pentobarbital will reduce the level or impact of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Check.pentobarbital will minimize the extent or outcome of mifepristone by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Watch. CYP3A4 inducers haven't been studied, coadministration not suggested by