Observe Intently (one)pentobarbital will decrease the extent or influence of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep an eye on Intently. Coadministration of fentanyl with CYP3A4 inducers could lead on to your lessen in fentanyl plasma concentrations, insufficient efficacy or, perhaps, advan