Medications, Herbal Supplements, & Diet-Drug Interactions Chapter 15 Nutrition & Diet Therapy (7th Edition)

Medications in Disease Treatment Medications used to prevent & treat health problems Herbal supplements often used as alternative therapy Any ingested chemical can affect metabolism & produce adverse effects Drug-drug interactions Diet-drug interactions Nutrition & Diet Therapy (7th Edition)

Medications in Disease Treatment (con’t) Prescription drugs Use requires physician evaluation of patient’s condition Given to treat serious conditions May cause severe side effects Over-the-counter drugs Can be used safely & effectively without medical supervision Used for less serious conditions May cause adverse effects, especially if used inappropriately Generic drugs Chemically identical & act the same as original drug Cost significantly less than brand-name counterparts Although OTC drugs are considered safe enough for self-medication, they can cause adverse effects when used inappropriately Nutrition & Diet Therapy (7th Edition)

Medications in Disease Treatment (con’t) Risks from medications Any drug carries some risk of adverse reaction Drug considered “safe” when benefits of use outweigh potential risks Risks greater when incorrectly used (prescribed &/or administered) Potential Risks Side effects Drug-drug interactions Diet-drug interactions Medication errors-see Table 15-1, Inappropriate Abbrev., p.440 Nutrition & Diet Therapy (7th Edition)

Medications in Disease Treatment (con’t) Elderly people using multiple meds are especially susceptible to adverse effects Patients at greatest risk Pregnant & lactating women Children Older adults Individuals with medical conditions that were not studied during drug development Health professionals should discuss risks & benefits of medications; alert patients to potential dangers & solutions Nutrition & Diet Therapy (7th Edition)

Medications in Disease Treatment (con’t) Reducing risk Patient counseling & education Discussion of lifestyle or dietary practices as alternatives to drug therapy Assessment of all medications, including prescription, OTC & dietary supplements Monitoring side effects Assessment of patient understanding of medication use, interactions & drug safety Nutrition & Diet Therapy (7th Edition)

Herbal Supplements Widely used by consumers to improve general health & prevent or treat specific illnesses Do not require FDA approval before marketing FDA must show that herbal supplement is unsafe before it can be removed from marketplace (ex. ephedrine) Manufacturers & distributors are responsible for determining safety Not required to provide evidence FDA notification of illness or injury related to use of product is not required Nutrition & Diet Therapy (7th Edition)

Effectiveness & Safety Benefits of use of herbal products is unclear Many herbal “remedies” of dubious effectiveness Efficacy: limited number of studies to support traditional uses & benefits Consistency in ingredients: variations occur in composition of herb & in preparation; may contain harmful components Safety issues: products often considered “natural,” therefore safe; may have toxic effects, however—some serious, even dangerous Interactions: may potentiate or interfere with actions of other herbs or drugs Contamination: some products found to contain lead & other toxic metals; other contaminants include molds, bacteria, pesticides Adulteration of imported products, including addition of synthetic drugs not identified on labels Nutrition & Diet Therapy (7th Edition)

Nutrition & Diet Therapy (7th Edition)

Use of Herbal Products in Illness Self-medication & herbal remedies may delay appropriate treatment & allow progression of illness Herbal products may interact with other medications—lack of research makes assessment of interactions difficult Herbal products are not reliable treatment for medical conditions Nutrition & Diet Therapy (7th Edition)

Diet-Drug Interactions Diet-drug interactions fall into the following categories: Medications can alter food intake by suppressing appetite or causing complications that interfere with food intake Medications can alter absorption, metabolism & excretion of nutrients Nutrients & other food components can alter absorption, metabolism & excretion of medications Some interactions between food components & medications can be toxic Nutrition & Diet Therapy (7th Edition)

Diet-Drug Interactions (con’t) Drug Effects on Food Intake Reduce food intake through… Nausea & vomiting Alteration of taste sensations Suppression of appetite Drying mouth, inflammation or lesions in mouth or GI tract Side effects, including abdominal discomfort, constipation, diarrhea Drowsiness Other symptoms-p. 447 Table 15-5 Ex: sedatives Nutrition & Diet Therapy (7th Edition)

Diet-Drug Interactions (con’t) To prevent diet-drug interactions, find out about all the drugs & supplements a patient takes Drug effects on nutrient absorption Damage of intestinal mucosa: most widespread cause of problems with nutrient absorption; especially antineoplastic & antiretroviral medications Drug-nutrient binding: binding of nutrients & drugs in GI tract, preventing absorption (ex. Ciprofloxacin) Altered stomach acidity: resulting in impaired absorption of vitamin B12, folate & iron (ex. Antacids) Direct inhibition: drugs that impede nutrient absorption by interfering with intestinal metabolism or transport Nutrition & Diet Therapy (7th Edition)

Diet-Drug Interactions (con’t) Dietary effects on drug absorption Stomach emptying rate: taking medications on empty stomach tends to increase absorption rate; taking medications on full stomach may delay its absorption rate (ex. Aspirin) Stomach acidity: absorption rates affected by acid or alkaline medium Interactions with food components: may bind with drugs & inhibit absorption Drug effects on nutrient metabolism Enhancement or inhibition of activities of enzymes needed for nutrient metabolism (ex. Methotrexate with folate) Alteration in absorption & metabolism Nutrition & Diet Therapy (7th Edition)

Diet-Drug Interactions (con’t) Dietary effects on drug metabolism Alteration in activities of enzymes that metabolize drugs Increased blood concentration of drug (stronger physiological effects)-ex. Grapefruit and statins Decreased effectiveness of drug (ex. Warfarin and vitK) Counteraction of drug effects in other ways Drug effects on nutrient excretion Alteration in mineral reabsorption Increased excretion of vitamins & minerals (ex. INH and vit. B6) Nutrition & Diet Therapy (7th Edition)

Diet-Drug Interactions (con’t) Dietary effects on drug excretion Alterations in excretion causing toxicity or reduced effectiveness of the drug Increased or decreased reabsorption (ex. Li and Na) Alterations in drug actions Diet-drug interactions & toxicity Interactions can result in toxicity or exacerbate drug side effects (ex. MAOI and tyramine) Health professions must understand mechanism of action of drugs & diet-drug interactions for identification &/or prevention Nutrition & Diet Therapy (7th Edition)

Nutrition in Practice—Complementary & Alternative Therapies Use of complementary & alternative medicine (CAM) most prevalent among individuals with chronic, debilitating diseases Reasons for popularity include growing interest in “self-help” measures & non-invasive nature of the therapies National Center for Complementary & Alternative Medicine established in 1998 One of institutes making up the National Institutes of Health Mission is to investigate CAM through scientific studies and to provide authoritative information to consumers & health care professionals Health professionals need to be familiar with CAM so they can communicate with patients & offer advice Nutrition & Diet Therapy (7th Edition)

Nutrition & Diet Therapy (7th Edition)

Nutrition in Practice—Complementary & Alternative Therapies Role of health practioner Identify & communicate with patients who are using CAM Educate patients regarding hazards of postponing or discontinuing conventional therapy Educate patients regarding possible interactions & adverse reactions Identify ways to integrate CAM & conventional treatment Practitioner needs to regularly update knowledge of alternative therapies in order to knowledgably discuss options with patients Nutrition & Diet Therapy (7th Edition)