Patients taking herbal remedies, and who are taking warfarin as well, need to be monitored closely for signs of increased bleeding or other side effects. Common remedies such as garlic, ginkgo, red clover, ginger and willow bark all have anti-clotting properties and may increase the risk of bleeding, according to a report by researchers at Purdue University, in Indianapolis, Indiana. Other remedies including vitamin E, devil's claw and dong quai may enhance warfarin's effects. On the other hand, green tea, coenzyme Q10 and ginseng have properties that make them likely to decrease warfarin's effects. The report highlights 38 herbal treatments, which have the potential to interact with warfarin. According to the authors, more food and drug interactions have been reported for warfarin than for any other prescription medication.
Much of the data pertaining to these interactions are unclear, and some may depend on the dose or the form of the herb being taken. While there have been no reports of potentiation of warfarin's activity with garlic supplements, the available information suggests that a serious interaction is possible. However, a preliminary clinical trial that is soon to be published found no contraindication for taking aged garlic extract and warfarin together. The authors suggest that patients on warfarin who are also taking more than 400 IU per day of vitamin E be monitored for changes in blood clotting time. The bottom lineÖbe sure to tell your physician, dietitian or pharmacist about all supplements and/or medications you are taking. Before taking a new herbal remedy ask your pharmacist if there are interactions with your medication(s).
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.