phenobarbital boosts toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Watch. CYP3A4 inducers might improve the metabolism of ifosfamide to its Lively alkylating metabolites.The average day by day dose for the barbiturate addict is frequently about one.five g. As tolerance to barbiturates develops, the q