pentobarbital will increase toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers might enhance the metabolism of ifosfamide to its Lively alkylating metabolites.pentobarbital will lower the extent or impact of buprenorphine subdermal implant by influencing hepatic/intestinal enzyme