butabarbital boosts effects of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Keep an eye on. CYP3A4 inducers may well increase the metabolism of ifosfamide to its active alkylating metabolites.butabarbital will decrease the extent or effect of lumefantrine by impacting hepatic/intestinal enzyme CYP3A4 metabolism