fat-soluble vitamins A and D, may cause toxicity and should be avoided. ULs for older adults have been established for some vitamins (D, 50 mcg or

With mineral–electrolytes, children need suffi cient amounts to support growth and normal body functioning. However, iron defi ciency is common in young children and teenage girls, and teaching about appropriate foods to eat is useful. An iron supplement may be needed. Guidelines include the following:

■ The Canadian Pediatric Society recommends term infants who are not breast-fed receive iron-fortifi ed formula from birth. Breast-fed infants do not need supplemental iron until after 6 months of age.

■ A combined vitamin–mineral supplement every other day may be reasonable, especially for children who eat poorly.

■ If supplements are given, dosages should be discussed with a health care provider and usually should not exceed the recommended amounts for particular age groups. ULs for children have been established for some minerals, and these maximum daily amounts should not be exceeded. They are listed in Table 57-6. The ULs for magnesium indicate maxi-mum intake from pharmaceutical preparations; they do not include intake from food and water.

■ All minerals and electrolytes are toxic in overdose and may cause life-threatening adverse effects. All such drugs should be kept out of reach of young children and should never be referred to as “candy.”

■ In areas where water is not fl uoridated, a vitamin–mineral supplement containing fl uoride may be indicated for infants and children. Fluoride may be prescribed by a physician, dentist, or nurse practitioner. In many provinces, public health departments provide a fl uoride rinse program for chil-dren who do not have fl uoride in their drinking water. Chil-dren must be guarded against excessive fl uoride ingestion and possible toxicity. Fluoride supplements are available for oral (tablets, chewable tablets, solutions) or topical (liquid rinse solutions or gels) uses. Supplements used by children or adults should be kept out of the reach of children; supple-ments prescribed for children should be used only with adult supervision; and children using topical preparations should be reminded to spit them out and not to swallow them.

■ If potassium chloride and other electrolyte preparations are used to treat defi ciency states in children, serum electrolyte

MINERAL BIRTH–6 MO 7–12 MO 1–3 Y 4–8 Y 9–13 Y 14–18 Y

Calcium No data No data 2.5 g 2.5 g 2.5 g 2.5 g

Phosphorus No data No data 3 g 3 g 4 g 4 g

Fluoride 0.7 mg 0.9 mg 1.3 mg 2.2 mg 10 mg 10 mg

Magnesium No data No data 65 mg 110 mg 350 mg 350 mg

Selenium 45 mcg 60 mcg 90 mcg 150 mcg 280 mcg 400 mcg

Table 57-6 Minerals: Tolerable ULs for Children



Many patients with CRF have hypertriglyceridemia, which is worsened by fat emulsions and may cause pancreatitis.

With vitamins, patients with ARF who are unable to eat an adequate diet need a vitamin supplement to meet DRIs. Large doses of vitamin C should be avoided because urinary excre-tion is impaired. In addition, oxalate (a product of vitamin C catabolism) may precipitate in renal tubules or form calcium oxalate stones, obstruct urine fl ow, and worsen renal function. Patients with CRF often have defi ciencies of water-soluble vitamins because many foods that contain these vitamins are restricted due to their potassium content. In addition, vitamin C is reabsorbed from renal tubules by a specifi c transport pro-tein. When the transport protein becomes saturated, remaining vitamin C is excreted in urine. Vitamin C is removed by dialysis and patients receiving dialysis require vitamin C replacement. The optimal replacement dose is unknown but probably should not exceed 200 mg per day (to avoid increased oxalate and pos-sible stones). Overall, a multivitamin with essential vitamins, including vitamin C 70 to 100 mg, pyridoxine 5 to 10 mg, and folic acid 1 mg, is recommended for daily use.

With mineral–electrolyte products, several are contraindi-cated in patients with renal impairment, including magnesium and potassium chloride, because of potential accumulation and toxicity. Frequent measurements of serum electrolyte levels may be indicated. In patients with CRF who are on hemodi-alysis and receiving supplemental erythropoietin therapy, two iron preparations have been developed to treat iron defi ciency anemia. Sodium ferric gluconate complex and iron sucrose may be given IV during dialysis.

Nutritional Support in Patients With Hepatic ImpairmentThe liver is extremely important in digestion and metabolism of carbohydrate, protein, and fat as well as storage of nutri-ents. Thus, patients with impaired hepatic function are often undernourished, with impaired metabolism of foodstuffs, vitamin defi ciencies, and fl uid and electrolyte imbalances. Depending on the disease process and the extent of liver impairment, these patients have special needs in relation to nutritional support.

■ Patients with alcoholic hepatitis or cirrhosis have a high rate of metabolism and therefore need foods to supply extra energy. However, metabolic disorders interfere with the liver’s ability to process and use foodstuffs. Patients with cir-rhosis often have hyperglycemia. Patients with severe hepa-titis often have hypoglycemia because of impaired hepatic production of glucose and possibly impaired hepatic metab-olism of insulin.

■ Protein restriction is usually needed in patients with cirrhosis to prevent or treat hepatic encephalopathy, which is caused by excessive protein or excessive production of ammonia (from protein breakdown in the GI tract). For patients able to tolerate enteral feedings (usually by GI tube), Hepatic Aid II is formulated for patients with liver failure. When parenteral nutrition is necessary for patients with hepatic

2,000 IU; E, 1,000 mg; C, 2,000 mg; folate, 1,000 mcg; niacin, 35 mg; pyridoxine, 100 mg) and these amounts should not be exceeded.

Applying Your Knowledge 57-1

You recognize that along with being undernourished,

Mrs. Farber is also most likely defi cient in vitamins.

You confer with the physician. What will be the likely

recommendation for Mrs. Farber?

Mineral–electrolyte requirements are also the same as for younger adults, but defi ciencies of calcium and iron are com-mon. Excess states also may occur in older adults. For example, decreased renal function promotes retention of magnesium and potassium. Hyperkalemia also may occur with the use of potas-sium supplements or salt substitutes. All minerals and electro-lytes are toxic in overdose. ULs for older adults (>65 years of age) have been established for calcium (2.5 g), phosphorus (3 to 4 g), fl uoride (10 mg), magnesium (350 mg), and selenium (400 mcg) and these maximum daily amounts should not be exceeded. In general, serum levels of minerals and electrolytes should be monitored carefully during illness, and measures taken to prevent either defi ciency or excess states.


It is important to assess patients for individual risk factors

related to gender, health status, and age. For Mrs. Farber,

what particular mineral–electrolyte defi ciencies would you

consider/explore?

Nutritional Support in Patients With Renal ImpairmentPatients with impaired renal function usually have multiple metabolic disorders such as hyperglycemia, accumulation of urea nitrogen (the end product of protein metabolism), and increased serum triglyceride levels from disordered fat metabo-lism. With enteral nutrition, Amin-Aid may be given to provide amino acids, carbohydrates, and a few electrolytes for patients with acute or chronic renal failure. With parenteral nutrition, several amino acid solutions are formulated for patients with renal failure. In addition, patients with acute renal failure (ARF) often have hyperkalemia, hyperphosphatemia, and hypermag-nesemia, so that potassium, phosphorus, and magnesium should be omitted until serum levels return to normal. IV fat emulsions should not be given to patients with ARF if serum triglycer-ide levels exceed 300 mg per dL. With CRF, high-calorie, low-electrolyte enteral formulations are usually indicated. Nepro is a formulation for patients receiving dialysis; Suplena, which is lower in protein and some electrolytes than Nepro, may be used in patients who are not receiving dialysis. Serum triglyceride levels should be measured before IV fat emulsions are given.



The usual dose is 2 to 4 mg, but some clinicians give 5 to 10 mg. Vitamin K is included in pediatric parenteral nutri-tion solutions.

■ Electrolyte and acid–base imbalances often occur in criti-cally ill patients and are usually treated as in other patients, with very close monitoring of serum electrolyte levels and avoiding excessive amounts of replacement products.

Nutritional Support in Home CareThe home care nurse is involved with nutritional matters in almost any home care setting. Because nutrition is so important to health, the home care nurse should take advantage of any opportunity for health promotion in this area. Health promo-tion may involve assessing the nutritional status of all members of the household, especially children, older adults, and those with obvious defi ciencies, and providing assistance to improve the nutritional status.

For patients receiving tube feedings at home, the home care nurse may teach as well as discuss the goals of treatment, administration, preparation or storage of solutions, equipment (eg, obtaining, cleaning), and monitoring responses (eg, weight, urine output).

For patients receiving parenteral nutrition at home, solu-tions, infusion pumps, and other equipment may be obtained from a pharmacy, home health agency, or independent com-pany. The home care nurse may not be involved in the initial setup but is likely to participate in ongoing patient care, monitoring of patient responses, and supporting caregivers. In addition, the home care nurse may need to coordinate activi-ties among physicians, IV therapy personnel, and other health care providers.

With vitamins, the home care nurse needs to assess for indications of vitamin defi ciencies and discuss the use of supplements, especially megadoses. If diffi culties are found, the nurse may need to counsel the household members about dietary sources of vitamins and adverse effects of excessive vitamin intake.

With mineral–electrolytes, the home care nurse needs to assess for indications of mineral–electrolyte defi ciency or excess. Depending on the assessment data, teaching and dis-cussion may be needed about dietary sources of these nutrients; when mineral supplements are indicated or should be avoided; and safety factors related to iron supplements or exposure to lead in homes with small children.


How Can You Avoid This Medication Error?Mrs. Farber is taking an iron supplement. You tell the family

to give her the iron supplement with her morning coffee.

failure and hepatic encephalopathy, HepatAmine, a special formulation of amino acids, may be used. Other amino acid preparations are contraindicated in patients with hepatic encephalopathy and coma. Lactulose is also given to treat hepatic encephalopathy.

■ Enteral and parenteral fat preparations must be used very cautiously. Medium-chain triglycerides (eg, MCT oil), which are used to provide calories in other malnourished patients, may lead to coma in patients with advanced cirrho-sis. Patients who require parenteral nutrition may develop high serum triglyceride levels and pancreatitis if given usual amounts of IV fat emulsions.

■ Sodium and fl uid restrictions are often needed to decrease edema.

■ Vitamin defi ciencies commonly occur in patients with chronic liver disease because of poor intake and malabsorp-tion. With hepatic failure, hepatic stores of vitamin A, pyri-doxine, folic acid, ribofl avin, pantothenic acid, vitamin B12, and thiamine are depleted. Folic acid defi ciency may lead to megaloblastic anemia. Thiamine defi ciency may lead to Wernicke’s encephalopathy. Therapeutic doses of vitamins should be given for documented defi ciency states.

Niacin is contraindicated in liver disease because it may increase liver enzymes (alanine and aspartate amin-otransferase, alkaline phosphatase) and bilirubin and cause further liver damage. Long-acting dosage forms may be more hepatotoxic than the fast-acting forms.

■ Iron dextran must be used with extreme caution in patients with impaired hepatic function. Also, overdoses of chro-mium and copper are hepatotoxic and should be avoided.

Nutritional Support in Patients With Critical IllnessCritically ill patients often have organ failures that alter their ability to ingest and use essential nutrients. Thus, they may be undernourished in relation to protein-calorie, vitamin, and mineral–electrolyte needs. Some considerations include the following:

■ With enteral nutrition, adequate calories and DRI- equivalent amounts of all vitamins are usually needed. Patients with respiratory impairment may need a formula that contains less carbohydrate and more fat than other products and produces less carbon dioxide (eg, Pulmocare, Nutrivent). Patients with cardiac or renal impairment who require fl uid restriction may benefi t from a more concen-trated formula (eg, 1.5 kcal per mL).

■ With parenteral nutrition, adequate types and amounts of nutrients are needed. When IV fat emulsions are given, they should be infused slowly, over 24 hours. Those for adults do not contain vitamin K, which is usually injected weekly.



NURSING ACTIONS RATIONALE/EXPLANATION

1. Administer accuratelya. For oral supplemental feedings, chill liquids or pour

over ice and give through a straw, from a closed con-tainer, between meals.

Chilling (or freezing) may improve formula taste and decrease formula odour. A straw directs the formula toward the back of the throat and decreases its contact with the taste buds. A closed container also decreases odour. Giving between meals may have less effect on appetite at mealtimes.

b. For tube feedings(1) Have the patient sitting, if possible. To decrease risks of aspirating formula into lungs.(2) Check tube placement before each feeding. To prevent aspiration or accidental instillation of feedings into

lungs.(3) Give the solution at room temperature. Cold formulas may cause abdominal cramping.(4) If giving by intermittent instillation, do not give

>500 mL per feeding, including water for rinsing the tube.

To avoid gastric distention, possible vomiting, and aspiration into lungs.

(5) Give by gravity fl ow (over 30–60 min) or infusion pump.

Rapid administration may cause nausea, vomiting, and other symptoms.

(6) With continuous feedings, change the containers and tubing daily. With intermittent bolus feedings, rinse all equipment after each use and change at least q24h.

Most tube-feeding formulas are milk based and provide a good culture medium for bacteria growth. Clean technique, not sterile technique, is required.

(7) Give additional water with, after, or between feedings.

To avoid dehydration and promote fl uid balance. Most patients receiving 1,500–2,000 mL of tube-feeding formula daily will need 1,000 mL or more of water daily.

(8) Rinse the nasogastric tubes with at least 50–100 mL water after each bolus feeding or administration of medications through the tube.

To keep the tube patent and functioning. This water is included in the calculation of fl uid intake.

(9) When medications are ordered by tube, liquid prepa-rations, when available, are preferred over crushed tablets or powders emptied from capsules.

Tablets or powders may stick in the tube lumen. This may mean the full dose of the medication does not reach the stomach. Also, the tube is likely to become obstructed.

c. With pancreatic enzymes, give before or with meals or food.

To be effective, these agents must be in the small intestine when food is present.

d. With fat-soluble vitamins(1) Do not give oral preparations at the same time as

mineral oil.Mineral oil absorbs the vitamins and thus prevents their sys-temic absorption.

(2) For subcutaneous or IM administration of vitamin K, aspirate carefully to avoid IV injection, apply gentle pressure to the injection site, and inspect the site frequently. For IV injection, vitamin K may be given by direct injection or diluted in IV fl uids (eg, 5% dextrose in water or saline).

Vitamin K is given to patients with hypoprothrombinemia, which causes bleeding tendencies. Thus, any injection may cause trauma and bleeding at the injection site so is rarely used.

