Nutrient drug interaction
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Nutrient drug interaction






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Nutrient drug interaction Nutrient drug interaction Presentation Transcript

  • DEFINITION Drug-nutrient interaction: the result ofthe action between a drug and a nutrientthat would not happen with the nutrient orthe drug alone. Food-drug interaction: a broad term thatincludes drug-nutrient interactions and theeffect of a medication on nutritional status.
  • Food-Drug Interaction For example, a drug that causes chronic nausea ormouth pain may result in poor intake and weightloss.
  • BENEFITS OF MINIMISING DRUGINTERACTION 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, insulinand alcohol)Taste changes(chelating agents anddiuretics)Nausea (cardiac glycosides )Bulking effects (methylcellulose and otherdietary fiber products)
  • DRUG EFFECTS ON NUTRIENTABSORPTION AND METABOLISM Increased nutrient absorption (cimetidineand ranitidine) Decrease nutrientabsorption(colchicine, alcohol, laxatives, antibiotic neomycin) Mineral depletion (diuretics, chelatingagents, alcohol, antacids, aspirin) Vitamin depletion(vitamin antagonists, oralcontraceptives)
  • OUTCOMES OF DRUG AND NUTRIENTINTERACTIONS BENEFICIAL EFFECTS:Infectious disease controlControl of cancerPrevention of thrombosesTreatment of metabolic diseasePrevention of acute drug toxicity
  • To be continued :ADVERSE EFFECTS:Loss of drug efficacyDrug- induced nutritional deficienciesToxic reactionsBlocked feeding tubes
  • Table 1. Drug Induced Nutritional DeficienciesDRUG AFFECTEDNUTRIENTSPOSSIBLEMECHANISMEFFECTANORECTIC DRUGS(amphetamines)All nutrients Anorexia Decreased food intakeANTACIDS Phosphates Decreased absorption OsteomalaciaANTIEPILECTICDRUGS(phenytion ,phenobarbitone,primidone,valproic acid)FolateVitamin DVitamin EZincSeleniumVitamin KDecreased absorptionEnzyme inductionExcess utilization ?ChelationPeroxide damage?Megaloblastic anemiaOsteomalaciaHaemolysisAnorexia , celebellardysfunctionHepatotoxicityHemorrhageANTIFOLATE DRUGS(e.g. methotrexate,pyrimethamine,trimethamine,trimethoprim)Folate Dihydrofolate reductaseinhibitionMegaloblastic anemia,cytopeniaBIGUANIDES(phenformin,metformin)Vitamin B12 Decreased absorption Megaloblastic anemia
  • To be continued:DRUG AFFECTEDNUTRIENTSPOSSIBLEMECHANISMEFFECTCHOLESTYRAMINE Fat , vitaminA,D,K,B12,folate ironComplex formationbleeding, steatorrhoeaAnaemia ,osteomalaciaCOLCHICINE Fat, β-carotene, Na,K,vitamin B12Mucosal damage Anaemia , lethargyCORTICOSTEROIDS Calcium Decreased Ca, vitaminD metabolismBone disordersCOUMARINANTICOGULANTSVitamin K ? HemorrhageDIURETICS Zn , Ca, K, Mg Urinary loss depression Weakness , electrolyteimbalanceFRUSEMIDE Thiamin Urinary loss Cardiac muscleweaknessGLUTETHIMIDE Calcium Enzyme induction,altered calciummetabolismWeakness, osteopenia
  • To be continued:DRUG AFFECTEDNUTRIENTSPOSSIBLEMECHANISMEFFECTHARMONALCONTRACEPATIVESSTEROIDSRiboflavin , Folate Enzyme induction,decreased absorption,competition for bindingof the enzymesMetabolic errors,depressionHYDRALAZINE Pyridoxine Complex formation Peripheral neuropathyISONIAZED (INH) Pyridoxine Complex formation Peripheral neuropathy,Convulsions, psychatricmanifestationLAXATIVE (MINERALOILS)Vitamin D Enzyme inhibition OsteopeniaLEVODOPA Nicotinic acid Competitive inhibitioncoenzyme and vitaminB6 deficiencyPellagraNEOMYCIN Vitamin A,D,E,K,B12,Ca,pyridoxineMal-absorption,complex formation,Mucosal damage,binding of bile saltsOsteomalacia,Peripheral neuropathy
  • To be continued:DRUG AFFECTEDNUTRIENTSPOSSIBLEMECHANISMEFFECTPARA – AMINOSALICYCLIC (PAS)Vitamin B12 decreased absorption Megaloblastic anaemiaD-PENICILLAMINE Pyridoxine ,Zn, Cu Complex formation Peripheral neuropathy,AnemiaPOTASSIUMCHLORIDEVitamin B12 decreased ileal Ph Decreased absorptionRIFAMPCIN Vitamin D Enzyme induction OsteomalaciaSALICYLATES Vitamin C, Folate Increased excretion,decreased uptakeAnemia ,infectionNEOMYCIN Vitamin A,D,E,K,B12,Ca,pyridoxineMal-absorption,complex formation,Mucosal damage,binding of bile saltsOsteomalacia,Peripheral neuropathySULPHASALAZINE Folate Mucosal block Decreased absorptionTETRACYCLINE Iron , vitamin C Chelation Decreased absorption
  • TYPES:1. Pharmacodynamic Interactions: whichaffect the pharmacologic action of thedrug.1. Pharmacokinetic Interaction: whichaffect the movement of the druginto, around, out of the body.
