Observe Carefully (one)istradefylline will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism.iloperidone boosts amounts of diazepam by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Check. Iloperidone is often a time-dependent CYP3A inhibitor and will bring on improved plasma amoun