Potentiation of warfarin's hypoprothrombinemic effect with miconazole vaginal suppositories.

A 53-year-old woman being treated for a vaginal yeast infection experienced ecchymosis. Laboratory evaluation revealed a prolonged prothrombin time. It is possible that the bleeding was due to an interaction between warfarin and miconazole. Health care professionals should be aware of the potential for drug interactions with vaginally administered miconazole, especially in women receiving anticoagulation therapy.