(3) Administer IV vitamin K slowly, at a rate not exceed-ing 1 mg/min, whether diluted or undiluted.

IV phytonadione may cause hypotension and shock from an anaphylactic type of reaction.

e. With B-complex vitamins(1) Give parenteral cyanocobalamin (vitamin B12) IM or

deep subcutaneous.(2) Give oral niacin, except for timed-release forms, with

or after meals or at bedtime. Have the patient sit or lie down for about 30 min after administration.

To decrease anorexia, nausea, vomiting, diarrhea, and fl atu-lence. Niacin causes vasodilation, which may result in dizziness, hypotension, and injury from falls. Vasodilation occurs within a few minutes and may last 1 h.

(3) Give IM thiamine deeply into a large muscle mass. Avoid the IV route.

To decrease pain at the injection site. Hypotension and anaphy-lactic shock have occurred with rapid IV administration and large doses.

f. With mineral–electrolyte preparations, give oral drugs with food or immediately after meals; give IV prepa-rations slowly, do not mix with any other drug in a syringe, and dilute as directed with compatible IV solutions.

Giving oral drugs with or after food decreases gastric irritation. Rapid IV administration may cause cardiac dysrhythmias or other serious problems. Mixing the drugs may cause drug inacti-vation or precipitation.

Nutritional Products, Vitamins, and Mineral–Electrolytes





g. For potassium supplements(1) For oral preparations, give with or after meals; do not

crush controlled- or extended-release tablets; mix oral liquids, powders, and effervescent tablets in at least 120 mL of juice, water, or carbonated beverage.

Giving with food decreases gastric irritation; crushing extended-release tablets causes the drug to be absorbed imme-diately rather than over several hours, as intended; mixing dilutes, disguises the taste, and decreases gastric irritation.

(2) For IV potassium chloride, never give undiluted drug IV; dilute 20–60 mmol (mEq) in 1,000 mL of IV solution, such as dextrose in water; be sure that potassium chlo-ride is mixed well with the IV solution; as a general rule, give potassium-containing IV solutions at a rate that administers approximately 10 mEq/h or less; for life-threatening dysrhythmias caused by hypokalemia, potassium can be replaced with 20–40 mmol (mEq)/h with constant electrocardiogram (ECG) monitoring. Use an infusion pump and do not give potassium- containing IV solutions into a central venous catheter.

Concentrated drug and transient hyperkalemia may cause life-threatening cardiotoxicity, severe pain, and vein sclerosis; adequate dilution decreases risks of hyperkalemia and cardiotox-icity and prevents or decreases pain at the infusion site; 10 mmol (mEq) or less per hour is the safest amount and rate of potassium administration and it is usually effective; risks of hyperkalemia and life-threatening cardiotoxicity are greatly increased with high concentrations or rapid fl ow rates. Constant ECG monitor-ing can detect hyperkalemia. Infusion pumps can regulate the fl ow rate accurately. Administration through a central IV line can cause hyperkalemia and cardiac dysrhythmias or arrest.

A variety of premixed IV solutions containing differ-ent amounts of potassium chloride are commercially available.

Check carefully to ensure the correct strength of potassium in solution is chosen; errors are potentially fatal.

h. For parenteral magnesium sulphate (MgSO4)(1) Read the drug label carefully to be sure you have the

correct preparation for the intended use.MgSO4 is available in concentrations of 10%, 25%, and 50% and in sizes of 2-, 10-, and 20-mL ampoules, as well as a 30-mL multi-dose vial.

(2) For IM use, small amounts of 50% solution are usu-ally given (1 g MgSO4 = 2 mL of 50% solution).

(3) For IV use, a 5% or 10% solution is used for direct injection, intermittent infusion, or continuous infu-sion. Whatever concentration is used, administer no >150 mg/min (1.5 mL/min of 10% solution; 3 mL/min of 5% solution).

i. For iron preparations(1) Give tablets or capsules before meals, with 240 mL

of water or juice, if tolerated. If gastric upset occurs, give with or after meals. Instruct patients not to crush or chew sustained-release preparations.

Iron preparations are absorbed better if taken on an empty stomach. If taken with meals, note that bran, eggs, tea, coffee, and dairy products decrease iron absorption. Crushing or chew-ing releases all the medication at once, rather than over several hours, as intended.

(2) Dilute liquid iron preparations, give with a straw, and have the patient rinse the mouth afterward.

To prevent temporary staining of teeth.

(3) To give iron dextran IM, use a 2- to 3-in. needle and Z-track technique to inject the drug into the upper outer quadrant of the buttock.

To prevent discomfort and staining of subcutaneous tissue and skin.

(4) To give iron dextran IV (either directly or diluted in sodium chloride solution and given over several hours), do not use the multi-dose vial.

The multi-dose vial contains phenol as a preservative and is not suitable for IV use. Ampoules of 2 or 5 mL are available without preservative.

j. Refer to the individual drugs or package literature for instructions regarding administration of deferoxamine, penicillamine, IV sodium bicarbonate, and multiple electrolyte solutions.

2. Assess for therapeutic effectsa. With nutritional formulas given orally or by tube feed-

ing, assess for weight gain and increased serum albu-min. For infants and children receiving milk substitutes, assess for decreased diarrhea and weight gain.

Therapeutic effects depend on the reason for use (ie, prevention or treatment of undernutrition).

b. With pancreatic enzymes, assess for decreased diarrhea and steatorrhea.

The pancreatic enzymes function the same way as endogenous enzymes to and digestion of carbohydrate, protein, and fat.

c. With vitamins, assess for decreased signs and symp-toms of defi ciency:(1) With vitamin A, assess for improved vision, especially in

dim light or at night, less dryness in eyes and conjunc-tiva (xerophthalmia), and improvement in skin lesions.

Night blindness is usually relieved within a few days. Skin lesions may not disappear for several weeks.

Nutritional Products, Vitamins, and Mineral–Electrolytes (continued)




(2) With vitamin K, assess for decreased bleeding and more nearly normal blood coagulation tests (eg, prothrombin time).

Blood coagulation tests usually improve within 4–12 h.

(3) With B-complex vitamins, assess for decreased or absent stomatitis, glossitis, seborrheic dermatitis, neurologic problems (neuritis, convulsions, mental deterioration, psychotic symptoms), cardiovascular problems (edema, heart failure), and eye problems (itching, burning, photophobia).

Defi ciencies of B-complex vitamins commonly occur together and produce many similar manifestations.

(4) With vitamin B12 and folic acid, assess for increased appetite, strength and feeling of well-being, increased reticulocyte counts, and increased num-bers of normal RBCs, hemoglobin, and hematocrit.

Therapeutic effects may be rapid and dramatic. The patient usually feels better within 24–48 h, and normal RBCs begin to appear. Anemia is decreased within approximately 2 weeks, but 4–8 weeks may be needed for complete blood count to return to normal.

(5) With vitamin C, assess for decreased or absent mal-aise, irritability, and bleeding tendencies (easy bruis-ing of skin, bleeding gums, nosebleeds, and so forth).

d. With mineral–electrolyte preparations, assess for decreased signs of defi ciency.(1) With potassium chloride or other potassium prepa-

rations, assess for decreased signs of hypokalemia and increased serum potassium levels.

(2) With MgSO4, assess for decreased signs of hypomag-nesemia, increased serum magnesium levels, or control of convulsions.

(3) With zinc sulphate (ZnSO4), assess for improved wound healing.

(4) With iron preparations, assess for increased vigour and feeling of well-being, improved appetite, less fatigue, and increased RBCs, hemoglobin, and hema-tocrit. With parenteral iron, assess for an average increase in hemoglobin of 1 g/week.

Therapeutic effects are usually evident within a month unless other problems are also present (eg, vitamin defi ciency, achlo-rhydria, infection, malabsorption).

3. Assess for adverse effectsa. With commercial nutritional formulas (except Osmo-

lite and Isocal), assess for hypotension, tachycardia, increased urine output, dehydration, nausea, vomiting, or diarrhea.

These adverse reactions are usually attributed to the hyperto-nicity of the preparations. They can be prevented or minimized by starting with small amounts of formula, given slowly.

b. With vitamin A, assess for signs of hypervitaminosis A (anorexia; vomiting; irritability; headache; skin disor-ders; pain in muscles, bones, and joints; other clinical manifestations; and serum levels of vitamin A above 75–2,000 retinol activity equivalent [RAE]/100 mL).

Severity of manifestations depends largely on dose and duration of excess vitamin A intake. Very severe states produce addi-tional clinical signs, including enlargement of liver and spleen, altered liver function, increased intracranial pressure, and other neurologic manifestations.

c. With vitamin K, assess for hypotension and signs of anaphylactic shock with IV phytonadione.

Vitamin K rarely produces adverse reactions. Giving IV phy-tonadione slowly may prevent adverse reactions.

d. With B-complex vitamins, assess for hypotension and anaphylactic shock with parenteral niacin, thiamine, cyanocobalamin, and folic acid; anorexia, nausea, vom-iting and diarrhea, and postural hypotension with oral niacin.

Adverse reactions are generally rare. They are unlikely with B-complex multivitamin preparations. They are most likely to occur with large IV doses and rapid administration.

e. With vitamin C megadoses, assess for diarrhea and rebound defi ciency if stopped abruptly.

Adverse reactions are rare with usual doses and methods of administration.

f. With mineral–electrolytes, assess for excess states. These are likely to occur with excessive dosages of supple-ments. They can usually be prevented by using relatively low doses in non-emergency situations and by frequent monitoring of serum levels of electrolytes and iron.

g. With potassium preparations, assess for hyperkalemia. This is most likely to occur with rapid IV administration, high dosages or concentrations, or in the presence of renal insuffi -cency and decreased urine output.

h. With magnesium preparations, assess for hypermagnesemia.

See potassium preparations, above.

i. GI symptoms—anorexia, nausea, vomiting, diarrhea, and abdominal discomfort from gastric irritation.

Most oral preparations of minerals and electrolytes are likely to cause gastric irritation. Taking the drugs with food or 240 mL of fl uid may decrease symptoms.





j. Cardiovascular symptoms—cardiac dysrhythmias, hypotension, tachycardia, and other symptoms of shock.

Potentially fatal dysrhythmias may occur with hyperkalemia or hypermagnesemia; shock may occur with deferoxamine and iron dextran injections.

k. With sodium polystyrene sulfonate, assess for hypokalemia, hypocalcemia, hypomagnesemia, and edema.

Although this drug is used to treat hyperkalemia, it removes cal-cium and magnesium ions as well as potassium ions. Because it acts by trading sodium for potassium, the sodium retention may lead to edema.

4. Assess for drug interactionsa. With fat-soluble vitamins

(1) Bile salts increase effects. Increase intestinal absorption(2) Laxatives, especially mineral oil, and orlistat decrease

effects.Mineral oil and orlistat combine with fat-soluble vitamins and prevent their absorption if both are taken at the same time. Excessive or chronic laxative use decreases intestinal absorption.

(3) Antibiotics may decrease effects. With vitamin K, antibiotics decrease production by decreasing intestinal bacteria. With others, antibiotics may cause diarrhea and subsequent malabsorption.

b. With B-complex vitamins By increasing urinary excretion of vitamin B-complex.(1) Isoniazid (INH) decreases effect. INH has an anti-pyridoxine effect. When INH is given for pre-

vention or treatment of tuberculosis, pyridoxine is also usually given.

(2) With folic acid––alcohol, cholestyramine, methotrex-ate, oral contraceptives, phenytoin, sulfasalazine, and triamterene decrease effects.

Alcohol alters liver function and leads to poor hepatic storage of folic acid. Methotrexate and phenytoin act as antagonists to folic acid and may cause folic acid defi ciency. Cholestyramine, oral contraceptives, and sulfasalazine decrease absorption of folic acid.

(3) With vitamin B12, omeprazole (Losec) decreases effects.

Decreases absorption of B12 from foods.

c. Drugs that increase effects of minerals and electrolytes and related drugs:(1) Cation exchange resin (Kayexalate): diuretics

increase potassium loss; other sources of sodium increase the likelihood of edema.

Additive effects

(2) With iron salts(a) Allopurinol (Zyloprim) This drug may increase the concentration of iron in the liver. It

should not be given concurrently with any iron preparation.(b) Ascorbic acid (vitamin C) Increases absorption of iron by acidifying secretions

(3) With potassium salts(a) Angiotensin-converting enzyme (ACE) inhibitors

(eg, captopril)May increase risks of hyperkalemia

(b) Diuretics, potassium-sparing (spironolactone, triamterene, amiloride)

These drugs should not be given with a potassium supplement because of additive risks of producing life-threatening hyper-kalemia.

(c) Salt substitutes These contain potassium rather than sodium and may cause hyperkalemia if given with potassium supplements.

(d) Penicillin G potassium This potassium salt of penicillin contains 1.7 mmol (mEq) of potas-sium per 1 million units and increases risks of hyperkalemia.

d. Drugs that decrease effects of minerals and electrolytes and related drugs:(1) With oral iron salts

(a) Antacids Decrease absorption. Iron is best absorbed in an acidic environ-ment and antacids increase alkalinity.

(b) Caffeine Decreases absorption. An iron preparation and a caffeine- containing substance (eg, coffee) should be separated by at least 2 h.

(c) Pancreatic extracts Decrease absorption(2) With potassium salts

(a) Calcium gluconate Decreases cardiotoxic effects of hyperkalemia and is therefore useful in the treatment of hyperkalemia

(b) Sodium polystyrene sulfonate (Kayexalate) Used in the treatment of hyperkalemia because it removes potassium from the body

Nutritional Products, Vitamins, and Mineral–Electrolytes (continued)



■ Human nutrition for health requires suffi cient water, carbo-hydrates, proteins, fats, vitamins, and minerals.

■ Patients with other health problems often have nutritional defi ciencies, such as protein-caloried undernutrition and vitamin defi ciencies.

■ All patients need to be assessed in terms of nutritional sta-tus. When problems are assessed, interventions to maintain or improve nutritional status are needed.

■ Fat-soluble vitamins are A, D, E, and K; water-soluble vitamins are B complex and C.

■ Nutrients are best obtained from foods; when they can-not be obtained from foods, they can be provided by oral,

enteral (via GI tubes), or parenteral (IV) feedings to meet a patient’s nutritional needs.

