Contraindicated (1)pentobarbital will lower the extent or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. CYP3A4 is accountable for the formation and elimination of cariprazine's Lively metabolites.pentobarbital improves effects of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Warning