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Are there any drug interactions with Coumadin?

Coumadin (generic name warfarin) is an anticoagulant, a drug that makes it harder for the body to make blood clots. There is a very large list of prescription, over-the-counter, and herbal medicines can interact with Coumadin. Taking Coumadin with these medicines can increase your risk of bleeding or forming blood clots. Be sure to let your health care provider know about all of the prescription or over-the-counter products that you take in addition to your Coumadin.

You should avoid over-the-counter pain relievers containing aspirin, ibuprofen (brand name Motrin, Advil), ketoprofen (Orudis), or naproxen (Aleve). Combining these pain relievers with your Coumadin can increase your risk for bleeding. You may safely take acetaminophen (>Tylenol) products occasionally for minor aches and pains.

Several herbs and supplements can also interact with Coumadin. They include dong quai, feverfew, garlic, ginger, ginkgo, ginseng, smartweed, and st. john’s wort. Be sure to check with your health care provider before taking any over-the-counter products, herbal remedies, supplements, or vitamins.

Foods high in vitamin K—such as broccoli and kale—may interfere with the actions of Coumadin. Because these foods are an important part of a healthy diet, don’t avoid them completely. But be careful to eat them in moderation and avoid making big changes in your diet. You should also avoid excessive alcohol intake and binge drinking. If you do make a major change in your diet or in the amount of alcohol you drink, be sure to tell your health care provider.

Sources:
Micromedex® Healthcare Series. Thomson Micromedex, 2006.
Miller, L.G. "Herbal Medicinals: Selected Clinical Considerations Focusing on Known or Potential Drug-Herb Interactions," Archives of Internal Medicine 158 (1998).
Hansten, P. D., J. R. Horn. Drug Interactions Analysis and Management. Applied Therapeutics, 2000.
Drug Facts and Comparisons. Facts & Comparisons, 2006.

This answer prepared 1/11/2001.
This information updated 12/05/2006.