■ Techniques for safe administration of oral, enteral, and parenteral feedings must be consistently followed because complications and harm to patients may occur with all methods.

■ Adverse effects may occur with large doses of vitamin and mineral supplements; the maximum recommended amounts should not be exceeded.

■ Although most adults and children probably benefi t from a daily multivitamin, large doses of single vitamins do not pre-vent cancer or cardiovascular disease and should be avoided.

Key Concepts

Short Answer Exercises

1. For patients who are unable to ingest food, which nutrients can be provided with enteral or IV nutritional formulas?

2. What is the role of lipid emulsions in parenteral nutrition?

3. What roles do vitamins play in normal body functioning?

4. Identify patient populations who are at risk for vitamin defi ciencies and excesses.

5. Are fat-soluble or water-soluble vitamins more toxic in overdoses? Why?

6. For a patient who asks your advice about taking a multivi-tamin supplement daily, how would you reply? Justify your answer.

7. How do the vitamin requirements of children, older adults, and critically ill patients differ from those of healthy young and middle-aged adults?

8. What are the major roles of minerals and electrolytes in normal body functioning?

9. When a patient is given potassium supplements for hypokalemia, how do you monitor for therapeutic and adverse drug effects?

10. List the main steps in the treatment of hyperkalemia. Identify patient populations at risk for development of hyperkalemia.

11. What are the advantages and disadvantages of iron sup-plements?

12. List the measures an adult can take to prevent accidental iron poisoning in small children.

CRNE-Style Questions

13. Mr. H. develops respiratory distress while receiving con-tinuous tube feeding. After stopping the feeding which of the following actions should the nurse take?a. Assess bowel sounds to determine if he has a paralytic

ileus.b. Assess breath sounds to determine if he has aspirated

tube-feeding formula.c. Perform nasal or tracheal suctioning.d. Aspirate stomach contents.

Review and Application Exercises

57-1 Include the administration of a multivitamin with

her daily nourishment. The undernourished fre-

quently have defi ciencies in vitamins A, D, B12, folic

acid, ribofl avin, and thiamine.

57-2 In the elderly, the most common mineral–electro-

lyte defi ciencies are of calcium and iron. Excess

states are also possible. Serum levels of minerals

and electrolytes should be monitored carefully and

measures taken to prevent both defi ciency and

excess.

57-3 Iron preparations are to be administered before

meals for best absorption. When given with coffee,

tea, or dairy products, absorption is decreased.

Applying Your Knowledge Answers



14. Which of the following statements by Mr. H.’s daughter, who will care for him at home, leads you to believe that she has understood your teaching regarding tube feedings?a. “I will store unopened cans of formula in the

refrigerator.”b. “I will stop the feedings if he has >2 stools/d.”c. “I will place him in a sitting position for his feedings.”d. “I will give no >50 mL/h.”

15. Which of the following is a fat-soluble vitamin that is toxic in overdose?a. Vitamin Ab. Vitamin B1

c. Vitamin Cd. Folic acid

16. Which of the following statements should be included in teaching a patient who is being started on an iron supplement?a. The preparation may cause diarrhea.b. The preparation may cause stools to be dark green or

black.c. The preparation should be taken with an antacid.d. The preparation should not be taken with fruit juice.

17. Which of the following IV electrolytes must be well diluted and never given as a bolus injection because it can cause fatal cardiac dysrhythmias?a. Sodium bicarbonateb. Magnesium sulphatec. Sodium chlorided. Potassium chloride

Selected References

Brophy, D. F., & Gehr, T. W. B. (2005). Disorders of potassium and magnesium homeostasis. In J. T. DiPiro, R. L. Talbert, G. C. Yee, et al. (Eds.), Pharmacotherapy: A pathophysiologic approach (6th ed., pp. 967–982). New York: McGraw-Hill.

Canadian Pharmacists Association. (2009). Compendium of pharma-ceuticals and specialties. Ottawa, ON: Author.

Christofi es, A., Schauer, C., & Zlotkin, S.H. (2005). Iron defi -ciency and anemia prevalence and associated etiologic risk factors in First Nations and Inuit communities in Northern Ontario and Nunavut. Canadian Journal of Public Health, 96(4), 304–307.

DeHart, R. M., & Worthington, M. A. (2005). Nutritional consid-erations in major organ failure. In J. T. DiPiro, R. L. Talbert, G. C. Yee, et al. (Eds.), Pharmacotherapy: A pathophysiologic approach (6th ed., pp. 2635–2658). New York: McGraw-Hill.

Facts & Comparisons. (Updated monthly). Drug facts and compari-sons. St. Louis, MO: Author.

Giles, H., & Vijayan, A. (2004). Fluid and electrolyte manage-ment. In G. B. Green, I. S. Harris, G. A. Lin, et al. (Eds.), The Washington manual of medical therapeutics (31st ed., pp. 39–71). Philadelphia, PA: Lippincott Williams & Wilkins.

Health Canada. (2007). Eating well with Canada’s food guide. Retrieved May 21, 2009, from http://www.hc-sc.gc.ca/fn-an/food guide-ailment/index-eng.php

Health Canada. (2007). Eating Well with Canada’s Food Guide: First Nations, Inuit and Metis. Retrieved. May 21, 2009, from http://www.hc-sc.gc.ca/hl-vs/alt_formats/pacrb-dgapar/pdf/iyh-vsv/life-vie/obes-eng.pdf

Health Canada. Dietary reference intakes (2006). Retrieved June 27, 2009, from http://www.hc-sc.gc.ca/fn-an/nutrition/reference/reports-rapports/index-eng.php

Heyland, D. K., Dhaliwal, R., Drover, J. W., et al., and the Canadian Critical Care Clinical Practice Guidelines Committee. (2003). Canadian clinical practice guidelines for nutrition support in mechanically venti-lated, critically ill adult patients. Journal of Parenteral and Enteral Nutrition, 27(5), 355–373.

Johnson-Down, L., Ritter, H., Starkey, L. J., et al. (2006). Primary food sources of nutrients in the diet of Canadian adults. Canadian Journal of Dietary Practices and Research, 67(1), 7–13.

Mahan, L. K., & Escott-Stump, S. (Eds.). (2004). Krause’s food, nutrition, and diet therapy (11th ed.). Philadelphia, PA: W. B. Saunders.

Mason, J. B. (2004). Consequences of altered micronutrient status. In L. Goldman, & D. Ausiello (Eds.), Cecil textbook of medicine (22nd ed., pp. 1326–1336). Philadelphia, PA: W. B. Saunders.

McMahon, M. M. (2004). Parenteral nutrition. In L. Goldman, & D. Ausiello (Eds.), Cecil textbook of medicine (22nd ed., pp. 1322–1326). Philadelphia, PA: W. B. Saunders.

Miller, E., Pastor-Barriuso, P., Dalal, D., et al. (2005). Meta-analysis: High-dosage vitamin E supplementation may increase all-cause mortality. Annals of Internal Medicine, 142(1). Retrieved June 26, 2009, from http://www.annals.org/cgi/reprint/0000605–200501040–00110v1.pdf

Pronsky, Z. M., & Crowe, J. P. (2005). In L. K. Mahan & S. Escott-Stump (Eds.), Krause’s food, nutrition, and diet therapy (11th ed., pp. 455–474). Philadelphia, PA: W. B. Saunders.

Reiter, P. D., & Sacks, G. S. (2005). Prevalence and signifi cance of malnutrition. In J. T. DiPiro, R. L. Talbert, G. C. Yee, et al. (Eds.), Pharmacotherapy: A pathophysiologic approach (6th ed., pp. 2579–2590). New York: McGraw-Hill.

Rock, C. L. (2004). Nutrition in the prevention and treatment of disease. In L. Goldman & D. Ausiello (Eds.), Cecil textbook of medicine (22nd ed., pp. 1308–1311). Philadelphia, PA: W. B. Saunders.

Rombeau, J. L. (2004). Enteral nutrition. In L. Goldman, & D. Ausiello (Eds.), Cecil textbook of medicine (22nd ed., pp. 1319–1322). Philadelphia, PA: W. B. Saunders.

Smeltzer, S. C., & Bare, B. G. (2008). Brunner & Suddarth’s text-book of medical-surgical nursing (10th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.

Torrance, G. M., Hooper, M. D., & Reeder, B. A. (2002). Trends in overweight and obesity among adults in Canada (1970–1992): Evidence from national surveys using measured height and weight. International Journal of Obesity and Related Metabolism Disorders, 26(6), 797–804.


http://www.hc-sc.gc.ca/fn-an/foodguide-ailment/index-eng.php


http://www.hc-sc.gc.ca/hl-vs/alt_formats/pacrb-dgapar/pdf/iyh-vsv/life-vie/obes-eng.pdf


http://www.hc-sc.gc.ca/fn-an/nutrition/reference/reports-rapports/index-eng.php

http://www.hc-sc.gc.ca/fn-an/nutrition/reference/reports-rapports/index-eng.php

http://www.annals.org/cgi/reprint/0000605%E2%80%93200501040%E2%80%9300110v1.pdf

937937

Applying Your KnowledgePauline McKay, aged 51, has had a weight problem all her life. She has been on countless diets,

but always with the same result: she loses weight, and then regains it plus additional weight.

She is 191 cm tall and weighs 120.5 kg. Her physician starts her on orlistat (Xenical).

Introduction

Carbohydrates, proteins, and fats are required for human nutrition. Either defi ciencies or excesses impair health, cause illness, and impair recovery from illness or injury. Proteins are basic anatomic and physiologic components of all body cells and tissues; carbohydrates and fats serve primarily as sources of energy for cellular metabolism. Energy is measured in kilocalories (kcal, commonly called calories) per gram of food oxidized in the body. Carbohydrates and proteins supply 4 kcal per g; fats supply 9 kcal per g. Excessive amounts of any of these nutrients are converted to fat and stored in the body, resulting in overweight and obesity. This chapter discusses obesity and pharmacological and non-pharmacological treatment strategies, to aid weight loss and weight maintenance.

Overweight and Obese AdultsOverweight and obesity are worldwide problems and are increasing in Canada, in both children and adults. Statistics Canada reports that two out of every three adults in Canada are overweight or obese. The proportion of obese children has tripled in the last 25 years. Obesity is a risk factor in a number of chronic diseases; a healthy weight is important in reducing the risk of those diseases and to improve overall health. In the First Report of the Institute of Wellbeing, 67% of Canadian teenagers report excellent or very good health down from 80% in 1998. Health Canada classifi es overweight as a body mass index (BMI) of 25 to 29.9 kg per m2; obese is classifi ed as a BMI of 30 or more kg per m2. The BMI refl ects weight in relation to height and is a better indicator than weight alone. The desirable range for BMI is 18.5 to 24.9 kg per m2 of body surface, with values below

OBJECTIVESAfter studying this chapter, you will be able to:

1. Promote healthful lifestyle measures to maintain body weight within a desirable range and avoid obesity.

2. Assess patients for risk factors and manifestations of obesity.3. Calculate body mass index (BMI).4. Counsel patients about the health consequences of obesity.5. Assist overweight patients to develop and maintain a safe and realistic

weight-loss program.6. Identify reliable sources for information about nutrition, weight loss, and

weight maintenance.7. Discuss nursing process implications of approved weight-loss drugs.

KEY TERMS■ Anorexiants■ Body mass index■ Obesity■ Overweight

Drugs to Aid Weight Management

C H A P T E R

58

937



Physiologic FactorsIn general, increased weight is related to an energy imbalance in which energy intake (food/calorie consumption) exceeds energy expenditure. Total energy expenditure represents the energy expended at rest (ie, the basal or resting metabolic rate), during physical activity, and during food consumption. When a person ingests food, about 10% of the energy con-tent of that food is expended in the digestion, absorption, and metabolism of nutrients. Foods that contain carbohydrates and proteins stimulate energy expenditure; high-fat foods have little stimulatory effect. The energy required to metabolize and to use food reaches a maximum level about 1 hour after the food is ingested. In addition, men tend to expend more energy than women because men have proportionally more muscle mass. Energy expenditure usually decreases in older men and women of all ages because these groups have less muscle tissue and more adipose tissue. Muscle is more metabolically active (ie, has higher energy needs and burns more calories) than adi-pose tissue.

Excessive weight can result from eating more calories, exercising less, or a combination of the two factors. Con-suming an extra 500 calories each day for a week results in 3,500 excess calories or 1 lb of fat. Excess calories are converted to triglycerides and stored in fat cells (adipocytes). With con-tinued intake of excessive calories, fat cells increase in both size and number.

Genetic FactorsVarious studies indicate that a signifi cant portion of weight variation within a given environment is genetic in origin. For example, identical twins raised in separate environments often have similar body types. Most cases of human obesity are attrib-uted mainly to the combination of genetic susceptibility and environmental conditions.

Environmental FactorsEnvironmental factors contributing to the greater number of overweight and obese individuals include increased food con-sumption and decreased physical activity. The ready availabil-ity and relatively low cost of a wide variety of foods, in addition to large portion sizes and high-calorie foods, promote overeat-ing. In addition, many social gatherings are associated with eat-ing or overeating.

In relation to physical activity, the usual activities of daily household maintenance living for many people, including work-related activities, require relatively little energy expendi-ture. In addition, few Canadians are thought to exercise in the optimal frequency, intensity, or duration to maintain health and prevent excessive weight gain. For both adults and chil-dren, using a car for transportation, increased time watching television, playing video or computer games, and working on computers contributes to less physical activity and is thought to promote weight gain and obesity. Statistics Canada found a direct correlation between the amount of time young people spent watching TV and playing videogames and their likeli-hood of being overweight or obese.

18.5 indicating underweight and values of 25 or above indi-cating excessive weight (Box 58-1). A large waist circumfer-ence (>88 cm [35 in.] for women, >102 cm [40 in.] for men) is another risk factor for health problems such as type 2 diabetes, coronary heart disease (CHD), and hypertension. Waist to hip ratio (WHR) is also used by health professionals to estimate the distribution of fat and it indicates increased risk when mea-surements approximate these levels.

Obesity may occur in anyone but is more likely to occur in women, minority groups, and poor people. It results from consistent ingestion of more calories than are used for energy and it substantially increases risks for development of numer-ous health problems (Box 58-2). Most obesity-related disorders are attributed mainly to the multiple metabolic abnormali-ties associated with obesity. Abdominal fat out of proportion to total body fat (also called central or visceral obesity), which often occurs in men and postmenopausal women, is considered a greater risk factor for disease and death than lower body obe-sity. In addition to the many health problems associated with obesity, obesity is increasingly being considered a chronic dis-ease in its own right. Although it has been the focus of much research in recent years, no current theory adequately explains the disorder and its resistance to treatment.

