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