Study Examines Interactions Between Drugs and Dietary Supplements
Researchers at the University of Pittsburgh in Pennsylvania have found that patients who take prescription drugs along with herbal supplements have few adverse reactions. Results of their study were published in the March 22 issue of the Archives of Internal Medicine.
The Pittsburgh researchers had sought to explore both the incidence and severity of potential interactions between prescription medications and dietary supplements and found that most of the interactions—approximately 94% of the patient population studied—were not serious, based on limited available evidence.
Although the study gives encouraging news to patients taking prescription medications along with dietary supplements, "limited information on drug-dietary interactions exists, and health care providers should continue to inquire about dietary supplement use and consider the potential for interactions, regardless of their severity," says Lauren E. Trilli, PharmD, BCPS, assistant professor, department of pharmacy and therapeutics, University of Pittsburgh School of Pharmacy and a clinical pharmacy specialist at the Pittsburgh VA Healthcare System.
The researchers surveyed 458 outpatients visiting general medicine clinics at two Veterans Affairs (VA) Medical Centers located in Los Angeles and Pittsburgh. Because herbal supplements are used more frequently in the western half of the United States, the researchers sought to sample one VA health care system on the West Coast and compare results with a VA health care system on the East Coast.
The survey participants were asked whether they have ever taken in the past, or were currently taking the following dietary supplements: chondroitin, coenzyme Q10, DHEA, echinacea, garlic, Gingko biloba, ginseng, glucosamine, melatonin, saw palmetto, St. John’s wort, vitamin, or other.
The researchers cross-referenced self-reported use of dietary supplements with prescription of medications by VA health care providers, and potential interactions were identified from various sources and medical searches. All 458 patients surveyed were prescribed prescription medications, with an average of seven oral prescriptions per patient in Pittsburgh and six oral prescriptions per patient in Los Angeles. Of these patients, 197 or 43% were taking at least one dietary supplement, and the average consumption was three dietary supplements per day.
Pharmacies and grocery stores were the most common places of purchase of dietary supplements. A monthly expenditure of less than $25 on supplements was reported by 83% of the patients surveyed from Pittsburgh and 72% of the patients surveyed from Los Angeles. The most common reported sources of information regarding dietary supplements were friends or relatives and books or magazines.
Among the patients taking supplements, 48% of the Pittsburgh patients and 43% of the Los Angeles patients had potential drug-dietary supplement interactions of any significance. Most patients had one or two possible drug-dietary supplement interactions, with seven patients in Pittsburgh and 12 in Los Angeles having more than three potential drug-dietary supplement interactions. Most of the potential interactions found were with ginseng, garlic, Gingko biloba, and coenzyme Q10.
FDA Announces Qualified Health Claim for Walnuts
The U.S. Food and Drug Administration (FDA) has announced that a qualified health claim soon will appear on product labels for walnuts and the reduced risk of coronary heart disease. This qualified health claim is part of the FDA’s program to provide Americans with better information to help them make healthier dietary choices.
Part of the criteria for making a qualified claim on a conventional food is to provide credible scientific evidence supporting the claim. Based on its evaluation of the available scientific data, as outlined in FDA’s Interim Procedures for Qualified Health Claims in the Labeling of Conventional Human Food and Human Dietary Supplements, the FDA moved forward to allow a qualified health claim for whole and chopped walnuts. The FDA’s review concluded that supportive research shows that walnuts may reduce the risk of coronary heart disease when consumed as part of a low-saturated fat and low-cholesterol diet and not resulting in increased caloric intake. Although this research is not conclusive, FDA believes that consumers will benefit from having information that may help them improve their dietary health.
As a result, consumers will soon see claims on walnuts stating: "Supportive but not conclusive research shows that eating 1.5 oz of walnuts per day, as part of a low-saturated fat and low-cholesterol diet, and not resulting in increased caloric intake may reduce the risk of coronary heart disease. See nutrition information for fat [and calorie] content."
To view the qualified health claim, go to www.cfsan.fda.gov/~dms/qhcnuts3.html.
Researchers at the University of Pittsburgh in Pennsylvania have found that patients who take prescription drugs along with herbal supplements have few adverse reactions. Results of their study were published in the March 22 issue of the Archives of Internal Medicine.
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