Moderate
Probable
Descrição
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.
Significância Clínica
Total warfarin levels may appear unchanged while free fraction rises; bleeding risk is increased even without marked INR changes.
Conduta
Monitor INR and clinical signs of bleeding closely when combining; measure free warfarin levels if available. Adjust dose if INR changes.