pentobarbital will reduce the level or effect of nisoldipine by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Check.pentobarbital will increase effects of ifosfamide by impacting hepatic enzyme CYP2B6 metabolism. Use Warning/Check. Coadministration of ifosfamide with CYP2B6 inducers may perhaps raise metabolism of ifosfamide