Abstract
The patient was placed on anticoagulant therapy with warfarin after aortic valve replacement. Although it was initially possible to stabilize the international normalized ratio (INR=2.90), the prothrombin time was significantly prolonged (INR=31.39) after intravenous infusion of miconazole for 9 days at a dose of 200mg/day to treat lichen planus. Warfarin therapy was discontinued until the INR decreased to within the acceptable range, which required 14 days, and then warfarin was resumed. A stable INR value was achieved approximately 50 days later. Treatment with miconazole results in significant promotion of the anticoagulant effect of warfarin and a long period was required before normalization of the INR could be achieved in this patient. Accordingly, miconazole therapy should only be indicated in patients receiving treatment with warfarin when administration is essential. Caution should be employed when using this drug in combination with warfarin, and careful monitoring of the bleeding time is necessary.
