Clinical focus: your residents' daily diet and medicine may not always mix.

"Yes, nurse--tell my doctor I need a refill on ketoprofen, carbamezapine--and six oranges and apples, please."

Before you pick up the phone and seek psychiatric help for your resident, take note: a growing number of healthcare consumers now regard food as a form of medicine. The scientific focus on "functional foods" confirms what pharmacists and dietitians have long known: Diet and drugs can be closely related.

The functional-foods trend merely highlights how naturally occurring components of food can have pharmaceutical actions. Lycopene, for example, can play a role in preventing prostate cancer and omega-3 fatty acids help prevent heart disease. Thus, foods can contribute more to residents' state of health than just nutrients. In a long term care facility, the pharmacist and dietitian can team up to manage the complex and sometimes precarious relationship between food and medicine

Particular foods and nutritional supplements may alter drug absorption or interact with drug metabolism, making a drug more--or less--effective. They may alter timing of drug action. Or, they may interact with drugs to create dangerous health conditions.

On the other side of the coin, medicines can have nutritional side effects, interfering with nutritional care plans. One medicine may interfere with absorption or metabolism of a critical nutrient. Another medicine may create taste changes, appetite changes or gastrointestinal distress, affecting a resident's nutritional well-being and medical resilience.

What's behind it all?

Interactions can occur at many points. For starters, a dietary factor may influence the absorption of a drug. Once a drug is in the body, a dietary factor may influence its metabolism. It may compete with the drug or magnify the drug's action. Furthermore, a dietary factor may alter how a drug is eliminated from the body.

The severity of food-drug interactions varies from one combination to the next. One situation may create interest, without clinical significance. Another can have a profound impact, culminating in medical crisis. Some food-drug interaction management systems rate the risks and set priorities. To prevent clinical surprises, many healthcare teams develop monitoring and educational protocols to address key interactions.

To eat or not to eat

When a physician prescribes a drug with potent food interactions, the bottom-line advice in clinical care often distills into one of two categories: avoid a food (or nutrient) or include a food [see "Avoid a Food, page 18"]

It's worthwhile to note that for some of these interactions, it may be more important to gauge dosage according to diet, rather than avoid foods. The coffee-theophylline is a good example. If a patient is a heavy coffee drinker, some practitioners simply want to know this and moderate the dosage of theophylline. Here, it's simply important that the healthcare team identify the coffee-drinking habit. If the habit changes, the team needs to notice this, too.

Just how serious are some of these interactions? A patient overdosed on the theophylline-coffee combination may experience nervousness, tremor, and insomnia. The felodipine-grapefruit juice connection is one that can have a profound clinical impact, with a hypotensive crisis. Conversely, the MAO inhibitortyramine connection is one that can generate a hypertensive crisis.

In other dietary factors, alcohol can dissolve coatings on time-released drugs, leading to a quick, high dose followed by a drop in drug levels. An action as simple as breaking up a time-released pill to administer it with food can create the same type of problem.

Apart from food itself, use of vitamin and mineral supplements requires attention, too. For example, supplementation with vitamin E (400 IU or more per day) can lengthen clotting time, because Vitamin E itself is an anticoagulant. [See "Include a Food," page 18]

Among the elderly, blood concentrations of many vitamins may run low, according to nutrition research. One possible factor is ongoing drug therapies. Particular medications reduce availability of certain nutrients, or deplete body stores. For example, anti-convulsant medications reduce the body's supplies of vitamin D and folacin. To prevent deficiency, residents may need to drink more milk, eat folacin-rich foods, and/or take vitamin supplements. A drug as innocent as aspirin causes vitamin C loss. To prevent gastrointestinal bleeding, some practitioners advise eating vitamin C rich foods rather than taking oral supplements.

When a resident is following long-term pharmaceutical regimens, it's particularly important to monitor nutritional status. Gastrointestinal side effects, as well as taste changes or appetite changes, are extremely common side effects from medications.

