pentobarbital will lower the extent or influence of fentanyl transmucosal by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep track of Intently. Coadministration of fentanyl with CYP3A4 inducers could lead on to the reduce in fentanyl plasma concentrations, lack of efficacy or, probably, enhancement of the withdrawal syndr