Moderate
Probable
Mô tả
Azithromycin can potentiate the anticoagulant effect of warfarin, leading to elevated INR and increased bleeding risk during and shortly after the antibiotic course.
Cơ chế
Proposed mechanisms include inhibition of CYP1A2 and possible disruption of gut flora that synthesize vitamin K2 (menaquinones), reducing vitamin K availability for clotting factor synthesis.
Ý nghĩa lâm sàng
Case reports and pharmacovigilance data document supratherapeutic INR elevations; major bleeding has been reported.
Xử trí
Monitor INR within 3–5 days of starting and after completing azithromycin; adjust warfarin dose if INR rises above target range.