Moderate
Probable
Descripción
Valproic acid can displace warfarin from plasma protein binding sites and may inhibit platelet aggregation, increasing bleeding risk.
Mecanismo
Valproic acid displaces warfarin from albumin binding, transiently raising free warfarin concentrations; it also inhibits platelet aggregation independently through uncertain mechanisms.
Relevancia clínica
Total warfarin levels may appear unchanged while free fraction rises; bleeding risk is increased even without marked INR changes.
Manejo clínico
Monitor INR and clinical signs of bleeding closely when combining; measure free warfarin levels if available. Adjust dose if INR changes.