PrevalenceThe prevalence of overweight people and obesity has dramati-cally increased over the past 20 years. Some authorities estimate that approximately 30% of Canadian adults are overweight or obese. There are differences in prevalence by gender, ethnicity, and socioeconomic status. In general, more women than men are obese, whereas more men than women are overweight; and women in lower socioeconomic classes are more likely to be obese than those women in higher socioeconomic classes.

EtiologyThe etiology of excessive weight is thought to involve complex and often overlapping interactions among physiologic, genetic, environmental, psychosocial, and other factors.

Box 58-1 Calculation of BMI

BMI

BMI can be calculated as weight in kilograms divided by height in metres squared, as follows:

BMI = weight (kg)height (m)2

Example: A person who weighs 68.18 kg and is 162.5 cm tall68.2

(1.63)2

68.2 = 25.64(2.66)


Chapter 58 Drugs to Aid Weight Management ■ 939

Box 58-2 Health Risks of Obesity

Obesity is associated with serious health risks. Several disease states and chronic health problems, as well as increased mortal-ity, are more prevalent in obese patients. Studies indicate that a high BMI is associated with an increased risk of death from all causes, among both men and women, and in all age groups. In addition, a higher death rate occurs in people who gain weight of 10 kg or more after 18 years of age. Some of the major health risks include the disorders listed below. In general, these conditions tend to worsen as the degree of obesity increases and improve with weight loss.

Cancer

Obesity is associated with a higher prevalence of breast, colon, and endometrial cancers. With breast cancer, risks increase in postmenopausal women with increasing body weight. Women who gain >10 kg from age 18 to midlife have double the risk of breast cancer compared with women who maintain a stable weight during this period of their life. In addition, central obesity apparently increases the risk of breast cancer indepen-dent of overall obesity. In women with central obesity, this additional risk factor may be related to an excess of estrogen (from conversion of androstenedione to estradiol in peripheral fatty tissue) and a defi ciency of sex hormone–binding globulin to combine with the estrogen.

Colon cancer seems to be more common in obese men and women. In addition, a high BMI may be a risk factor for a higher mortality rate with colon cancer. Endometrial cancer is clearly more common in obese women, with adult weight gain again increasing risk.

Cardiovascular Disorders

Obesity is a major risk factor for cardiovascular disorders and increased mortality from cardiovascular disease. Studies have confi rmed the relationship between obesity and increased risk of CHD and stroke in both men and women. In addition, obesity during adolescence is associated with higher rates and greater severity of cardiovascular disease as adults.

Obesity increases risks by aggravating other risk factors such as hypertension, insulin resistance, low HDL cholesterol, and hypertriglyceridemia. In addition, obesity seems to be an independent risk factor for cardiovascular disorders, and central obesity may be more important than BMI as a risk factor for death from cardiovascular disease. The increased mortality rate is seen even with modest excess body weight.

Hypertension, dyslipidemia, insulin resistance, and glucose intolerance are known cardiac risk factors that tend to clus-ter in obese individuals. Hypertension often occurs in obese persons and is thought to play a major role in the increased incidence of cardiovascular disease and stroke observed in patients with obesity. Metabolic abnormalities that occur with obesity and type 2 diabetes mellitus (eg, insulin resistance and the resultant hyperinsulinemia) aggravate hypertension and increase cardiovascular risks. The combination of obesity and hypertension is associated with cardiac changes (eg, thickening of the ventricular wall, ischemia, and increased heart volume)

that lead to heart failure more rapidly. Weight loss of as little as 4.5 kg (10 lb) can decrease blood pressure and cardiovascular risk in many people with obesity and hypertension.

Diabetes Mellitus

Obesity is strongly associated with impaired glucose tolerance, insulin resistance, and diabetes mellitus. In addition, obesity during adolescence is associated with higher rates of diabetes as adults as well as more severe complications of diabetes at younger ages.

The cellular effects by which obesity causes insulin resis-tance are unknown. Proposed mechanisms include down regulation of insulin receptors, abnormal postreceptor signals, and others. Whatever the mechanism, the impaired insulin response stimulates the pancreatic beta cells to increase insulin secretion, resulting in a relative excess of insulin called hyper-insulinemia, and causes impaired lipid metabolism (increased LDL cholesterol and triglycerides and decreased HDL). These metabolic changes increase hypertension and other risk factors for cardiovascular disease. As with cardiovascular disease and diabetes in general, central obesity seems to increase the likeli-hood of serious disease. The abdominal fat of central obesity seems to be more insulin resistant than peripheral fat deposited over the buttocks and legs. Intentional weight loss signifi cantly reduces mortality in obese individuals with diabetes.

Dyslipidemias

Obesity strongly contributes to abnormal and undesirable changes in lipid metabolism (eg, increased triglycerides and LDL cholesterol; decreased HDL cholesterol) that increase risks of cardiovascular disease and other health problems.

Gallstones

Obesity apparently increases the risk for developing gallstones by altering production and metabolism of cholesterol and bile. The risk is higher in women, especially those who have had multiple pregnancies or who are taking oral contraceptives. However, rapid weight loss with very low calorie diets is also associated with gallstones.

Metabolic Syndrome

Metabolic syndrome is a group of risk factors and chronic conditions that occur together and greatly increase the risks of diabetes mellitus, serious cardiovascular disease, and death. The syndrome is thought to be highly prevalent in North America. Major characteristics include many of the health problems associated with obesity (eg, dyslipidemias, hyperten-sion, impaired glucose tolerance, insulin resistance, central obesity). More specifi cally, metabolic syndrome includes three or more of the following abnormalities:

■ Central obesity (waist circumference > 102 cm [40 in.] for men and >88 cm [35 in.] for women)

■ Serum triglycerides of 1.7 mmol/L or more




Psychosocial FactorsPsychosocial disorders may be either a cause or an effect of obe-sity. Although much is still unknown about the psychological aspects of obesity development, depression and/or abuse may play a role. Obese people often report symptoms of depression and some people overeat and gain weight during depressive epi-sodes. It may be that obesity and depression commonly occur together and reinforce each other. A depressed person is less likely to take the active measures in diet and exercise that are required to lose weight, even if obesity is a prominent factor in the development of depression. In women, sexual, physical, and emotional abuse can result in obesity. Abuse during child-hood and adolescence tends to produce more severe effects.

Other FactorsDiseases are rarely a major cause of obesity development. How-ever, numerous disease processes may limit a person’s ability to engage in calorie-burning physical activity. In addition, numer-ous prescription medications reportedly cause weight gain in some or most of the patients who take them (Box 58-3).

Overweight and Obese ChildrenBeing overweight and obesity are common and increasing among children and adolescents, in a similar dramatic fashion as Canadian adults. Overweight is defi ned as a BMI above the 85th percentile for the age group, and obesity as a BMI above the 95th percentile.

Childhood obesity is a major public health concern because these children have or are at risk of developing hypertension, dyslipidemias, type 2 diabetes, and other disorders that may lead to major disability and death at younger adult ages than nonobese children. Obesity, type 2 diabetes, and other health problems are mainly attributed to poor eating habits and too little exercise. In addition, the child who is obese after 6 years of age is highly likely to be obese as an adult, especially if a par-ent is obese. Obesity in adults that began in childhood tends to be more severe.

In addition to major health problems, reduced energy, and less physical agility, obese children are often ridiculed or bullied by other children and may be discriminated against by adults in schools and workplaces.

General Characteristics of Drugs for Obesity

Most organizations generally recommend reserving drug therapy for those with a BMI of 30 kg per m2 or greater and health prob-lems (eg, hypertension, dyslipidemia, CHD, type 2 diabetes, sleep apnea) that are likely to improve with weight loss. Drug therapy for obesity should be used as part of a weight- management pro-gram that also includes a sensible diet, physical activity, and behavioural modifi cation. Guidelines also emphasize that drug

Box 58-2 Health Risks of Obesity (continued)

■ HDL cholesterol < 1.0 mmol/L in men and <1.3 mmol/L in women

■ Blood pressure of 130/85 mm Hg or higher■ Fasting serum glucose of 6.2–7.0 mmol/L or higher

Osteoarthritis

Obesity is associated with OA of both weight-bearing joints, such as the hip and knee, and non–weight-bearing joints. Extra weight can stress affected bones and joints, contract muscles that normally stabilize joints, and may alter the metabolism of cartilage, collagen, and bone. In general, obese people develop OA of the knees at an earlier age and are more likely than nonobese people to require knee replacement surgery.

The important role of obesity in OA is supported by the observation that weight loss delays onset and reduces symptoms and disability. Weight reduction may also decrease infection, wound complications, and blood loss if surgery is required. Despite the benefi ts of weight loss, however, persons with OA have diffi culty losing weight because painful joints limit exer-cise and activity.

Sleep Apnea

Sleep apnea commonly occurs in obese persons. A possible explanation is enlargement of soft tissue in the upper airways

that leads to collapse of the upper airways with inspiration during sleep. The obstructed breathing leads to apnea with hypoxemia, hypercarbia, and a stress response. Sleep apnea is associated with increased risks of hypertension, possible right heart failure, and sudden death. Weight loss leads to improve-ment in sleep apnea.

Miscellaneous Effects

Obesity is associated with numerous diffi culties in addition to those described above. These may include:

■ Nonalcoholic fatty liver disease, which is being increas-ingly recognized and which may lead to liver failure

■ Poor wound healing■ Poor antibody response to hepatitis B vaccine■ A negative perception of people who are obese that affects

their education, socioeconomic, and employment status■ High costs associated with treatment of the medical condi-

tions caused or aggravated by obesity as well as the costs associated with weight-loss efforts

■ In women, obesity is associated with menstrual irregularities and increased complications of pregnancy (eg, gestational diabetes, higher rates of labour induction and caesarean section, and increased risk of neural tube and other congenital defects in offspring of obese women).



Box 58-3 Effects of Selected Medications on Weight

Anti-Depressants

SSRIs, such as fl uoxetine (Prozac) and related drugs, appar-ently promote weight loss with short-term use. However, with long-term use, they reportedly may cause as much weight gain as TCAs such as amitriptyline (Elavil). TCAs have long been associated with excessive appetite and weight gain. Mirtazapine (Remeron) and phenelzine (Nardil) are also associated with weight gain. The effects of bupropion (Wellbutrin, Zyban) on weight are unclear from clinical trials; however, anorexia and weight loss occurred at a higher percentage rate than increased appetite and weight gain.

Anti-Diabetic Drugs

Although little attention is paid to the topic in most litera-ture about diabetic drugs, weight gain occurs with insulin, sulphonylureas, and the glitazones (but not with metformin [Glucophage] or acarbose [Prandase]). Almost all patients with type 2 diabetes eventually require insulin; those who are fail-ing on oral agents generally gain a large amount of body fat when switched to insulin therapy. Although the mechanism of weight gain is unknown, it may be related to the chronic hyperinsulinism induced by long-acting insulins and the sul-phonylureas (which increase insulin secretion). Less weight is gained when oral drugs are given during the day and intermedi-ate- or long-acting insulin is injected at bedtime. This strategy is thought to cause less daytime hyperinsulinemia than the more traditional insulin strategies.

For near–normal-weight diabetic patients who require drug therapy, a sulphonylurea may be given. However, for obese patients, metformin is usually the initial drug of choice because it does not promote weight gain.

Anti-Epileptic Drugs

Weight gain commonly occurs with the use of anti-epileptic drugs (AEDs). This has been observed for many years with older drugs (eg, phenytoin, valproic acid [Epival, Depakene], carbamazepine [Tegretol]) and more recently with newer AEDs (eg, gabapentin [Neurontin], lamotrigine [Lamictal]). Mecha-nisms by which the drugs promote weight gain are unclear, but may involve stimulation of appetite and/or a slowed metabolic rate. Consequences of weight gain may include increased risks of diabetes mellitus, hypertension, and other physical health problems as well as psychological distress over appearance, especially in children and adolescents.

Anti-histamines

Histamine1 (H1) antagonists (eg, diphenhydramine [Benadryl], loratadine [Claritin]) reportedly increase appetite and cause weight gain.

Anti-Hypertensives

The main anti-hypertensive drugs reported to cause weight gain are the widely used beta-blockers. The drugs can cause fatigue and decrease exercise tolerance and metabolic rate, all

of which may contribute to weight gain. Other mechanisms may also be involved. As a result, some clinicians question the use of beta-blockers in overweight or obese patients with uncomplicated hypertension. Alpha-blockers may also cause weight gain, but apparently at a low incidence of 0.5%–1%. Angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers are not reported to promote weight gain.

Anti-Psychotics

Weight gain is often reported and extensively documented with the use of atypical drugs, the most commonly used anti-psychotic drugs. Although the exact mechanism is unknown, weight gain has been associated with anti-histaminic effects, anti-cholinergic effects, and blockade of serotonin receptors. In addition, dietary factors and activity levels may also play signifi cant roles.

Clozapine (Clozaril) and olanzapine (Zyprexa) can cause signifi cant weight gain in 40% or more of patients. Compared with clozapine and olanzapine, risperidone causes less weight gain, and quetiapine (Seroquel) causes the least weight gain. Weight gain may lead to noncompliance with drug therapy. In addition to weight gain, clozapine and olanzapine adversely affect glucose regulation and can aggravate pre-existing dia-betes or cause new-onset diabetes. The extent to which these effects are related to weight gain is unknown. Typical anti-psychotics (such as chlorpromazine) also cause weight gain.

Cholesterol-Lowering Agents

Weight gain has been reported with the statin group of drugs; mechanisms and extent are unknown.

Corticosteroids

Systemic corticosteroids may cause increased appetite, weight gain, central obesity, and retention of sodium and fl uid. Inhaled and intranasal corticosteroids have little effect on weight.

Gastrointestinal Drugs

Increased appetite and weight gain have been reported with the proton pump inhibitors (PPIs) such as omeprazole (Losec) and others. The mechanisms and extent are unknown.

Hormonal Contraceptives

The weight gain associated with using hormonal contracep-tives may be related more to retention of fl uid and sodium than to increased body fat.

