点击显示 收起
July 11, 2000 -- With an estimated one-third of U.S. adults now using herbal remedies, a typical medicine cabinet today might just as likely contain a bottle of St. John's wort or ginkgo biloba as a bottle of aspirin.
The prevalence of herbal remedies, combined with a recent article about the potential interaction between these herbal remedies and prescription drugs, highlights the importance of telling your physician about any herbal remedies you are using.
The article, published in a recent issue of American Journal of Health System Pharmacy, suggests that as alternative medicines continue to gain popularity, interactions with prescription medications may become more likely. This may already be happening with one of the most widely prescribed blood thinners, called Coumadin or warfarin, according to the article.
"This is a potentially huge problem," cardiologist Brian Olshansky, MD, tells WebMD. "Ginkgo biloba, for example, has been shown to inhibit [blood clotting] activity. The combination of Coumadin and ginkgo could potentially be very serious. As far as I know there have been no reported deaths from the combination, but the risk of bleeding is quite high with Coumadin alone, so these deaths could easily be missed."
Experts contacted by WebMD say it is impossible to tell how widespread a problem this is for two reasons: patients rarely tell their doctors about the alternative medicines they take, and there have, as yet, been no large studies to address the issue. They stress the need for you to remember to always tell your doctor what medications -- alternative or otherwise -- you're taking.
"Clearly there is interaction between Coumadin and many of these herbal medicines, but we're not really sure how big a problem this is," says Olshansky. "It's true that most people don't tell their doctors exactly which herbal therapies they are on, but even if they do, the doctor doesn't know what to tell the patient." Olshansky is director of cardiac electrophysiology at the University of Iowa and is an expert on alternative medicines.
Michael Lin, MD, program director for the National Institutes of Health's National Heart, Lung, and Blood Institute, agrees that both patients and physicians need more information on the interaction between widely prescribed drugs like Coumadin and the ever-expanding group of herbal products being sold for medicinal purposes.
"Some of these alternative medicines have been around for hundreds of years, but we don't know much about them from a scientific standpoint," he tells WebMD.
Coumadin is an anticoagulant that is often given to patients following heart attacks or strokes to prevent blood clots. Because Coumadin interacts with more foods and drugs than many other medications, researchers at Indianapolis' Purdue University Pharmacy Programs conducted a review to see how it might interact with alternative therapies.
If interaction with Coumadin increases the drug's activity, you could suffer from excessive bleeding. If its effectiveness is lessened, you could get blood clots.
Researcher Amy M. Heck, PharmD, and colleagues found that three alternative medicines -- coenzyme Q10, ginseng, and green tea -- have been shown to decrease the effectiveness of Coumadin as a blood thinner. Five other medicines -- vitamin E, papain, dong quai, devil's claw, and danshen -- all have been shown to increase the blood thinning properties of Coumadin, perhaps to dangerous levels.
The authors also list about 30 other herbal remedies, including ginkgo biloba, sweet clover, tumeric, borage seed oil, feverfew, garlic, ginger, and angelica root, as having the potential, but still unproven, ability to increase the risk of bleeding in patients taking Coumadin.
But because most of the papers found by the researchers involved either laboratory data, animal studies, or individual case reports, no definitive conclusions could be made. The authors call on physicians to question their patients about alternative therapy use and report suspected interactions to the FDA's MedWatch program.
Vital Information: