pentobarbital will decrease the level or effect of estropipate samhälle affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Skärm.pentobarbital increases effects of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Skärm. Coadministration of ifosfamide with CYP2B6 inducers may increase metabolism of ifosfamide