Skip to content

warfarin

Interactions

Rifamycins/Anticoagulants

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

When these two medicines are taken together, your body may process your blood-thinning medicine more quickly.

What might happen:

The effects of your blood-thinner may decrease and increase your risk for blood clots. If your rifamycin is stopped, there is an increased chance for bleeding.

What you should do about this interaction:

Contact your healthcare professionals (e.g. doctor or pharmacist) about taking these two medicines together. They may already be aware of this interaction and may be monitoring you for it. For some anticoagulants, your doctor may want to check your bleeding times more often. Your dose of blood-thinner may need adjusting, especially if your doctor stops your rifamycin. If you experience bleeding from your gums, nosebleeds, unusual bruising, or dark stools, contact your doctor. Do not start, stop, or change the dosage of any medicine before checking with them first.

References:

1.Heimark LD, Gibaldi M, Trager WF, O'Reilly RA, Goulart DA. The mechanism of the warfarin-rifampin drug interaction in humans. Clin Pharmacol Ther 1987 Oct;42(4):388-94.

2.O'Reilly RA. Interaction of sodium warfarin and rifampin. Studies in man. Ann Intern Med 1974 Sep;81(3):337-40.

3.O'Reilly RA. Interaction of chronic daily warfarin therapy and rifampin. Ann Intern Med 1975 Oct;83(4):506-8.

4.Lee CR, Thrasher KA. Difficulties in anticoagulation management during coadministration of warfarin and rifampin. Pharmacotherapy 2001 Oct; 21(10):1240-6.

5.Fox P. Warfarin-rifampicin interaction. Med J Aust 1982 Jan 23;1(2):60.

6.Self TH, Mann RB. Interaction of rifampin and warfarin. Chest 1975 Apr; 67(4):490-1.

7.Romankiewicz JA, Ehrman M. Rifampin and warfarin: a drug interaction. Ann Intern Med 1975 Feb;82(2):224-5.

8.Held H. Interaction of rifampicin with phenprocoumon (author's transl). Dtsch Med Wochenschr 1979 Sep 14;104(37):1311-4.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

More about Drugs and Medications

Newsletters

Subscribe to free WebMD newsletters.

  • WebMD Daily

    WebMD Daily

    Subscribe to the WebMD Daily, and you'll get today's top health news and trending topics, and the latest and best information from WebMD.

  • Men's Health

    Men's Health

    Subscribe to the Men's Health newsletter for the latest on disease prevention, fitness, sex, nutrition, and more from WebMD.

  • Women's Health

    Women's Health

    Subscribe to the Women's Health newsletter for the latest on disease prevention, fitness, sex, diet, anti-aging, and more from WebMD.

By clicking Submit, I agree to the WebMD Terms & Conditions & Privacy Policy

URAC: Accredited Health Web Site TRUSTe online privacy certification HONcode Seal AdChoices