Mood Stabilizing Agent

Weight gain has been reported with long-term use of lithium, with approximately 20% of patients gaining 10 kg or more. This increased weight is attributed to fl uid retention, consump-tion of high-calorie beverages as a result of increased thirst; or a decreased metabolic rate. Weight gain is a common reason for noncompliance with lithium therapy and weight gain may be more common in women with lithium-induced hypothyroidism and in those who are already overweight.



or agitation because of CNS stimulant effects. The most com-monly reported adverse effects are nervousness, dry mouth, constipation, and hypertension. As with all weight loss medi-cations, it should be used in conjunction with dietary restric-tions for weight reduction and maintenance.

SibutramineSibutramine (Meridia) inhibits the reuptake of serotonin and norepinephrine in the brain, thereby increasing the amounts of these neurotransmitters. Clinical effects include increased satiety, decreased food intake, and a faster metabolism rate. Sibutramine is approved by Health Canada for long-term use, but effects are mostly unknown beyond 1 year. The drug increases blood pressure and heart rate and is contraindicated in patients with cardiovascular disorders (eg, CHD, dysrhyth-mias, heart failure, hypertension) or psychiatric illness. It should be used cautiously in patients who take other medica-tions that increase blood pressure and pulse rate. It should also be used cautiously in patients with impaired hepatic function, narrow-angle glaucoma (may cause mydriasis), or a history of substance abuse or dependency. Sibutramine has not been stud-ied in children under 18 years of age or in patients over age 65. It is not recommended for women who are pregnant or lactat-ing. The drug is contraindicated in people with severe renal or hepatic dysfunction.

Oral sibutramine is rapidly absorbed from the intes-tine and undergoes fi rst-pass metabolism, during which time active metabolites are formed. Peak plasma levels of the active metabolites occur within 3 to 4 hours and drug half-life is 14 to 16 hours. The long half-lives of the active metabolites allow for once-daily dosing. The drug is highly bound to plasma proteins and rapidly distributed to most body tissues, with the highest concentrations in the liver and kidneys. It is metabolized in the liver, mainly by the cytochrome P450 3A4 enzymes. The active metabolites produced by fi rst-pass metabolism are further metabolized to inactive metabolites, which are then excreted in urine and feces.

Common adverse effects of sibutramine include dry mouth, headache, insomnia, nervousness, and constipation; cardiovascular effects include hypertension, tachycardia, and

therapy should be used to decrease medical risk and improve health rather than promote cosmetic weight loss.

Drug therapy for obesity has a problematic history, mainly because of serious adverse effects and rapid weight regain when the drugs were stopped. The drug, phenylpropanolamine, and the components of many over-the-counter and herbal weight-loss products, ephedra and ma huang, have been taken off the market because of their adverse effects.

Older drugs include amphetamines and similar drugs. Amphetamines (see Chap. 15) are not recommended because they are controlled substances with a high potential for abuse and dependence. Diethylpropion (Tenuate) and phen-termine (Ionamin) are adrenergic drugs (see Chap. 17) that stimulate the release of norepinephrine and dopamine in the brain. This action in nerve terminals of the hypothalamic feed-ing centre suppresses appetite. These drugs are central nervous system (CNS) and cardiovascular stimulants and are contrain-dicated in cardiovascular disease, hyperthyroidism, glaucoma, and agitated states.

Of the adrenergic anorexiant drugs, only phentermine is commonly used. Two newer drugs, sibutramine (Meridia) and orlistat (Xenical), are more commonly used and are the only weight-loss drugs approved for long-term use. According to some clinicians, sibutramine and orlistat may be continued as long as they are effective and adverse effects are tolerable. The drugs are described below; dosage ranges are listed in Table 58-1.

Individual Drugs

PhenterminePhentermine hydrochloride (Ionamin) is the most frequently prescribed adrenergic anorexiant. It is a controlled drug and recommended only for short-term use (3 months or less). Its use is contraindicated in patients with hypertension or other cardiovascular disease and in those with a history of drug abuse. Because it increases blood pressure, phentermine should be used with caution even in patients with mild hypertension. The drug should also be used cautiously in patients with anxiety

Drugs at a Glance: Drugs for ObesityTable 58-1

GENERIC/TRADE NAME ROUTE AND DOSAGE RANGES

APPETITE SUPPRESSANTSPhentermine hydrochloride (Ionamin) PO 15–30 mg daily in the morning

Sibutramine (Meridia) PO 10–15 mg once daily, in the morning, with or without food

FAT BLOCKEROrlistat (Xenical) PO 120 mg with each main meal, up to three capsules daily

PO, oral.



fatty, malodourous stools) worsen with high fat consumption. Long-term effects of orlistat are unknown, although one study reported safe and effective use for 2 years. In addition to weight loss and reduced cholesterol levels, clinical trials found reduced severity and improved management of other health problems associated with obesity, such as diabetes and hypertension. In general, the addition of orlistat therapy to diet and other life-style changes produced greater weight loss than the addition of a placebo. In some patients with impaired glucose tolerance, weight loss with orlistat and lifestyle changes prevented or delayed the occurrence of diabetes mellitus. After the medica-tion was stopped, most patients regained weight.

In a new direction, a recent European study found that modulating the activity of the endocannabinoid system by blocking its receptors could reduce weight, waist circumfer-ence, lipid concentrations, and insulin resistance. Further research will need to be done to ensure the validity and reli-ability of these fi ndings.


Pauline asks how orlistat (Xenical) will help her when

nothing else in the past has been successful. How would

you respond?

Natural Health Products

Many people use herbal or dietary supplements for weight loss, even though reliable evidence of safety and effectiveness is lacking. Some herbal products claim to decrease appetite and increase the rate at which the body burns calories. However, in most cases, there is no scientifi c evidence that they work at all. Some supplements for weight loss contain cardiovascular and CNS stimulants that may cause serious, even life-threatening, adverse effects.

In general, many consumers do not seem to appreciate the benefi ts of proven weight-management techniques (eg, appro-priate diet and exercise) or the potential risks of taking unproven weight-loss products. Selected products are described below.

Acai (Euterpe oleracea), a berry from the acai palm tree native to Central and South America, has recently been pro-posed to foster weight loss. Juice from the berry is used for osteoarthritis (OA), hypercholesterolemia, weight loss, and obesity and for improving general health. Research has centred on the anti-oxidant properties rather than weight loss. There is no scientifi c evidence to support its role in weight loss.

Ephedra (ma huang) is an herb that has long been a component of many weight-loss products (eg, Herbalife). It is not recommended for use by anyone because it is a strong cardiovascular and CNS stimulant that increases risks of heart attack, seizure, stroke, and sudden death. Many ephedra- containing products also contained caffeine, which can further increase cardiovascular and CNS stimulation. In 2002, Health

palpitations. Potentially serious drug interactions may occur if sibutramine is taken with other cardiovascular stimulants (increased risk of hypertension and dysrhythmias), CNS stimu-lants (increased anxiety and insomnia), anti-psychotics, and serotonergic drugs (serotonin syndrome). Other drugs that increase serotonin include the selective serotonin reuptake inhibitors (SSRIs) (eg, fl uoxetine [Prozac] and related drugs); St. John’s wort; the triptan anti-migraine drugs (eg, sumatrip-tan [Imitrex]); dextromethorphan (a common ingredient in cough syrups); and lithium. The combination of sibutramine with any of these drugs may cause serotonin syndrome, a condition characterized by agitation, confusion, hypomania, impaired coordination, loss of consciousness, nausea, tachycar-dia, and other symptoms.

In clinical trials, people lost the most weight during the fi rst 6 months of sibutramine therapy. However, continued drug therapy helped to maintain weight loss for 12 to 24 months. Most of the clinical trials included diet and behavioural modi-fi cation techniques in addition to sibutramine therapy. As with other weight-loss drugs, studies indicate that sibutramine ther-apy is more effective when it is combined with lifestyle modifi -cation and diet than when used alone.

OrlistatOrlistat (Xenical) differs from phentermine and sibutramine because it decreases absorption of dietary fat from the intestine (by binding to gastric and pancreatic lipases in the gastrointes-tinal [GI] tract lumen and making them unavailable to break down dietary fats into absorbable free fatty acids and mono-glycerides). The drug blocks the absorption of approximately 30% of the fat ingested in a meal; increasing dosage does not increase this percentage. Decreased fat absorption leads to decreased caloric intake, resulting in weight loss and improved serum cholesterol values (eg, decreased total and low-density lipoprotein [LDL] cholesterol levels). The improvement in cholesterol levels is thought to be independent of weight-loss effects. The use of orlistat has not been studied in pregnant or lactating women.

Orlistat is not absorbed systemically and its action occurs in the GI tract. Consequently, it does not cause systemic adverse effects or drug interactions as phentermine and sibutramine do. Its main disadvantages are frequent administration (three times daily) and GI symptoms (abdominal pain, oily spotting, fecal urgency, fl atulence with discharge, fatty stools, fecal inconti-nence, and increased defecation). Adverse GI effects occur in almost all orlistat users but usually subside after a few weeks of continued drug usage. The drug also prevents the absorption of the fat-soluble vitamins, A, D, E, and K. As a result, peo-ple taking orlistat should also take a multivitamin containing these vitamins daily. The multivitamin should be taken 2 hours before or after the orlistat dose. If taken at the same time, the orlistat prevents the absorption of the fat-soluble vitamins.

Orlistat is intended for people who are clinically obese, not those wanting to lose a few kilograms. In addition, high-fat foods still need to be decreased because total caloric intake is a major determinant of weight, and adverse effects (eg, diarrhea;



to contain an undeclared pharmaceutical ingredient similar to sibutramine.

YGD, a combination of Yerba Maté, Guarana, and Dami-ana in capsule form, was tested in a research study investigating weight loss and delayed gastric emptying. The study published in 2001, demonstrated signifi cant weight loss using YGD cap-sules compared to placebo after 45 days with patients main-taining weight loss while on maintenance treatment of YGD in an uncontrolled context. Delaying of gastric emptying was thought to be a signifi cant contributor to the weight loss.

Canada announced a recall of products containing ephe-dra; it is authorized for use only as an over-the-counter nasal decongestant.

Glucomannan expands on contact with body fl uids. It is included in weight-loss regimens because of its supposed abil-ity to produce feelings of stomach fullness, thereby causing a person to eat less. It also has a laxative effect. There is little evidence to support its use as a weight-loss aid. Products con-taining glucomannan should not be used by people with diabe-tes; glucomannan may cause hypoglycemia alone and increases hypoglycemic effects of anti-diabetic medications.

Guarana, a major source of commercial caffeine, is found in weight-loss products as well as caffeine-containing soft drinks, bodybuilding supplements, smoking-cessation products, vitamin supplements, candies, and chewing gums. Caffeine is the active ingredient; the amount varies among products, and caffeine content of any particular product cannot be accu-rately predicted. Guarana is promoted to decrease appetite and increase energy and mental alertness. It is contraindicated in patients with dysrhythmias and may aggravate gastroesopha-geal refl ux disease (GERD) and peptic ulcer disease.

Adverse effects include diuresis, cardiovascular symptoms (premature ventricular contractions, tachycardia), CNS symp-toms (agitation, anxiety, insomnia, seizures, tremors), and GI symptoms (nausea, vomiting, diarrhea). Such effects are more likely to occur with higher doses or concomitant use of guarana and other sources of caffeine. Adverse drug–drug interactions include additive CNS and cardiovascular stimulation with beta-adrenergic agonists (eg, epinephrine, salbutamol and related drugs, pseudoephedrine) and theophylline. In addition, concurrent use of cimetidine, fl uoroquinolones, or oral con-traceptives may increase or prolong serum caffeine levels and subsequent adverse effects.

Guar gum is a dietary fi bre included in weight-loss prod-ucts because it is bulk-forming and produces feelings of fullness. Several small studies indicated that it is no more effective than a placebo for weight loss. It may cause esophageal or intestinal obstruction if not taken with an adequate amount of water and may interfere with the absorption of other drugs if taken at the same time. Adverse effects include nausea, diarrhea, fl atulence, and abdominal discomfort.

Hydroxycitric acid (in Citrimax and other supplements) apparently suppresses appetite in animals, but there are no reliable studies that indicate its effectiveness in humans. One 12-week study did not show weight loss.

Laxative and diuretic herbs (eg, aloe, rhubarb root, buckthorn, cascara, senna, parsley, juniper, dandelion leaves) are found in several products. Laxative and diuretic herbs can cause a signifi cant loss of body fl uids and electrolytes, not fat. Adverse effects may include low serum potassium levels, with subsequent cardiac dysrhythmias and other heart problems. In addition, long-term use of laxatives may lead to loss of normal bowel function and the necessity for continued use (ie, laxative dependency).

Health Canada is warning Canadians not to use the unau-thorized product, Slim Magic Herbal Weight Loss, as it is found

Nursing Process

AssessmentAssess each overweight or obese patient for factors contribut-ing to overweight and health risks related to excess weight, regardless of the reason for the contact. Some specifi c assess-ment factors include the following:

■ Assess usual drinking and eating patterns, including healthful (eg, whole-grain breads and cereals, fruits, veg-etables, low-fat dairy products) and unhealthy (eg, sugar-containing beverages and desserts, fried foods, saturated fat, fast foods, high-calorie snack foods) intake. The best way is to ask the patient to keep a food diary for 2 or 3 d. If food intake is not written down, people tend to underesti-mate the amount and caloric content. (If available, consult a nutritionist to assess a patient’s diet and work with the patient to improve health and weight status.)

■ Assess any obviously overweight person for health prob-lems caused or aggravated by excessive weight (eg, elevated blood pressure, other cardiovascular problems, diabetes mellitus, sleep apnea).

■ Calculate or estimate the BMI (see Box 58-1) and measure waist circumference.

■ Check available reports of laboratory tests. Overweight patients may have abnormally high values for total and LDL cholesterol, triglycerides, and blood sugar, and low values for high-density lipoprotein (HDL) cholesterol. If no laboratory reports are available, ask patients if a health care provider has ever told them that they have high cho-lesterol or blood sugar.

■ List all prescription and non-prescription medications being taken and ask about vitamins, herbals, and other dietary supplements. Review the list for drugs used to treat health problems associated with obesity, drugs that may promote weight gain, and any products that may be used to promote weight loss.

■ Assess usual patterns of physical activity and exercise, including work and recreational activities.

