Hyperprothrombinemia as a result of a possible warfarin and intravaginal miconazole interaction.
Author(s): Thomas JL, Dunn D, Pelletier A, Franks AS
Affiliation(s): Department of Pharmacy Practice, University of Arkansas for Medical Sciences, Little Rock, AR, USA. jlthomas2@uams.edu
Publication date & source: 2010-10, South Med J., 103(10):1063-5.
Publication type: Case Reports
Warfarin, a commonly prescribed anticoagulant, has many potential drug interactions. We describe a case of intravaginal miconazole potentiating the effects of warfarin in a patient previously stable on a consistent dose of 8.5 mg warfarin daily. Following a course of intravaginal miconazole and a dosage increase to 9 mg daily, her international normalized ratio (INR) increased from 2.0 to 5. After the course of miconazole was complete, the patient was stable with a therapeutic INR (mean INR 2.9) on 9 mg warfarin daily. Clinicians should consider the possibility of systemic absorption of intravaginal miconazole, and a resultant increase in warfarin's anticoagulant effect.
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