  • PHARMACODYNAMICSPharmaco-dynamics is the study of the biochemicaland physiologic effects of a drug. The mechanism of action, e.g. how a drug works Often the drug molecule binds to a receptor, enzyme,or ion channel, producing a physiological response
  • PHARMACOKINETICSPharmacokinetics is the study of thetime course of a drug in the bodyinvolving absorption, distribution,metabolism (biotransformation), andexcretion of the drug.
  • ABSORPTION : Absorption is the process of the movement of the drug from the siteof 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 biologicmembranes, (3.) the rate of gastric emptying & gastrointestinal movement, and (4.) the quality of product formulation Food, food components and nutritional supplements can interferewith the absorption process, especially when the drug isadministered orally.
  • Absorption Swallowing Disintegration tablet swells breaks up Dissolution reactions with acid faster when ionized Absorption most post pyloric in basic environment require non-ionized state
  • Food Interactions with Absorption Milk products alter pH Metals chelate some medications Some foods compete for same absorption sites Food speeds GI speed – reduced absorption Degree of significance is important
  • DISTRIBUTION:Distribution occurs when the drug leaves thesystemic circulation and moves to various parts ofthe body Drugs in the bloodstream are often bound toplasma proteins; only unbound drugs can leave theblood and affect target organs Low serum albumin can increase availability ofdrugs and potentiate their effects
  • Metabolism (biotransformation) Primarily in the liver; cytochrome P-450 enzymesystem facilitates drug metabolism; metabolismgenerally changes fat soluble compounds to watersoluble compounds that can be excreted Foods or dietary supplements that increase or inhibitthese enzyme systems can change the rate or extent ofdrug metabolism
  • Metabolism – Interaction with food Cytochrome P-450 inGI, liver Grapefruit juicemade from frozenconcentrate will alterthis enzyme Many drugs for AIDS,HTN Effects occur 24 hoursafter ingestion
  • EXCRETION Drugs are eliminated from the body as anunchanged drug or metabolite Renal excretion the major route of elimination;affected by renal function and urinary pH Some drugs eliminated in bile and other bodyfluids
  • Excretion Urine acidity willchange drugexcretion Cranberry juicewill alter pH andcause higherdissolution. Thisoccurs withsulfonamides Lime juice is mostacidic
  • PHARMACOGENOMICS Genetically determined variations that arerevealed solely by the effects of drugs Affect only a subset of people Examples include G6PD (glucose-6-phosphatedehydrogenase) enzyme deficiency, warfarinresistance, and slow inactivation of isoniazid(IHN) or phenelzine
  • SLOW INACTIVATION OF ISONIAZID OR PHENEIZINE: Increases the risk of pyridoxinedeficiency and peripheralneuropathy. Slow inactivation ofphenelzine, a monoamineoxidase inhibitor (MAOI),increases the risk forhypertensive crisis if foodshigh in tyramine areconsumed.
  • G6PD (GLUCOSE-6-PHOSPHATEDEHYDROGENASE) ENZYME DEFICIENCY It can lead to : Neonatal jaundice, hemolytic anemia oracute hemolysis. It is also called favism. Drugs included: aspirin, sulfonamides andantimalerial drugs caused hemolysis and acuteanemia. Food –drug interactions in G6PD deficiency :Ingestion of fava beansVitamin CVitamin K
  • Warfarin Anticoagulant used to reduce strokes Inactivated by Vitamin K - broccoli Enteral nutrition products contain Vitamin K. Warfarin activity drops when nutrition given Study shows warfarin binds to protein at pH 8