pentobarbital will lessen the level or influence of buprenorphine buccal by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Watch.pentobarbital will lessen the extent or outcome of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep track of Closely. Coadministration of fentanyl with CYP3A4 in