pentobarbital will reduce the extent or influence of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Observe Intently. Coadministration of fentanyl with CYP3A4 inducers may lead to a decrease in fentanyl plasma concentrations, not enough efficacy or, possibly, improvement of a withdrawal syndrome in a v… Read More