Oxcarbazepine does not affect the anticoagulant activity of warfarin

The possible interaction of the antiepileptic drug oxcarbazepine (OCBZ) on the anticoagulant effect of warfarin was investigated in 10 healthy male volunteers. After reaching steady-state conditions by repeated administration of warfarin, the prothrombin time (Quick value) was assessed before and after single (600 mg) and multiple dosing (450 mg twice daily in 1 week) of OCBZ. In 7 of the 10 volunteers with evaluable data, the prothrombin time was not significantly different (paired t test) from baseline either after single (p = 0.299) or repeated dosing (p = 0.333), indicating that OCBZ does not interact to any relevant extent with the hypothrombinemic effect of warfarin.