pentobarbital will decrease the level or effect of clozapine ort affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Datorskärm.pentobarbital increases effects of ifosfamide ort affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Coadministration of ifosfamide with CYP2B6 inducers may increase metabolism of ifosfamide t