■ Assess motivation to develop and adhere to a weight-management plan. Ask if there are concerns about weight;



if there is interest in a weight-management program to improve health; and what methods, over-the-counter products, or herbal or dietary supplements have been pre-viously used to reduce weight, if any. The nurse must be very tactful in eliciting information and assessing whether a patient would like assistance with weight management. If the nurse–patient contact stems from a health problem caused or aggravated by excessive weight, the nurse may use this information to help motivate the patient to lose weight and improve health.

Nursing Diagnoses■ Imbalanced nutrition: More than body requirements

related to excessive caloric intake■ Disturbed body image related to excessive weight gain■ Defi cient knowledge: Weight management, participation

in physical activity

Planning/GoalsThe patient will

■ Reduce the impact of excessive weight on chronic health problems

■ Modify lifestyle behaviours toward weight loss and weight maintenance at a more healthful level

■ Increase participation in physical activities■ Take anorexiant drugs only as prescribed■ Describe problems associated with unproven weight-loss

dietary supplements

Interventions■ Support programs/efforts to help promote a healthful life-

style and prevent obesity (eg, in families and schools).■ Serve as a role model by maintaining a healthful lifestyle

and weight.■ Serve as a reliable source of information about weight loss,

weight-loss products and programs, and physical activity (see accompanying Patient Teaching Guidelines).

■ For an obese patient who reports interest and motivation in losing weight, assist to formulate realistic goals. Patients often expect to rapidly lose large amounts of weight with little or no effort. Most treatment programs result in a weight loss of 10% of body weight or less.

■ Discuss health risks of obesity and anticipated benefi ts of achieving and maintaining a healthier weight. Emphasize that losing 5%–10% of body weight is a reasonable goal and can signifi cantly reduce the medical problems associ-ated with being overweight.

■ Assist patients to identify factors that support weight-loss efforts (eg, family and friend encouragement) and factors that sabotage weight-loss efforts (eg, having high-calorie

snack foods readily available, frequently eating at fast-food restaurants).

■ Promote exercise and activity. For overweight and obese patients, exercise may decrease appetite and distract from eating behaviours as well as increase calorie expenditure. For very sedentary, physically unfi t patients, emphasize that any exercise can be benefi cial and to start slowly, increasing the amount and intensity as physical condition improves.

■ Encourage any efforts toward improving diet and increas-ing exercise to improve health.

■ Weigh patients at regular intervals and measure waist circumference periodically.

■ Refer patients to a dietitian when indicated.■ Be alert for the psychological consequences of obesity and

refer patients for counselling if indicated.■ Refer overweight and obese children to pediatric obesity

specialists when possible.

Evaluation■ Assess overweight or obese patients for food intake, weight

loss, decreased waist circumference, and appropriate use of exercise and anorexiant drugs.


In addition to proper administration of her medication,

what strategies should you review with Ms. McKay to assist

her in being successful with weight loss?

Principles of Therapy

Strategies to Prevent Becoming Overweight and ObesePreventing excessive weight gain is a major struggle for many Canadians as they fi ght the “battle of the bulge” daily. Many people want to lose weight, often more for appearance than for health. However, many are also unwilling or unable to adapt their lifestyles toward more healthful eating, exercising, and weight-controlling habits. As a result, millions of dollars are spent annually on weight-loss diets, products, and programs in an effort to fi nd an easy way to lose weight. Health care provid-ers need to promote efforts to prevent overweight and obesity when possible. When prevention is not possible, efforts should be aimed toward early recognition and treatment, before obesity and major health problems develop. Some strategies include the following:

■ Personally practice a healthful lifestyle, primarily for one’s own health and well-being, but also to serve as a role model and proponent for healthful practices in daily life.



Weight Management and Drugs That Aid Weight Loss

General Considerations■ Because of the extensive health problems associated with

overweight and obesity, individuals whose weight is within a normal range should try to prevent excessive weight gain by practicing a healthful lifestyle in terms of diet and exer-cise. Following are useful recommendations:1. Eat a variety of foods daily (eg, 6–8 servings of grain

products; 7–10 servings/d of vegetables and fruit; milk products, servings/d: children 4–9 y: 2, youth 9–18 y: 3–4, adults: 2; meat and alternatives, 2–3 servings/d). Also limit the intake of saturated fat (eg, in meats), trans fats (eg, hydrogenated oils in many commercial baked goods and other products), cholesterol, added sugars, salt, and alcohol. The amount of trans fat in commercial products must be added to the Nutrition Facts label and many manufacturers are reformulating their products with-out trans fats. Canola oil and olive oil are healthy fats, but they have a high calorie content (120 cal/tablespoon [15 mL]), which must be considered in weight control efforts.

2. To maintain body weight in a healthy range, balance diet (ie, calories gained) with exercise (ie, calories used). To prevent gradual weight gain over time, make small decreases in food and beverage calories and increase physical activity. Engage in regular physical activity and reduce sedentary activities to promote health, psycho-logical well-being, and a healthy body weight. To reduce the risk of chronic disease, engage in at least 30–60 min of moderate-intensity physical activity, above usual activ-ity, at work or home on most days of the week. For most people, greater health benefi ts can be obtained by engag-ing in physical activity of more vigorous intensity or longer duration.

3. Physical fi tness can be developed or improved by includ-ing cardiovascular conditioning, stretching exercises for fl exibility, and resistance exercises or calisthenics for muscle strength and endurance.

■ Individuals who are already overweight or obese should try to lose weight and maintain a lower weight because the likelihood of serious health problems and early death increases as weight increases. However, try to emphasize goals for improvement in health status rather than losing a large amount of weight. Remember that even a modest weight loss of 4.5–13 kg (10–30 lb) can benefi t your health. Most people are unlikely to achieve their “ideal” weight, and having unrealistic expectations sets one up for failure in any weight-loss program.

■ Obesity is considered a chronic disease that requires long-term treatment, much like the treatment of diabetes and hypertension. Weight loss can be induced by severe calorie restriction, but without lifestyle changes (eg, in eating and activity behaviour), body fat is invariably regained. The safest and most effective way to lose weight and keep it off is permanent lifestyle changes that involve eating less and exercising more. Reducing caloric intake by 500–1,000 cal/d allows the loss of 0.5–1 kg (1–2 lb) of fat/week, respec-tively. Higher levels of physical activity can help with weight loss and prevent weight regain. Additional health benefi ts include lower rates of cardiovascular disease and death.

■ Use available resources. For example, if unable to imple-ment needed changes alone, consult a dietitian, qualifi ed obesity expert, or behavioural therapist. Such clinicians can help modify the eating, activity, and thinking habits that predispose to obesity.

■ In addition to feeling better, health benefi ts of weight loss may include reduced blood pressure, reduced blood fats, less likelihood of having a heart attack or stroke, and less risk for development of diabetes mellitus.

■ Any weight loss program should include a nutritionally adequate diet with decreased calories and increased exercise.

■ Regular physical examinations and follow-up care are needed during weight loss programs.

■ Although many weight-loss supplements are available and heavily advertised in newspapers, magazines, and televi-sion, none are considered safe and effective and none are recommended for use. If you do choose to use any of these products, notify your primary health care provider. Depend-ing on your condition (ie, whether you have chronic health problems such as diabetes mellitus, hypertension, or oth-ers), the medications you take, and so forth, some weight-loss supplements can be harmful to your health.

■ Diet and exercise are recommended for people who want to lose weight. Medications to aid weight loss are usually recommended only for people whose health is endangered (ie, those who are overweight and have other risk factors for heart disease and those who are obese).

■ Read package inserts and other available information about the drug being taken, who should not take the drug, instruc-tions and precautions for safe usage, and so forth. Keep the material for later reference if questions arise. If unclear about any aspect of the information, consult a health care provider before taking the drug.

■ Appetite-suppressant drugs must be used correctly to avoid potentially serious adverse effects. Because most of these drugs stimulate the heart and the brain, adverse effects may include increased blood pressure, fast heartbeat, irregular heartbeat, heart attack, stroke, dizziness, nervousness, insomnia (if taken late in the day), and mental confusion. In addition, prolonged use of prescription drugs may lead to psychological dependence.

■ Avoid over-the-counter decongestants, allergy, asthma, and cold remedies, and weight-loss herbal or dietary supple-ments when taking a prescription appetite suppressant. The combination can cause serious adverse effects from exces-sive heart and brain stimulation.

■ Inform health care providers when taking an appetite suppressant, mainly to avoid other drugs with similar effects.

■ Orlistat (Xenical) is not an appetite suppressant and does not cause heart or brain stimulation. It works in the intes-tines to keep fats in foods from being absorbed. It should be taken with a low-fat diet. Adverse effects include fatty stools and bloating.

Self-Administration■ Take appetite suppressants in the morning to decrease

appetite during the day and avoid interference with sleep at night.



■ Do not crush or chew sustained-release products.■ With sibutramine (Meridia)

■ Take once daily, with or without food.■ Have blood pressure and heart rate checked at regular

intervals, eg, monthly (the drug increases them).■ Notify a health care provider if a skin rash, hives, or other

allergic reaction occurs.■ With orlistat (Xenical)

■ Take one capsule with each main meal or up to 1 h after a meal, up to three capsules daily. If you miss a meal or eat a meal with no fat, you should omit a dose of orlistat.

■ Take a multivitamin containing fat-soluble vitamins (A, D, E, and K) daily, at least 2 h before or after taking orlistat. Orlistat prevents absorption of fat-soluble vita-mins from food or multivitamin preparations if taken at the same time.

■ Provide or assist others to obtain reliable information about healthful lifestyle habits. For example, Health Canada pub-lishes Eating Well with Canada’s Food Guide and Canadian Guidelines for Healthy Weights as well as numerous other guides related to healthy living and physical activity, which are available online at http://www.hc-sc.gc.ca. The WHO Weight Classifi cation System uses similar categories to assess weight. Selected recommendations include the following:■ Eat a variety of foods from each food group daily

(eg, 6 to 8 servings per day of whole-grain bread and cereals; 7 to 10 servings per day of vegetables and fruit; 2 servings per day of milk products for adults; 2 to 3 serv-ings per day of meat and alternatives). Also limit intake of saturated fat (eg, in meats, cheeses), trans fats (eg, hydro-genated oils in many baked goods), cholesterol, added sugars, salt, and alcohol. Nutrition labelling became mandatory for most prepackaged foods in December, 2005, and the list of ingredients and any health claims must be listed. For example, the amount of trans fat in commercial products must be listed on the label, mov-ing many manufacturers to reformulate their products without trans fats. Canola oil and olive oil are healthy fats, but they have 120 cal per tablespoon, which must be considered in weight-control efforts).

■ To maintain body weight in a healthy range, balance diet (ie, calories gained) with exercise (ie, calories used). To prevent gradual weight gain over time, make small decreases in food and beverage calories and increase physical activity. Engage in regular physical activity and reduce sedentary activities to promote health, psy-chological well-being, and a healthy body weight. To reduce the risk of chronic disease, engage in at least 30 to 60 minutes of moderate-intensity physical activity, above usual activity, at work or home on most days of the week. For most people, greater health benefi ts can be obtained by engaging in physical activity of more vigor-ous intensity or longer duration. For further information on physical activity see http://www.phac-aspc.gc.ca.

In addition to these recommendations, many books, magazine and newspaper articles, and Internet sites (Box 58-4) contain useful information. However, all of these resources are not equally reliable; they must be carefully evaluated.

Box 58-4 Web Sites for Information on Nutrition and Weight Loss

Alberta Agriculture, Food, and Rural Development (www.agric.gov.ab.ca)

Canadian Institutes of Health Research (CIHR) Obesity Research in Canada (www.cihr.irsc.gc.ca/e/20406.html)

Canadian Inventory of Nutrition and Dietetic Associated Research (www.dietitians.ca)

Canadian Medical Association (www.cmaj.ca/misc/obesity/index.shtml)

Centre for Chronic Disease Prevention and Control (www.phac-aspc.gc.ca/ccdpc-cpcmc/)

Health Canada (www.hc-sc.gc.ca/index-eng.php)Food Safety Network (www.foodsafetynetwork.ca)International Obesity Task Force (www.iotf.org)National Centre for Complementary and Alternative

Medicine (NCCAM) (www.nccam.nih.gov)National Heart, Lung, and Blood Institute and the North

American Association for the Study of Obesity. The Practical Guide: Identifi cation, Evaluation, and Treat-ment of Overweight and Obesity in Adults (www.nhlbi.nih.gov/guidelines/obesity/practgdc.htm)

National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Disease: Weight Control Network (www.niddk.nih.gov/HealthEducation/HealthNutrition.htm)

Natural Medicines Comprehensive Database (www.naturaldatabase.com)

RNAO Nursing Best Practice Guidelines Program (www.rnao.org)

Weight Watchers (www.weightwatchers.ca/Index.asp)

Management of Overweight and Obese PatientsTreatment options for obesity include diet, exercise, behavioural modifi cation, drug therapy, and, if these options fail, possibly referring a patient for bariatric (weight-loss) surgery. The safest and most effective treatment for most people usually includes a combination of diet, exercise, and behavioural modifi cation. Drug therapy and bariatric surgery are recommended only for


http://www.hc-sc.gc.ca

http://www.phac-aspc.gc.ca

http://www.agric.gov.ab.ca

http://www.cihr.irsc.gc.ca/e/20406.html

http://www.dietitians.ca

http://www.cmaj.ca/misc/obesity/index.shtml

http://www.cmaj.ca/misc/obesity/index.shtml

http://www.phac-aspc.gc.ca/ccdpc-cpcmc/

http://www.hc-sc.gc.ca/index-eng.php

http://www.foodsafetynetwork.ca

http://www.iotf.org

http://www.nccam.nih.gov

http://www.nhlbi.nih.gov/guidelines/obesity/practgdc.htm

http://www.niddk.nih.gov/HealthEducation/HealthNutrition.htm

http://www.niddk.nih.gov/HealthEducation/HealthNutrition.htm

http://www.naturaldatabase.com

http://www.rnao.org

http://www.weightwatchers.ca/Index.asp


seriously overweight people with major medical problems that can be improved by weight loss. In addition, neither of these treatments is a substitute for the necessary changes in eating and physical activity patterns.

