phenobarbital increases toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Monitor. CYP3A4 inducers may enhance the metabolism of ifosfamide to its Energetic alkylating metabolites.This mechanism is probably in the induction of hepatic microsomal enzymes that metabolize the antibiotic. If phenobarbital an… Read More