Major
Established
Descrição
Carbamazepine markedly reduces warfarin plasma concentrations, potentially resulting in sub-therapeutic anticoagulation and increased thromboembolic risk.
Mecanismo
Carbamazepine is a potent inducer of CYP2C9 and CYP3A4, the primary enzymes responsible for warfarin metabolism, accelerating its clearance.
Significância Clínica
INR can drop significantly; thrombotic events (stroke, PE) have been reported when warfarin doses were not increased proportionally.
Conduta
Monitor INR closely when initiating or stopping carbamazepine; warfarin dose increases of 50–100% may be required. Consider alternative anticonvulsants if feasible.