Ppt chapter 28

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 28

Drugs Affecting Lipid Levels

Chapter 28

Drugs Affecting Lipid Levels


QuestionQuestion

• What is the optimal low-density lipoprotein (LDL) level?

– A. 200 mg/dL

– B. 160 mg/dL

– C. 130 mg/dL

– D. 100 mg/dL


AnswerAnswer

• D. 100 mg/dL

• Rationale: 100 mg/dL is the optimal LDL level according to NCEP. Some newer data are suggesting that the LDL should be even lower than that in patients with risk factors for myocardial infarctions and strokes.


Physiology Physiology

• Serum lipids are fats found in the bloodstream.

• These lipids include cholesterol, cholesterol esters (compounds), phospholipids, and triglycerides.

• They are transported in the blood as part of large molecules called lipoproteins.

• Cholesterol is a soft, waxy substance found among the lipids in the bloodstream and in all of the body’s cells.


Physiology (cont.)Physiology (cont.)

• The body, mostly in the liver, produces essentially all of the cholesterol needed for normal functioning—about 1,000 mg a day.

• Cholesterol plays a role in forming cell membranes, some hormones, and other needed tissues.

• LDL is the major cholesterol carrier in the blood.


Pathophysiology Pathophysiology

• Hyperlipidemia is an elevation of blood lipid levels.

• Hyperlipidemia is considered a risk factor for the following disorders: atherosclerosis, coronary artery disease, and thromboses.

• When the amount of cholesterol within cells builds up, the number of these receptors on cell surfaces is reduced, preventing all of the lipids from entering the cells.


Pathophysiology (cont.)Pathophysiology (cont.)

• Patients with narrowed arteries from atherosclerotic cardiovascular disease are more likely to have hypertension.

• Ideal cholesterol levels:

– Total cholesterol: less than 200 mg/dL

– LDL: 100 mg/dL

– HDL: 40 to 59 mg/dL


Lifestyle and Reduction of Low-Density Lipoprotein Levels Lifestyle and Reduction of Low-Density Lipoprotein Levels

• The NCEP ATP III recommends a multipronged approach in reducing LDL levels.

• They title this approach therapeutic lifestyle changes.

• These lifestyle changes include:

– Diet

– Weight loss

– Increased physical activity


AntihyperlipidemicsAntihyperlipidemics


Statins Statins

• Statins lower blood cholesterol levels and thus decrease the uptake of modified lipoproteins by vascular cells.

• Statin therapy can lower LDL cholesterol by 20% to 55% when given at their maximum recommended dose.

• Statins also raise HDL levels between 5% and 15% and lower triglycerides between 7% and 33%.

• In addition, evidence exists that statins work in other ways beside lowering cholesterol levels to decrease the occurrence of cardiovascular events.

• Prototype drug: lovastatin (Mevacor)


Lovastatin: Core Drug Knowledge Lovastatin: Core Drug Knowledge

• Pharmacotherapeutics

– Used for primary hypercholesterolemia and combined hyperlipidemia

• Pharmacokinetics

– High first-pass effect. Highly protein bound. Excreted primarily through the GI tract

• Pharmacodynamics

– Competitively inhibits HMG-CoA reductase, which is the enzyme that catalyzes the early rate-limiting step in cholesterol biosynthesis


Lovastatin: Core Drug Knowledge (cont.)Lovastatin: Core Drug Knowledge (cont.)

• Contraindications and precautions

– Active liver disease and pregnancy

• Adverse effects

– Muscle and joint aches, weakness, cramps, muscle damage, liver damage, and rhabdomyolysis

• Drug interactions

– Itraconazole, erythromycin, and grapefruit juice


Lovastatin: Core Patient Variables Lovastatin: Core Patient Variables

• Health status

– Assess cholesterol levels and past medical history.

• Life span and gender

– Pregnancy category X; assess age of the patient

• Lifestyle, diet, and habits

– Treat elevated cholesterol with diet and exercise first.

• Environment

– Assess environment where drug will be given.

• Culture and inherited traits

– Explore cultural dietary practices.


Lovastatin: Nursing Diagnoses and Outcomes Lovastatin: Nursing Diagnoses and Outcomes

• Risk for Injury related to elevated blood lipid levels

– Desired outcome: The patient’s blood lipid levels will be controlled without the patient’s sustaining an injury.

• Risk for Injury to skeletal muscles related to adverse effects of drug therapy

– Desired outcome: The patient will not incur serious skeletal muscle injury while on drug therapy.


Lovastatin: Nursing Diagnoses and Outcomes (cont.)Lovastatin: Nursing Diagnoses and Outcomes (cont.)

• Risk for Injury to liver function related to adverse effects of drug therapy

– Desired outcome: The patient will not incur serious liver injury while on drug therapy.

• Risk for Altered Nutrition: Less than Body Requirements related to adverse effects of drug therapy

– Desired outcome: The patient will not have GI adverse effects serious enough to alter meeting the body’s nutritional needs.


