pentobarbital will decrease the extent or result of pantoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Importance Unfamiliar.pentobarbital decreases amounts of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. May produce lack of virologic response