pentobarbital will reduce the extent or result of fosamprenavir by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Keep track of.pentobarbital will decrease the level or outcome of fentanyl transdermal by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Check Closely. Coadministration of fentanyl with CYP