Over time, a patient may lose weight and deplete lean body mass. In turn, a degree of malnutrition becomes a medical risk factor in surgery, immune response and tolerance of a broad range of therapies.

With the upsurge of complementary medicine in the US today, healthcare providers are focusing on the role of herbal supplements in the food drug arena. It's common for healthcare consumers (or well-meaning family members) to practice self-medication with herbs, apart from conventional medical care. By its very nature, complementary or alternative therapy is something a resident or concerned other may not report to the healthcare team [see "Herb Drug Interactions," page 14].

Management approaches

Clearly, managing the risk of food-drug interactions requires interdisciplinary communication and commitment. In a typical protocol, the pharmacist is responsible for contacting the physician when a potential for food-drug interactions arises. Counseling is required [see "Individualized Counseling," below). Dietary instructions pertaining to drug therapy become part of the diet order communicated to a food service department.

Some healthcare organizations rely on interdisciplinary care plans to gather rellevant pieces of the food-drug puzzle together. Computer software, Web sites and PDA (handheld computer) applications exist to provide ready reference [see "A Web Reference," below].

Precautions need to become part of the nursing chart. Nursing staff and other caregivers have ongoing contact with the resident and family, and are most likely to become aware of herbal supplements, gifts of food, or any other factor that may have a bearing.

Among team members, a pharmacist has extensive training in the actions and metabolism of medications, and keeps abreast of new therapies and related research. A dietitian or dietary manager has extensive training in the nutrient components of foods. Nursing staff have extensive interaction with residents and a strong trust relationship. By pooling their expertise, these team members can address the scientific aspect of therapeutic planning and then match food and nutrient lists to individual eating patterns and health habits to assure residents' well-being.

INDIVIDUALIZED COUNSELING

Counseling patients about food-drug interactions has long been a standard of JCAHO, and represents sound clinical management. How counseling responsibilities are assigned varies by institution--often involving a pharmacist, dietitian, and/or nurse--but they must be addressed in care protocols. A basic approach is to identify potential interactions proactively, trigger an education objective, and re-evaluate the list each time medication regimens change.

In addition, a thorough dietary history is essential to determine how a standard interaction list applies to the Individual resident. While reference charts may list several foods high in potassium, for example, most charts do not mention potatoes, tomatoes, broccoli, leafy greens and many other significant sources. The detail is too much to include in a standard "cheat sheet." A dietary history reveals the nutrient-dense food choices of an individual, as well as beverages of choice and other details that weave into customized diet planning. Residents and families also need specific advice about herbal and nutrition supplements, as well as herbal teas. Caregivers can advise residents and significant others to discuss any supplements with the team.

Many institutions use simple instruction sheets and drug information is a feature of many pharmaceutical management software packages. Food-drug interaction guidance is also available in searchable Web databases. Providing printed information in plain English and readable type is important reinforcement. However, a team member needs to sit down with a resident, explain dietary guidance, and apply it to the resident's dietary habits. In addition, it's critical to involve family and significant others, who could unknowingly undermine precautions when bringing in food items or feeding a resident off-site. Occupational and recreational therapists also need to be aware of dietary guidance, too. As follow-up to counseling, caregivers can exercise ongoing vigilance and offer periodic reminders.--S.G.

Herb-Drug Interactions

To find out whether herbal supplements may play a role in resident care, healthcare team members need to be alert and ask questions. Use of herbal supplements should be part of every dietary or medical history completed on admission. Here are some examples of herb-drug concerns.