The Centre for Chronic Disease Prevention and Control (CCDPC) provides recommendations for prevention and con-trol of a range of chronic diseases. Recommendations include the following:

■ Weight loss to reduce health problems of individuals: decrease blood pressure if hypertensive; lower elevated lev-els of total cholesterol, LDL cholesterol, and triglycerides, and raise low levels of HDL cholesterol if dyslipidemic; lower elevated blood glucose levels in persons with type 2 diabetes.

■ Use the BMI to assess overweight and obesity and esti-mate disease risks. Measure waist circumference initially and periodically to assess abdominal fat content. Weigh regularly to monitor body weight for gain, loss, or mainte-nance—whether or not the person is involved in a weight-loss program.

■ The initial goal of weight-loss therapy should be to reduce body weight by about 10 percent from baseline, at a rate of 0.05 to 1 kg (1 to 2 lb) per week for a period of 6 months. It is important to determine if the goal is realistic and if the goal can be maintained. A 4.5 kg weight loss has important effects on blood pressure and lipid values. Steady weight loss over a longer period reduces fat stored in the body, limits the loss of vital protein tissues, and avoids the sharp decline in metabolic rate that accompanies rapid weight loss. After weight loss, weight maintenance should be the priority goal because weight regain is a problem with all weight-loss pro-grams. In some cases, after a period of weight maintenance, additional losses may be desirable.

■ Dietary recommendations include creating an energy defi cit based on restricted energy intake or energy expenditure or both. Low-calorie diets for weight loss reduce caloric intake by 500 to 1,000 cal daily. A moderate defi cit diet of 1,200 to 1,500 kcal per day for females and 1,400 to 2,000 kcal per day for males is suggested. Reducing dietary fat can reduce calories. However, reducing dietary fat without reducing total caloric intake does not produce weight loss. Vitamin and mineral supplements that meet age- related require-ments are usually recommended with weight-loss programs that provide less than 1,200 kcal for women or 1,800 kcal for men.

■ Physical activity recommendations should be part of any weight-management program because physical activity contributes to weight loss, may decrease abdominal fat, increases cardiorespiratory fi tness, and helps with weight maintenance. Initially, physical activity for 30 to 45 min-utes, 3 to 5 days a week, is encouraged. Long-term, adults should try to accumulate at least 30 minutes or more of mod-erate-intensity physical activity on most days of the week.

■ In general, lifestyle change strategies support decreased food intake, increased physical activity, and behaviour programs.

After weight loss, weight-loss maintenance with dietary therapy, physical activity, and behaviour therapy should be continued indefi nitely. Drug therapy can also be used, but the Public Health Agency of Canada, CCDPC, does not suggest using this therapy.

■ Behavioural modifi cation is an integral part of a weight-loss program. The goals of behavioural programs are to help patients modify their eating, activity, and thinking habits that predispose to obesity. Techniques include identifying triggers that promote overeating and barriers that keep one from adopting a more healthful lifestyle. One strategy is keeping an accurate record of food/calorie intake and physi-cal activity (most people tend to underestimate food intake and overestimate activity). In addition, stress management with techniques such as relaxation and meditation, stimu-lus control, and social support for reinforcement of positive changes are helpful. Patients who eat more when stressed can learn to manage stress more healthfully. Counselling by a behavioural therapist may be needed. Stimulus control has to do with avoiding or minimizing circumstances that promote overeating (eg, cooking calorie-dense foods; hav-ing high-calorie snacks and “junk food” readily available; eating high-fat, high-calorie foods at fast-food restaurants). Social support involves family, friends, coworkers, and fel-low dieters who encourage weight-loss efforts rather than sabotage them by urging one to eat high-calorie foods. In general, weight-loss regimens that use several of these strat-egies seem to be most effective.

In addition to the CCDPC guidelines, additional recommenda-tions and comments include the following:

■ Emphasize health benefi ts of weight reduction. There is strong evidence that weight loss reduces risk factors for car-diovascular disease, including blood pressure, serum triglyc-erides, and total and LDL cholesterol. It also increases HDL cholesterol. In addition, in overweight and obese people without diabetes, weight loss reduces blood glucose levels and the risk for development of type 2 diabetes.

■ For people who already have type 2 diabetes, weight loss reduces blood levels of glucose and glycosylated (A1c) hemoglobin. These effects make the diabetes easier to man-age, reduce complications of diabetes, and may allow smaller doses of anti-diabetic medications. For people who already have hypertension, losing excess weight reduces blood pres-sure and may reduce the number or amount of anti-hyper-tensive drugs. For people who already have dyslipidemias, blood lipid profi les improve with weight loss.

■ Weight-loss diets wax and wane in popularity with the North American public (Box 58-5). Although all of them can lead to weight loss if adhered to long enough, some are healthier than others, and most are discarded before signifi cant weight loss is achieved. Actually, any diet that reduces caloric intake in relation to caloric expenditure can lead to weight loss, and adherence is probably more important than the particular diet unless specifi c restrictions result in nutritional defi cien-cies. Regardless of what some diet gurus and others say, total



Box 58-5 Characteristics of Selected Diets

Various diets all work if total caloric intake is less than energy expenditure. Many diets are quite restrictive, however, and most people soon drop out and rapidly regain the weight they lost. As a result, the best “diet” is nutritionally adequate except for calories and can be followed long term.

Low calorie. These diets provide about 1,200–1,600 kcal/d. The usual recommendation is to reduce caloric intake by 500–1,000 cal daily, to allow weight loss of 0.5–1 kg weekly. This rate of loss is likely to be more successful in terms of weight loss, and continuing a reduced-calorie diet promotes weight maintenance rather than weight regain. Note that losing weight through diet alone, without increased physical activity, is unlikely to improve cardiovascular health.

Very low calorie. These diets usually consist of 800 cal or fewer per day. Numerous commercial products that promise “magical” results have been marketed. These diets result in rapid initial weight losses due mainly to diuresis and loss of sodium and water. Multiple health risks accompany such diets, including abnormalities in electrolytes, trace elements, and vitamins; gout; gallstones; cold intolerance; fatigue; light-head-edness; anemia; menstrual irregularities; and other problems.

It is not recommended to use diets that provide fewer than 800 cal daily. If used at all, very low calorie diets should be used intermittently, for short periods, with a diet that maintains weight and is more nutritionally adequate.

Low fat. These diets do not cause signifi cant weight loss unless caloric intake is reduced. Because fats are energy dense (9 cal/g), reducing fat is a practical way to reduce caloric intake. For both, health and weight loss, current recommenda-tions emphasize reducing intake of “bad” fats (eg, saturated and trans fat) but including healthy monounsaturated and poly-unsaturated fats (eg, olive and canola oil) within the caloric allotment.

The weight loss that occurs with these diets is attributed to caloric reduction or water loss, rather than the carbohydrate restriction. There have been no studies evaluating the long-term safety of low-carbohydrate diets.

The Atkins diet is a high-fat, low-carbohydrate diet consist-ing of unlimited amounts of meat, fi sh, eggs, and some cheeses. Sweets, starchy snacks, many fruits, some starchy vegetables, and some grains are prohibited. The high-protein foods cause a feeling of satiety with less food, so fewer calories are consumed. Also, during the fi rst 10 d of this diet, ketosis is induced (by burning fat for energy when carbohydrates are not available). Ketosis increases water loss, which can cause rapid weight loss initially. Then, weight loss occurs more slowly. The main prem-ise of this diet is that carbohydrates increase insulin levels and induce metabolic changes that cause weight gain. Although the Atkins diet seems to cause more short-term weight loss than traditional low-fat diets, weight loss is similar with the two diets after a year.

The South Beach diet is an adaptation of the Atkins diet. This diet emphasizes “good” versus “bad” carbohydrates and the “glycemic index.” The glycemic index indicates the effect of foods on blood glucose levels. Some carbohydrates with a high glycemic index (eg, potatoes, pasta, white rice, white bread) can increase blood glucose as much as or more than similar amounts of sucrose. The elevated blood sugar level stimulates increased insulin secretion and leads to excessive insulin in the blood. In general, high glycemic index foods are thought to promote fat accumulation and obesity. Low glycemic index foods are digested and absorbed more slowly, do not produce surges in blood glucose and blood insulin levels, and therefore are thought to promote weight control.

Adverse effects of low-carbohydrate diets may include constipation, dehydration, electrolyte imbalance, headache, aggravation of renal impairment (increased breakdown of body protein and fat increases the workload of the kidneys), and hyperuricemia leading to gout. In addition, some people experience a worsening of blood lipid levels and one study of adolescents on a very low calorie, low-carbohydrate diet showed increased calcium excretion and decreased bone mineral content. This could lead to later development of osteoporosis.

caloric intake must be considered because it is a major deter-minant of weight loss, gain, or maintenance.

■ Various formula diets or meal-replacement programs are available. The good ones contain high-quality protein, sugar as fructose, and a moderate amount of monounsaturated fat. The usual recommendation is to replace two meals daily for weight loss and one meal for weight maintenance. They can also be used as single meal replacements.

■ Although both calorie-reduced diets and suffi cient exer-cise can lead to weight loss and maintenance, the CCDPC guidelines are based on studies indicating that a combina-tion of the two strategies is more effective than either alone. However, many overweight and obese people may be physi-cally unfi t and unable or unwilling to increase activity. Thus, activity should be started slowly and gradually increased, with the goal of exercise becoming part of the daily routine.

Activities can include chair dancing, fl oor exercises, water aerobics, and swimming. Aerobic exercise increases the metabolic rate during and for approximately 1 hour after activity. Consistent adherence to a reduced-calorie diet and exercise routine is a major factor in achieving weight con-trol and health benefi ts.

■ For any patients following a weight-loss regimen, provide psychological support and positive reinforcement for efforts toward weight management. Programs or support groups involving supervision or regular participation within a social group appear to be more successful over time. Weight Watchers seems more successful than most other commer-cial programs; Overeaters Anonymous and Take Off Pounds Sensibly (TOPS) are large self-help support groups. For more information on commercial programs, see the accom-panying Research Brief.



■ Weight-loss medications are used in the treatment of obe-sity. When drug therapy is indicated, a single drug in the lowest effective dose is recommended. As with most other drugs, low doses decrease risks of adverse drug effects.


Ms. McKay says she needs to lose 140 lb and would like

to accomplish this by her next birthday. How should you

respond?

Management of Obesity in Special PopulationsManaging Obesity in Ethnic PopulationsThe WHO notes that while BMI and waist circumference are useful measures to provide meaningful comparisons within and between populations, caution must be exercised in applying this standard to all ethnic groups. The standards for waist cir-cumference, in particular, were derived from a Caucasian popu-lation and, therefore, their application in other populations, especially in determining the level of risk of incurring disease, is problematic. Asian populations have been shown to differ in the level of risk associated with a specifi c waist circumference. For Chinese and Japanese populations, the WHO report notes that health risks occur at lower body fat levels and smaller waist circumferences than for Caucasians. South Asians (Indians) tend to have a more centralized distribution of body fat but may not be considered obese using BMI standards. It is also suggested that Asians who were born at a low birth weight and are obese as adults tend to develop metabolic syndrome, possibly related to genetics. The normal-weight BMI classi-fi cation is considered between 18.5 and 22.9, with the waist circumference cutoff point of less than 90 cm for men and less than 80 cm for women, with an increased risk of comorbidities if waist circumference was beyond this point.

This report also notes that the ethnic differences prevail in immigrant populations in industrialized countries. This report uses the WHO classifi cation system, but different cutoff points. It is also questionable as to whether appropriate levels of risk can be assigned if First Nations populations are assessed using the standard BMI and waist circumference measures.

Health Canada has produced a Canada’s Food Guide tai-lored for First Nations, Inuit and Metis, providing them with necessary information on healthy living.

Managing Obesity in ChildrenChildren in general need increased amounts of protein, carbo-hydrate, and fat in proportion to their size to support growth and increased physical activity. However, reports of childhood obesity have greatly increased over recent years, and childhood obesity has become a major public health concern. Therefore, the goal of nutrition is to meet needs without promoting obe-sity. When possible, specialists in childhood obesity should design and supervise treatment programs.

Commercial Weight-Loss Programs

Source: Tsai, A. G., & Wadden, T. A. (2005). Systematic review: An evaluation of major commercial weight loss programs in the United States. Annals of Internal Medicine, 142(1), 56–66.Summary: The authors evaluated published studies of medically based weight-loss programs (Health Management Resources and OPTIFAST), non-medical programs (Weight Watchers, Jenny Craig, and L. A. Weight Loss), very low calorie diets, commercial Internet-based programs (eDiets.com), and two non-profi t self-help programs (Overeaters Anonymous and Take Off Pounds Sensibly). The studies included adults in the United States, had >10 participants, and lasted >12 weeks.Few high-quality studies were found; many presented the best-case scenario because they did not account for people who dropped out of the program. Of the programs evalu-ated, Weight Watchers had the strongest studies to support it. No high-quality studies of Jenny Craig or L. A. Weight Loss were found. The studies of the medically based very low calorie diets were of limited quality. Patients who stayed on the program lost substantial weight over 6 mo, but regained about half of the lost weight in 1–2 y; many dropped out. The few studies of Internet-based and self-help programs were of limited quality and found that these approaches produced minimal weight loss.Nursing implications: This information can be used to coun-sel patients who are considering a commercial weight-loss program. Except for Weight Watchers, the programs dem-onstrate little evidence of effectiveness. Costs vary but may be extensive. The Cochrane Central Register of Controlled Trials published a British study (2006) comparing Dr. Atkins’ diet, Slim-Fast plan, and Weight Watchers and Rosemary Conley’s diets and all participants lost weight while on the diets. Clinically useful weight loss can be achieved in all who are motivated to adhere to a diet for a period of time.

Efforts are needed toward both prevention and treatment of childhood obesity. Prevention should focus on identifying at-risk and overweight children and adolescents at an early stage, educating families about the health consequences of being overweight, and encouraging weight-control measures (eg, a more active lifestyle, a low-fat diet, regular meals, avoid-ance of snacking, drinking water instead of calorie-containing beverages, decreasing the time spent watching television and playing computer games, and walking instead of using a car for transportation). These measures are implemented successfully mainly within a family unit and family support is needed to assist the child in weight control and a more healthful lifestyle. In addition, schools should teach children the basic principles of good nutrition and why eating a balanced diet is important to health.

