Keep track of Intently (one)phenobarbital will minimize the extent or impact of fentanyl transmucosal by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep an eye on Intently. Coadministration of fentanyl with CYP3A4 inducers could lead to the reduce in fentanyl plasma concentrations, lack of efficacy or, potentially, develo