Contraindicated (one)pentobarbital will minimize the extent or impact of cariprazine by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. CYP3A4 is responsible for the formation and elimination of cariprazine's Energetic metabolites.Following halting a CYP3A4 inducer, as the effects on the inducer decrease, the fentanyl plasma