FOOD-DRUG INTERACTION
PRESENTED BY:DEEPIKA BARANWALPhD SCHOLAR
DEFINITION Drug-nutrient interaction: the
result of the action between a drug and a nutrient that would not happen with the nutrient or the drug alone.
Food-drug interaction: a broad term that includes drug-nutrient interactions and the effect of a medication on nutritional status.
Food-Drug InteractionFor example, a drug that causes chronic
nausea or mouth pain may result in poor intake and weight loss.
BENEFITS OF MINIMISING DRUG INTERACTION
Medications achieve their intended effects.Patients do not discontinue their drug.The need for additional medication is minimized.Fewer caloric or nutrient supplements are
required.Adverse side effects are avoided.Optimal nutritional status is preserved.Accidents and injuries are avoided.Disease complications are minimized.The cost of health care services is reduced.There is less professional liability.Licensing agency requirements are met.
DRUG EFFECTS ON FOOD INTAKE
Increased appetite (antihistamines, psychotropic drugs and steroids)
Decreased appetite(amphetamines, insulin and alcohol)
Taste changes(chelating agents and diuretics)
Nausea (cardiac glycosides )Bulking effects (methylcellulose and
other dietary fiber products)
DRUG EFFECTS ON NUTRIENT ABSORPTION AND METABOLISM
Increased nutrient absorption (cimetidine and ranitidine)
Decrease nutrient absorption(colchicine, alcohol, laxatives, antibiotic neomycin)
Mineral depletion (diuretics, chelating agents, alcohol, antacids, aspirin)
Vitamin depletion(vitamin antagonists, oral contraceptives)
OUTCOMES OF DRUG AND NUTRIENT INTERACTIONS
BENEFICIAL EFFECTS: Infectious disease controlControl of cancerPrevention of thrombosesTreatment of metabolic diseasePrevention of acute drug toxicity
To be continued :
ADVERSE EFFECTS:Loss of drug efficacy Drug- induced nutritional deficiencies
Toxic reactionsBlocked feeding tubes
Table 1. Drug Induced Nutritional DeficienciesDRUG AFFECTED
NUTRIENTSPOSSIBLE
MECHANISMEFFECT
ANORECTIC DRUGS(amphetamines)
All nutrients Anorexia Decreased food intake
ANTACIDS Phosphates Decreased absorption
Osteomalacia
ANTIEPILECTIC DRUGS (phenytion , phenobarbitone, primidone, valproic acid)
FolateVitamin DVitamin EZinc
SeleniumVitamin K
Decreased absorptionEnzyme induction Excess utilization ?Chelation
Peroxide damage?
Megaloblastic anemiaOsteomalacia Haemolysis Anorexia , celebellar dysfunctionHepatotoxicityHemorrhage
ANTIFOLATE DRUGS(e.g. methotrexate, pyrimethamine, trimethamine, trimethoprim)
Folate Dihydrofolate reductase inhibition
Megaloblastic anemia, cytopenia
BIGUANIDES (phenformin, metformin)
Vitamin B12 Decreased absorption
Megaloblastic anemia
CEPHALOSPORINS (Cefamendole, cefoperazone, latamoxef)
Vitamin K Decreased prothrombin synthesis
Bleeding episodes
To be continued:DRUG AFFECTED
NUTRIENTSPOSSIBLE MECHANISM
EFFECT
CHOLESTYRAMINE Fat , vitamin A,D,K,B12,folate iron
Complex formation bleeding, steatorrhoea
Anaemia ,osteomalacia
COLCHICINE Fat, β-carotene, Na,K, vitamin B12
Mucosal damage Anaemia , lethargy
CORTICOSTEROIDS
Calcium Decreased Ca, vitamin D metabolism
Bone disorders
COUMARIN ANTICOGULANTS
Vitamin K ? Hemorrhage
DIURETICS Zn , Ca, K, Mg Urinary loss depression
Weakness , electrolyte imbalance
FRUSEMIDE Thiamin Urinary loss Cardiac muscle weakness
GLUTETHIMIDE Calcium Enzyme induction, altered calcium metabolism
Weakness, osteopenia
To be continued:
DRUG AFFECTED NUTRIENTS
POSSIBLE MECHANISM
EFFECT
HARMONAL CONTRACEPATIVES STEROIDS
Riboflavin , Folate Enzyme induction, decreased absorption, competition for binding of the enzymes
Metabolic errors, depression
HYDRALAZINE Pyridoxine Complex formation Peripheral neuropathy
ISONIAZED (INH) Pyridoxine Complex formation Peripheral neuropathy, Convulsions, psychatric manifestation
LAXATIVE (MINERAL OILS)
Vitamin D Enzyme inhibition Osteopenia
LEVODOPA Nicotinic acid Competitive inhibition coenzyme and vitamin B6 deficiency
Pellagra
NEOMYCIN Vitamin A,D,E,K, B12,Ca,pyridoxine
Mal-absorption, complex formation, Mucosal damage, binding of bile salts
Osteomalacia, Peripheral neuropathy
To be continued:
DRUG AFFECTED NUTRIENTS
POSSIBLE MECHANISM
EFFECT
PARA – AMINO SALICYCLIC (PAS)
Vitamin B12 decreased absorption
Megaloblastic anaemia
D-PENICILLAMINE Pyridoxine ,Zn, Cu Complex formation Peripheral neuropathy, Anemia
POTASSIUM CHLORIDE
Vitamin B12 decreased ileal Ph Decreased absorption
RIFAMPCIN Vitamin D Enzyme induction Osteomalacia
SALICYLATES Vitamin C, Folate Increased excretion, decreased uptake
Anemia ,infection
NEOMYCIN Vitamin A,D,E,K, B12,Ca,pyridoxine
Mal-absorption, complex formation, Mucosal damage, binding of bile salts
Osteomalacia, Peripheral neuropathy
SULPHASALAZINE Folate Mucosal block Decreased absorption
TETRACYCLINE Iron , vitamin C Chelation Decreased absorption
TYPES:1. Pharmacodynamic Interactions:
which affect the pharmacologic action of the drug.