Lovastatin: Planning and InterventionsLovastatin: Planning and Interventions

• Maximizing therapeutic effects

– Most effective when administered in the evening

– Immediate-release administered after evening meal

– Extended-release administered at bedtime

• Minimizing adverse effects

– Liver function test (AST and ALT) results should be monitored before starting therapy.

– Evaluate the patient carefully for muscle soreness, tenderness, or pain and CK levels.


Lovastatin: Teaching, Assessment, and EvaluationsLovastatin: Teaching, Assessment, and Evaluations

• Patient and family education

– Stress the importance of following a low-cholesterol and low-saturated-fat diet.

– Instruct patients to report any unexplained muscle pain, tenderness, or weakness.

– Photosensitivity may occur.

• Ongoing assessment and evaluation

– The patient should have liver function tests and CK measurement performed periodically throughout drug therapy.


QuestionQuestion

• Lovastatin is metabolized by which of the following process/system?

– A. CYP3A4

– B. 2D6

– C. C121

– D. No process is needed for metabolism.


AnswerAnswer

• A. CYP3A4

• Rationale: Lovastatin is metabolism by CYP3A4.


Drugs Closely Related to LovastatinDrugs Closely Related to Lovastatin

• Atorvastatin (Lipitor), fluvastatin (Lescol), pravastatin (Pravachol), rosuvastatin (Crestor), and simvastatin (Zocor)

• All work similarly to lower LDL cholesterol and have similar adverse effects.

• Pravastatin differs from the prototype lovastatin because it is not metabolized via the P-450 system and thus does not produce the drug interactions of lovastatin.

• Fluvastatin is primarily metabolized via a different isoenzyme pathway.


Statin TherapyStatin Therapy


Drugs Significantly Different from Lovastatin: Fibric Acid DerivativesDrugs Significantly Different from Lovastatin: Fibric Acid Derivatives

• These drugs lower triglyceride levels and increase HDL cholesterol.

• These drugs can reduce triglyceride levels between 35% and 53%.

• Effects on LDL cholesterol may be either to lower it between 6% and 20% or to raise it slightly.

• Although in certain patients these drugs may be used alone, most frequently they are used in combination with statins.


Drugs Significantly Different from Lovastatin: Fibric Acid Derivatives (cont.)Drugs Significantly Different from Lovastatin: Fibric Acid Derivatives (cont.)

• The combined used of a fibrate and a moderate-dose statin carries a somewhat increased risk of myopathy.

• Contraindications include hepatic or severe renal dysfunction, including primary biliary cirrhosis, preexisting gallbladder disease, or hypersensitivity.

• Serious adverse effects include abnormal liver function tests, rhabdomyolysis, and hyperglycemia.


Drugs Significantly Different from Lovastatin: Cholesterol Absorption Inhibitors

Drugs Significantly Different from Lovastatin: Cholesterol Absorption Inhibitors • Ezetimibe (Zetia) is an antilipid drug that is used to treat

hypercholesterolemia.

• Its pediatric use is restricted to children older than 10 years of age with familial homozygous hypercholesterolemia.

• It is given orally once daily either as monotherapy or in combination therapy with a statin.

• It localizes and appears to act at the brush border of the small intestine, where it inhibits the absorption of cholesterol.

• Ezetimibe decreases LDL about 17% but has no effect on HDL or triglycerides.


Drugs Significantly Different from Lovastatin: Nicotinic AcidDrugs Significantly Different from Lovastatin: Nicotinic Acid

• Nicotinic acid (niacin or vitamin B3) is used to treat hyperlipidemia.

• Nicotinic acid reduces levels of triglycerides and LDL cholesterol levels and raises levels of HDL cholesterol.

• Triglycerides and VLDL levels are reduced by 25% to 30% in 1 to 4 days. LDL level reductions may be seen in 5 to 7 days, with the maximal effect seen in 3 to 5 weeks.


Drugs Significantly Different from Lovastatin: Nicotinic Acid (cont.)Drugs Significantly Different from Lovastatin: Nicotinic Acid (cont.)

• Contraindications to its use include hepatic dysfunction, active peptic ulcer, severe hypotension, and hemorrhaging.

• The newer sustained-release forms of nicotinic acid have fewer adverse effects.

• These larger doses produce peripheral vasodilation, mostly in the cutaneous vessels of the face, neck, and chest.


Drugs Significantly Different from Lovastatin: Bile Acid Sequestrants Drugs Significantly Different from Lovastatin: Bile Acid Sequestrants

• The bile acid sequestrants cholestyramine (LoCholest, Questran, Prevalite) and colestipol (Colestid) are used to reduce elevated serum cholesterol levels in patients with primary hypercholesterolemia who have not responded to other drug therapy.

• Bile acid sequestrants are not absorbed orally but work in the GI tract.

• The reduction in LDLs is apparent in 4 to 7 days and ranges between 15% and 30%.

• Bile acid sequestrants promote the oxidation of cholesterol to bile acids.

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