pentobarbital will decrease the extent or impact of diltiazem by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Watch.pentobarbital will reduce the level or effect of brexpiprazole by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Intently. Double brexpiprazole dose in excess of 1-two weeks if ad