butabarbital will reduce the level or impact of nicardipine by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Observe.butabarbital will decrease the extent or outcome of pioglitazone by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Small/Significance Unfamiliar.Teniposide: Barbiturates may possibly decrease the serum fo