Pentobarbital will decrease the level or effect of fosamprenavir by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Observe. pentobarbital will lower the extent or effect of disopyramide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Insignificant/Significance Unidentified. With therapeutic doses of TCAs, barbiturates increase metabolism and reduce bloo... https://masonw775eth3.wikibyby.com/user