Watch Closely (1)phenobarbital will decrease the level or influence of fentanyl transmucosal by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep track of Carefully. Coadministration of fentanyl with CYP3A4 inducers may lead to some minimize in fentanyl plasma concentrations, lack of efficacy or, potentially, improvement of… Read More