pentobarbital improves toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Observe. CYP3A4 inducers may raise the metabolism of ifosfamide to its Lively alkylating metabolites.pentobarbital will lower the level or influence of copyright topical by affecting hepatic enzyme CYP2B6 metabolism. Insignificant/I