FDA is advising women who take the prescription blood-thinner warfarin to consult their doctor or pharmacist for advice before using an OTC vaginal miconazole product.

FDA has also advised manufacturers of vaginal creams and suppositories containing miconazole to add a new warning to the Drugs Facts box on product labels. The warning states: Ask a doctor or pharmacist before use if you are taking the prescription blood thinning medicine warfarin, because bleeding or bruising may occur.

FDA is taking this action because the agency has received two adverse events indicating abnormal blood clotting tests with women who took anticoagulant therapy and used vaginal miconazole. In addition to abnormal tests, one woman developed bruises, bleeding gums and a nosebleed. Two articles from medical journals reported cases of probable warfarin interaction with vaginal miconazole. The agency believes that consumers should have all the information about a drugيs potential risks before deciding to use it.

Miconazole is an antifungal drug that has been available by prescription and over-the-counter in different forms such as creams and suppositories for many years. The vaginal creams and suppositories are used to treat vaginal yeast infections.
The interaction of systemically administered miconazole with warfarin is well established, and is included in the warfarin labeling.

Because of the concerns raised by the recent reports of an interaction with vaginally administered miconazole with warfarin, physicians and patients should be aware that patients who need to use both products simultaneously should be appropriately monitored. In addition to being placed on the product labels, the new label will be included in consumer brochures. Products containing miconazole include the recently approved Monistat combination pack.