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Part II Nutrition Assessment, Consequences, and Implications

usefulness of the Beers Criteria is somewhat controver- sial among prescribers (10).

Care must be taken to evaluate intake of interact- ing nutrients (in the oral diet, supplements, or tube feedings) when specific drugs are used. Examples are vitamin K with warfarin (Coumadin); calcium and vitamin D with alendronate (Fosamax); and potas- sium, sodium, and magnesium with loop diuretics such as furosemide (Lasix). Those diagnosed with Parkinson’s disease may be concerned with the amount and timing of protein intake because of inter- action with levodopa (Sinemet, Dopar) (11). The interdisciplinary team (IDT), which includes the phy- sician, pharmacist, nurse, rehabilitation therapist, social services, registered dietitian nutritionist (RDN), and other specialists, must work together to plan and coordinate the medication regimen along with diet and nutritional supplements to preserve optimal nutrition status and minimize food-drug interactions. Many of the side effects from drug therapy may not be directly due to the drug itself but rather are the result of nutri- tion deficiencies that are caused by the drug taken over time (12).

DRUG-NUTRIENT ADVERSE SIDE

EFFECTS Technically, any drug effect other than the intended therapeutic effect can be classified as an adverse reac- tion. Mild but predictable adverse reactions are known as adverse side effects. Drowsiness is an example of a relatively benign adverse side effect. An adverse side effect is often tolerated because the ben- efits of a drug outweigh the risk of the adverse side effect. However, an adverse side effect may prove to be unacceptably harmful and necessitate discontinua- tion of a drug. Adverse effects may diminish or disap- pear with continued drug administration because of tolerance.

Adverse drug side effects that can influence the nutritional status of older adults include:

●● ●● ●● ●● ●● ●● ●● ●● ●● ●● ●●

appetite changes weight changes edema

altered taste thirst

dry mouth

increased risk of dental problems GI distress

nausea/vomiting diarrhea

constipation ●● ●●

blood pressure changes drowsiness

In addition to being aware of potential drug side

effects, RDNs need to understand a medication’s influ- ence on electrolytes, its consequences for nutritionally significant laboratory tests, and whether it should be taken with food, alcohol, or caffeine. Even if a drug is identified in clinical trials as having a potential for an adverse side effect, an indi- vidual taking the drug may or may not experience the side effect. Many factors such as medical status, nutri- tional status, polypharmacy, concurrent use of over- the-counter medications and herbal or nutritional supplements, and nondrug factors may contribute to or cause adverse side effects.

DIFFERENCES BETWEEN DRUG-NUTRIENT AND

FOOD-DRUG INTERACTIONS “The terms drug-nutrient interaction and food-drug interaction are often used interchangeably. In actuality, drug-nutrient interactions are some of the many possible food-drug interactions. Drug-nutrient interactions include specific changes to the pharmacokinetics of a drug caused by a nutrient or nutrients or changes to the kinetics of a nutrient caused by a drug” (13). Pharma- cokinetics includes the absorption, distribution, conver- sion to active form, and elimination of medication. Food-drug interaction is a broader term that also includes the effects of a medication on nutritional status. Nutritional status may be impacted by the side effects of a medication, which could include an effect on appetite or the ability to eat.

FOOD-DRUG INTERACTIONS Older adults tend to require more medication therapy than do other age groups. Thirty percent of hospital admissions for older adults can be associated with problems with medication, according to the Beers Criteria (9). This can include food-drug interactions. Such interactions can change the effects of drugs, including the therapeutic effects or adverse drug effects and, alternately, may in some cases alter the nutrition status of an individual. Use of herbal or other supple- ments, genetic makeup, or the nutritional status of the older adult can affect the efficacy of a drug or increase its toxicity (10).

In addition to a drug’s potential adverse side effects and its influence on the nutritional status of older adults, the alert RDN is aware of the influence that food and nutrients have on the pharmacokinetics of a drug. Individuals taking vitamins, minerals, and other food