DRUG                HERBAL INTERACTION       ADVICE

Antidepressant      Gingko--may increase     Identify herbal
medications         blood levels of the      supplements and discuss
                    medicine                 with physician

Antipsychotic       Gingko--may cause        Identify herbal
medications         seizures                 supplements and discuss
                                             with physician

Coumadin/Warfarin   Gingko; coenzyme Q-10;   Identify herbal
                    ginseng--all enhance     supplements and discuss
                    anticoagulant action;    with physician
                    could cause
                    spontaneous bleeding

Insulin or oral     Coenzyme Q-10,           Identify herbal
hypoglycemic        ginseng--can lower       supplements and discuss
drugs               blood sugar, with        with physician
                    potential for
                    hypoglycemic crisis

Avoid a Food

Here are some examples of when a resident might need to avoid a food.

DRUG                   FOOD/NUTRIENT            ADVICE
                       INTERACTION

Coumadin/Warfarin      Food high in vitamin K   Limit foods high in
                       (e.g. dark green leafy   vitamin K while taking
                       vegetables, broccoli,    this drug
                       liver) interfere with
                       drug action

Digoxin                Vitamin D                Avoid vitamin D
                       supplementation--        supplementation while
                       enhances drug action;    taking this drug
                       can cause irregular
                       heartbeat

                       Bran fiber or            Avoid taking fiber with
                       fiber-containing         this medicine
                       laxatives--may
                       decrease drug
                       absorption

Felodipine             Grapefruit juice (not    Avoid grapefruit juice
(anti-hypertensive)    orange juice)--          whithin a few hours
                       increases                before or after taking
                       bioavailability and      this drug
                       can cause drop in
                       blood pressure,
                       flushing, and
                       lightheadedness

Fosamax                Coffee, orange juice     Take without food;
                       or any food taken with   avoid orange juice or
                       the drug can decrease    coffee at medication
                       availability             time

Monoamine oxidase      High-tyramine foods      Avoid high-tyramine
(MAO) inhibitors       (e.g. aged cheese, red   foods while taking this
(e.g. Nardil,          wine) can lead to        drug
Parnate)               hypertensive crisis

Synthroid              Soybeans, turnips,       Avoid making these
(thyroid drug)         cabbage family--         foods a routine part
                       contain natural          of the diet
                       goitrogens; oppose
                       the effect of
                       synthroid

Tetracycline           Milk--reduces            Avoid taking milk and
(antibiotic)           bioavailability by       dairy products with
                       forming chelates         tetracyline, or time
                                                dairy intake several
                                                hours apart from
                                                medication

Theophylline           Coffee--can increase     Avoid coffee while
                       serum levels of the      taking this drug OR
                       drug                     prescribe according to
                                                dietary habit

Triamterene, hydroch   Large quantities of      Moderate high-potassium
lorothiazide           potassium-rich foods     foods in diet
(potassium-sparing     (bananas, oranges,
diuretics)             some salt-substitute
                       products)--can lead
                       to high serum
                       potassium levels and
                       irregular heartbeat

Include a Food

Sometimes presence of a nutrient of dietary factor improves the
availability of a drug to the body. Furthermore, supplemental sources
of nutrients may help protect against nutritional deficiency caused by
a particular medication. Thus in some cases, the alternate advice
holds: Include a food or nutritional supplement in conjunction with a
particular drug. Here are a few examples:

DRUG                   FOOD/NUTRIENT           ADVICE
                       INTERACTION

Oral iron supplement   Orange juice or other   Take the supplement with
                       vitamin C rich food--   a vitamin C rich food
                       vitamin C enhances
                       absorption

Steroid drugs; some    Stomach upset           Take with food
antibiotics;others

FOOD & DRUG: A WEB REFERENCE

HerbMed[R] Database: www.ahpa.org/herbmedDrugFacts. com:www.drugfacts.com

NIH Medline Plus Drug Information: www.nlm.nih.gov/medlineplus/druginformation.html

NIH Office of Dietary Supplements: http://dietarysupplements.info.nih.gov

Sue Grossbauer is a registered dietitian with more than 10 years of experience managing clinical nutrition, food service and employee training. Her company, The Grossbauer Group in Chesterton, Ind., serves professional associations and private corporations in the foodservice and healthcare industries.