Currently, an amended version of BMI is used for assess-ing pediatric overweight and obesity. This set of reference BMI



Managing Obesity in Patients With Renal ImpairmentIn relation to drugs for obesity, little information is avail-able about their use in patients with renal impairment. With sibutramine, dosage reductions are not recommended with mild to moderate impairment because the drug and its active metabo-lites are eliminated by the liver. However, some inactive metab-olites are also formed and these are excreted renally. The drug is contraindicated in patients with severe renal impairment.

Managing Obesity in Patients With Hepatic ImpairmentIn relation to drugs for obesity, little information is available about their use in patients with hepatic impairment. Because sibutramine is metabolized in the liver, it is contraindicated in patients with severe hepatic impairment.

Managing Obesity in Home CareThe home care nurse may be involved with weight- management issues in almost any home care setting. Because nutrition, exercise, and weight control are so important to health, the home care nurse should take advantage of any opportunity for health promotion in this area. Health promotion may involve assessing the nutritional and fi tness status of all members of the household and providing counselling or other assistance to improve health status. Those who are obviously overweight or who have obesity-related health problems must be approached with diplomacy and tact; they have probably tried repeatedly to lose weight and been told by previous health care providers that they need to lose weight. The home care nurse should be able to provide accurate information about realistic and successful techniques for losing weight and keeping it off; health benefi ts of even modest weight loss; and reasons to avoid “fad” diets, weight-loss herbal and dietary supplements, and programs that promise rapid and easy weight loss with little effort.


How Can You Avoid This Medication Error?Ms. McKay’s prescription is for orlistat (Xenical) three times

a day. She takes the dose with breakfast, lunch, and dinner.

She has a meeting today that runs through lunch and so

she skips lunch but takes her pill on time.

values for children can be used cautiously with an awareness of its limitations. Pediatric clinicians recommend treatment for children and adolescents who are overweight and have com-plications of obesity, and for all children who are obese. Treat-ment of childhood obesity should focus on healthy eating and increasing physical activity. In general, children should not be put on “diets.” For a child who is overweight, the recommended goal is to maintain weight or slow the rate of weight gain so that weight and BMI gradually decline as the child grows in height. If the child has already reached his or her anticipated adult weight, maintenance of that weight and prevention of additional gain should be the long-term treatment goal. If the child already exceeds the optimal adult weight, the goal of treatment should be a slow weight loss of 10 to 12 lb per year until the optimal adult weight is reached. As with adults, increased activity is required for successful weight loss or man-agement in children.

Family involvement and support are vital to children’s weight management. Actually, the goal beyond weight con-trol for a child is to develop healthier eating and exercise habits for long-term health benefi ts for the entire family. Studies indicate that children who eat adequate amounts of fruits, vegetables, and dairy products tend to continue these healthy eating habits. In general, young children who learn to eat a healthy diet are likely to reap the benefi ts throughout their lives. Improved diets and increased activity are unlikely to occur without active participation of parents and other caregivers.

Managing Obesity in Older AdultsOverweight and obesity are common among older adults. Although caloric needs are usually decreased, primarily because of slowed metabolism and decreased physical activity, most people continue usual eating patterns. With the high incidence of atherosclerosis and cardiovascular disease in older adults, it is especially important that fat intake be reduced. The Public Health Agency of Canada promotes healthy active living in an aging society and has information at http://www.phac-aspc.gc.ca/pau-ap/paguide/older/phys_guide.html regarding endur-ance, fl exibility, and strength and balance to maintain health and independence. Anorexiant drugs should be used very cau-tiously, if at all, because older adults often have cardiovascu-lar, renal, or hepatic impairments that increase risks of adverse drug effects.


1. Administer accuratelya. With phentermine

(1) Give single-dose drugs in the early morning. For maximum appetite-suppressant effects during the day,(2) Give multiple-dose preparations 30 min before meals

and the last dose of the day about 6 h before bedtime.For maximum appetite-suppressant effects at mealtime and to avoid interference with sleep from the drug’s stimulating effects on the CNS.

b. With sibutramine, give once daily in the morning.

Drugs for Weight Loss and Maintenance



http://www.phac-aspc.gc.ca/pau-ap/paguide/older/phys_guide.html

http://www.phac-aspc.gc.ca/pau-ap/paguide/older/phys_guide.html



c. With orlistat, give one capsule with each main meal or up to 1 h after a meal, up to three capsules daily. If a meal is missed or contains no fat, the dose should be omitted.

The drug needs to be in the gastrointestinal tract when fat-containing foods are eaten, to prevent fat absorption.

2. Assess for therapeutic effectsa. With phentermine and sibutramine, assess for decreased

caloric intake and weight loss.The recommended rate of weight loss is 0.5–1 kg (1–2 lb) weekly.

b. With orlistat, assess for weight loss and improvements in health status (eg, reduced LDL cholesterol, elevated HDL cholesterol, improved glycemic control, reduced blood pressure).

Most weight loss occurs in the fi rst 6 mo of therapy, but the reduced weight can be maintained as long as orlistat is con-tinued. The metabolic improvements are very benefi cial for people with obesity-related health problems such as diabetes, dyslipidemia, hypertension, and metabolic syndrome.

3. Assess for adverse effectsa. With phentermine and sibutramine, assess for

(1) Nervousness, insomnia, and hyperactivity These effects result from excessive stimulation of the CNS. They are more likely to occur with large doses or too-frequent administration.

(2) Hypertension Anorexiant drugs stimulate the sympathetic nervous system and may cause or aggravate hypertension.

(3) Development of tolerance to appetite-suppressant effects

This usually occurs within 4–6 weeks and is an indication for discontinuing drug administration. Continued administra-tion and/or large doses do not maintain appetite-suppressant effects. Instead, they increase the incidence of adverse effects.

b. With orlistat, assess for abdominal cramping, gas pains, diarrhea, and fatty stools.

These effects commonly occur. They usually improve within a few weeks of continued drug use, but worsen with a high intake of dietary fat, which should be avoided.

4. Assess for drug interactionsa. Drugs that increase effects of phentermine and sibutramine:

(1) Anti-depressants (tricyclic) May increase hypertensive effects(2) Other CNS stimulants Additive stimulant effects(3) Other sympathomimetic drugs (eg, epinephrine) Additive hypertensive and other cardiovascular effects

b. Drugs that decrease effects of phentermine and sibutramine:(1) Anti-hypertensive drugs Decrease blood pressure–raising effects of anorexiants(2) CNS depressants (eg, alcohol) Antagonize or decrease effects

c. Drugs that increase effects of sibutramine:(1) Adrenergics (eg, epinephrine, pseudoephedrine) Additive increases in blood pressure(2) Anti-depressants (tricyclic anti-depressants [TCAs;

eg, amitriptyline], SSRIs [eg, fl uoxetine])TCAs and sibutramine increase levels of norepinephrine and serotonin in the brain; SSRIs increase serotonin levels. Con-current use of these drugs may cause excessive CNS stimula-tion, hypertension, and serotonin syndrome and should be avoided.

(3) Anti-fungals (eg, itraconazole and related azoles) Decrease metabolism and may increase adverse effects and toxicity of sibutramine

(4) Anti-migraine triptans (eg, sumatriptan) Additive serotonin effects(5) Lithium Additive serotonin effect

Drugs for Weight Loss and Maintenance (continued)

Applying Your Knowledge Answers

58-1 Orlistat works by blocking the fat absorbed from

the intestine. This drug will block approximately

30% of the fat ingested in a meal. It is important to

teach that increasing the dose will not increase the

percentage of fat blocked. This drug also blocks the

absorption of fat-soluble vitamins, so you should

advise Ms. McKay to take a multivitamin at a differ-

ent time than the orlistat.



58-2 Strategies should include the practice of a healthy

lifestyle by eating a variety of foods daily and by eat-

ing a diet rich in whole grains, vegetables, and low-

fat dairy products. Limit the intake of saturated fat,

trans fat, cholesterol, added sugars, salt, and alcohol.

Ms. McKay must also include some regular physical

activity.

58-3 The initial goal of weight-loss therapy should be to

reduce body weight by about 10% from baseline and to

lose weight at a rate of 0.5–1 kg/week for the fi rst 6 mo.

Assist Ms. McKay to set a realistic and healthy goal.

58-4 The dose of orlistat should not be taken if the patient

misses a meal. Teach Ms. McKay to omit the dose if a

meal is omitted.

■ Overweight and obesity are major concerns because of their association with numerous health problems, includ-ing diabetes, hypertension, other cardiovascular disorders, and muscles and joint disorders.

■ Ingesting 500 cal more per day than those used in exer-cise and physical activity leads to a weight gain of 1 lb in 1 week; decreasing caloric intake or increasing caloric output of 500 cal/d for 1 week leads to a weight loss of 1 lb.

■ Reducing caloric intake and increasing caloric expenditure are part of any successful weight-loss program.

■ Weight-loss drugs are generally recommended only for people who are seriously overweight or have health prob-lems associated with or aggravated by obesity.

■ Many people lose weight but regain it within a few months if they do not change their lifestyle habits toward eating more healthfully and exercising more.

Key Concepts

Short Answer Exercises

1. Calculate the BMI for yourself, one or more members of your family, or a patient.

2. Assess eating and physical activity habits of yourself, one or more members of your family, or a patient. In general, do these habits promote health or obesity?

3. If you, the family member, or the patient has health prob-lems related to overweight and obesity, list at least three things that can be done to improve health.

4. Debate whether or not it is important that health care providers demonstrate healthful practices in diet, exercise, and weight control to the general public.

5. With an overweight or obese patient who wants to lose weight, what are some nursing interventions to assist and support the patient?

6. List the advantages and disadvantages of drug therapy for weight loss or maintenance.

CRNE-Style Questions

7. Which of the following is a characteristic of low-calorie or reduced-calorie diets?a. They provide about 500–1,000 kcal/d.b. They reduce daily intake by about 1,600 kcal/d.c. They are required for weight loss.d. They focus on high-fat, high-carbohydrate foods.

8. Which of the following statements would indicate a need for drug therapy for weight management?a. A BMI of 22 and a desire to lose 10 lbb. A BMI of 24.5 and physically fi tc. A BMI of 27 or more with weight-related health

problemsd. A BMI of 25–29 and healthy

9. For which of the following disorders would sibutramine (Meridia) be contraindicated?a. Cardiovascular diseaseb. Diabetes mellitusc. Chronic fatigue syndromed. GERD

10. Which of the following statements describes how orlistat (Xenical) aids weight loss?a. Decreasing appetiteb. Increasing satiety and feelings of fullnessc. Increasing metabolismd. Decreasing absorption of dietary fat

11. Which of the following strategies should be taught to a patient to decrease diarrhea when taking orlistat ( Xenical)?a. Avoid large amounts of fatty foods.b. Drink eight glasses of water daily.c. Avoid caffeine-containing beverages.d. Increase physical activity.

Review and Application Exercises



Selected References

Anderson, T., & Fogh, J. (2001). Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients. Journal of Human Nutrition and Dietetics, (14)3, 243–250.

Belanger-Ducharme, F., & Tremblay, A. (2005). Prevalence of obesity in Canada. The International Association for the Study of Obesity, 6, 183–186.

Canadian Pharmacists Association. (2009). Compendium of pharma-ceuticals and specialties. Ottawa, ON: Author.

Dennis, K. E. (2004). Weight management in women. Nursing Clinics of North America, 39, 231–241.

Endocrine and metabolic disorders: Obesity. Accessed at NurseONE, Dr. H. K. Mussallem eLibrary, eTherapeutics, May 27, 2009.

Facts & Comparisons. (Updated monthly). Drug facts and compari-sons. St. Louis, MO: Author.

Health Canada. (2006). It’s your health: Obesity. Retrieved May 21, 2009 from http://www.hc-sc.gc.ca/hl-vsfn-an/food guide-ailment/index-eng.php

Health Canada. (2007). Eating well with Canada’s food guide. Retrieved May 21, 2009 from http://www.hc-sc.gc.ca/fn-an/food guide-ailment/index-eng.php

Health Canada. (2007). Eating well with Canada’s food guide: First Nations, Inuit and Metis. Retrieved May 21, 2009 from http://www.hc-sc.gc.ca/hl-vs/alt_formats/pacrb-dgapar/pdf/iyh-vsv/life-vie/obes-eng.pdf

Institute of Wellbeing. (2009). How are Canadians really doing? Accessed June 28, 2009, www.ciw.ca

Kkuhnlein, H. V., Receveur, O., Soueida, R., et al. (2004). Arctic indigenous peoples experience the nutrition transition with changing dietary patterns and obesity. The American Society for Nutritional Sciences Journal of Nutrition, 134, 1447–1453.

LaQuatra, I. M. (2004). Nutrition for weight management. In L. K. Mahan, & S. Escott-Stump (Eds.), Krause’s food, nutrition and diet therapy (11th ed., pp. 558–593). Philadelphia, PA: W. B. Saunders.

Luo, W., Morrison, H., deGroh, M., et al. (2007). The burden of adult obesity in Canada. Chronic Diseases in Canada, 27(4), 135–143.

Pereira, M., Kartashov, A. I., Ebbeling, C. B., et al. (2005). Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis. Lancet, 365(9453), 36–42.

Pleuss, J. (2005). Alterations in nutritional status. In C. M. Porth (Ed.), Pathophysiology: Concepts of altered health states (7th ed., pp. 217– 238). Philadelphia, PA: Lippincott Williams & Wilkins.

Pronsky, Z. M., & Crowe, J. P. (2004). Food-drug interactions. In L. K. Mahan, & S. Escott-Stump (Eds.), Krause’s food, nutrition and diet therapy (11th ed., pp. 455–474). Philadelphia, PA: W. B. Saunders.

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http://www.hc-sc.gc.ca/hl-vsfn-an/foodguide-ailment/index-eng.php

http://www.hc-sc.gc.ca/hl-vsfn-an/foodguide-ailment/index-eng.php






http://www.phac-aspc.gc.ca/pau-uap/paguide/index.html

http://www.phac-aspc.gc.ca/pau-uap/paguide/index.html

http://www.phac-aspc.gc.ca/ccdpc-cpcmc/hhk-tcs/english/index_eng.php

http://www.phac-aspc.gc.ca/ccdpc-cpcmc/hhk-tcs/english/index_eng.php

http://www.whqlibdoc.who.int/trs/who_trs_894.pdf

http://www.whqlibdoc.who.int/trs/who_trs_894.pdf

http://www.ciw.ca

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