Transcript Medications, Herbal Supplements & Diet

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 brandname counterparts
Nutrition & Diet Therapy (7th Edition)
• Although OTC drugs are
considered safe enough for
self-medication, they can
cause adverse effects when
used inappropriately
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)
Nutrition & Diet Therapy (7th Edition)
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Potential Risks
Side effects
Drug-drug interactions
Diet-drug interactions
Medication errors-see
Table 15-1, Inappropriate
Abbrev., p.440
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)
Nutrition & Diet Therapy (7th Edition)
• 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
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…
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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
Drug effects on nutrient absorption
the drugs & supplements a
• Damage of intestinal mucosa:
patient takes
most widespread cause of problems
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•
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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 “selfhelp” 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)