pentobarbital will lower the level or impact of prednisone by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Keep track of.pentobarbital improves toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Observe. CYP3A4 inducers may increase the metabolism of ifosfamide to its Energetic alkyl