Study on Medicinal and Supplemental Use
The majority of adults in the United States takes at least one prescription medication or nutritional or herbal supplement per week, and many are taking multiple substances, according to a new survey in the Journal of the American Medical Association.1 There has been growing concern regarding the safety of taking prescription and over-the-counter (OTC) medications with nutritional supplements or herbs, since little is known about how these compounds interact. As many natural products are self-prescribed, this new information may help increase awareness about potential drug-nutrient and drug-herb interactions.
Researchers interviewed 2,590 people over age 18 about their use of prescription and nonprescription medications, vitamins/minerals, and herbals/nonvitamin supplements during the preceding week. They were asked the reason for taking the medication, and the type and frequency of medication used. The results showed that 81% of all participants used at least one of these substances. Half of those interviewed were taking at least one prescription drug and 7% had taken more than five in the previous week. The top three prescription or OTC medications used were acetaminophen (Tylenol®), ibuprofen (Advil®) and aspirin. Use of medications increased with age and was greater in women than in men.
The authors also found that 40% of the people took a vitamin/mineral supplement, while 14% had used an herbal/nonvitamin supplement in the prior week. The most popular vitamins used included a multivitamin (26%), vitamin E (10%), vitamin C (9%), and calcium (9%). Herbs and nonvitamin supplements most frequently taken included ginseng, ginkgo, garlic, glucosamine sulfate, and St. John’s wort. Middle-aged people of both sexes reported higher use of these compounds, compared with those younger and older. The most common reason indicated for using both vitamins/minerals and herbals/nonvitamin supplements was for health benefits.
An interesting finding was that 16% of prescription drug users stated that they took at least one nutritional or herbal supplement. Participants listed high blood pressure, headache, heart condition, allergies, and pain as the top reasons for taking prescription medications. With one out of six users of prescription medications also taking a vitamin or herbal supplement, it is possible that some of these people are taking a harmful combination. For example, St. John's wort may reduce the effectiveness of certain drugs, such as warfarin, digoxin, theophylline, cyclosporine, and oral contraceptives,2 and multiple vitamins that contain vitamin K can interfere with the effect of warfarin. On the other hand, beneficial interactions can occur, as well; for example, taking 500 mcg of folic acid per day can increase the efficacy and reduce the side effects of fluoxetine (Prozac®).3 To be on the safe side, anyone taking a prescription or OTC medication should consult his or her physician before starting a nutritional supplement program.
1. Kaufman DW, Kelly JP, Rosenberg L, et al. Recent patterns of medication use in the ambulatory adult population of the United States. JAMA 2002;287:337–44.
2. Biffignandi PM, Bilia AR. The growing knowledge of St. John's wort (Hypericum perforatum L) drug interactions and their clinical significance. Curr Ther Res 2000;61:389–94.
3. Coppen A, Bailey J. Enhancement of the antidepressant action of fluoxetine by folic acid: a randomised, placebo controlled trial. J Affect Disord 2000;60:121–30.
Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of Garlic and Cholesterol: Everything You Need to Know (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice in Westport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.
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