Pentobarbital will reduce the extent or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Slight/Importance Unknown. pentobarbital will reduce the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Watch. pentobarbital will minimize the level or result of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 ... https://citychemiststore.com/product/buy-nembutal-powder-online/