Moderate
Established
Descripción
Ciprofloxacin consistently enhances warfarin's anticoagulant effect, raising INR and increasing the risk of bleeding complications.
Mecanismo
Ciprofloxacin inhibits CYP1A2, reducing the metabolism of R-warfarin; it also suppresses gut flora, diminishing intestinal vitamin K production.
Relevancia clínica
Clinically significant INR elevations occur in a substantial proportion of patients; GI and urinary tract bleeding have been documented.
Manejo clínico
Check INR 3–5 days after starting ciprofloxacin and after completing the course; reduce warfarin dose empirically by ~10–15% if INR trending up.