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

2. 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)

3. 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)

4. 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)

5. 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)

6. 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)

7. 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)

8. 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)

9. Nutrition & Diet Therapy (7th Edition)

10. 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)

11. 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)

12. 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)

13. 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)

14. 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)

15. 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)

16. 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)

17. 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)

18. Nutrition & Diet Therapy (7th Edition)

19. 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)