pentobarbital improves toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Check. CYP3A4 inducers may well increase the metabolism of ifosfamide to its Lively alkylating metabolites.pentobarbital will decrease the extent or influence of dasatinib by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Us