butabarbital raises consequences of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Watch. CYP3A4 inducers may enhance the metabolism of ifosfamide to its Lively alkylating metabolites.butabarbital will decrease the extent or effect of paclitaxel protein sure by influencing hepatic/intestinal enzyme CYP3A4 metabol