Mô tả
Clindamycin may enhance the anticoagulant effect of warfarin by disrupting vitamin K-producing gut flora, leading to unpredictable INR elevations and increased bleeding risk during and shortly after the antibiotic course.
Cơ chế
Clindamycin has broad activity against anaerobic gut bacteria that synthesise menaquinones (vitamin K2); reduction in gut flora vitamin K production augments warfarin's anticoagulant effect without altering warfarin pharmacokinetics directly.
Ý nghĩa lâm sàng
Case reports and observational data associate clindamycin use with supratherapeutic INR values in anticoagulated patients; the magnitude is variable and difficult to predict.
Xử trí
Monitor INR within 3–5 days of starting clindamycin; reduce warfarin dose if INR rises above the therapeutic range; maintain consistent dietary vitamin K intake during antibiotic therapy.