2. Pharmacokinetic Interaction: which affect the movement of the drug into, around, out of the body.
PHARMACODYNAMICS Pharmaco-dynamics is the study of the
biochemical and physiologic effects of a drug. The mechanism of action, e.g. how a drug
worksOften the drug molecule binds to a receptor,
enzyme, or ion channel, producing a physiological response
PHARMACOKINETICSPharmacokinetics is the study of the time course of a drug in the body involving absorption, distribution, metabolism (biotransformation), and excretion of the drug.
ABSORPTION : Absorption is the process of the movement of the drug
from the site of administration to the blood-stream. This process is dependent on the (1) route of administration, (2) the chemistry of the drug and its ability to cross
biologic membranes, (3.) the rate of gastric emptying & gastrointestinal
movement, and (4.) the quality of product formulation
Food, food components and nutritional supplements can interfere with the absorption process, especially when the drug is administered orally.
AbsorptionSwallowingDisintegration
tablet swellsbreaks up
Dissolutionreactions with acid faster when ionized
Absorptionmost post pyloric in basic environmentrequire non-ionized
state
Food Interactions with AbsorptionMilk products alter pHMetals chelate some medicationsSome foods compete for same absorption
sitesFood speeds GI speed – reduced absorptionDegree of significance is important
DISTRIBUTION:Distribution occurs when the drug leaves
the systemic circulation and moves to various parts of the body
Drugs in the bloodstream are often bound to plasma proteins; only unbound drugs can leave the blood and affect target organs
Low serum albumin can increase availability of drugs and potentiate their effects
Metabolism (biotransformation)Primarily in the liver; cytochrome P-450
enzyme system facilitates drug metabolism; metabolism generally changes fat soluble compounds to water soluble compounds that can be excreted
Foods or dietary supplements that increase or inhibit these enzyme systems can change the rate or extent of drug metabolism
Metabolism – Interaction with foodCytochrome P-450
in GI, liver Grapefruit juice made from frozen concentrate will alter this enzyme
Many drugs for AIDS, HTN
Effects occur 24 hours after ingestion
EXCRETIONDrugs are eliminated from the body as an
unchanged drug or metaboliteRenal excretion the major route of
elimination; affected by renal function and urinary pH
Some drugs eliminated in bile and other body fluids
ExcretionUrine acidity
will change drug excretion
Cranberry juice will alter pH and cause higher dissolution. This occurs with sulfonamides
Lime juice is most acidic
PHARMACOGENOMICSGenetically determined variations that are
revealed solely by the effects of drugsAffect only a subset of peopleExamples include G6PD (glucose-6-
phosphate dehydrogenase) enzyme deficiency, warfarin resistance, and slow inactivation of isoniazid (IHN) or phenelzine
SLOW INACTIVATION OF ISONIAZID OR PHENEIZINE:
Increases the risk of pyridoxine deficiency and peripheral neuropathy.
Slow inactivation of phenelzine, a monoamine oxidase inhibitor (MAOI), increases the risk for hypertensive crisis if foods high in tyramine are consumed.
G6PD (GLUCOSE-6-PHOSPHATE DEHYDROGENASE) ENZYME DEFICIENCYIt can lead to : Neonatal jaundice, hemolytic
anemia or acute hemolysis.It is also called favism.Drugs included: aspirin, sulfonamides and
antimalerial drugs caused hemolysis and acute anemia.
Food –drug interactions in G6PD deficiency :Ingestion of fava beansVitamin CVitamin K
WarfarinAnticoagulant used to reduce strokesInactivated by Vitamin K - broccoliEnteral nutrition products contain Vitamin
K.Warfarin activity drops when nutrition
givenStudy shows warfarin binds to protein at
pH 8