pentobarbital increases toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Monitor. CYP3A4 inducers could boost the metabolism of ifosfamide to its Energetic alkylating metabolites.pentobarbital will minimize the level or influence of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Mod