pentobarbital will lower the level or influence of fentanyl transdermal by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep an eye on Intently. Coadministration of fentanyl with CYP3A4 inducers could lead on to the decrease in fentanyl plasma concentrations, deficiency of efficacy or, probably, advancement of a withdrawa