Watch Intently (1)pentobarbital will reduce the extent or effect of fentanyl intranasal by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Observe Carefully. Coadministration of fentanyl with CYP3A4 inducers could lead on to some reduce in fentanyl plasma concentrations, lack of efficacy or, possibly, growth of the withdrawal … Read More