Pentobarbital will reduce the extent or influence of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Slight/Importance Not known. pentobarbital will lower the level or outcome of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Observe. pentobarbital will lower the extent or influence of ritonavir by influencing hepatic/intestinal enzyme CY... https://citychemiststore.com/product/buy-nembutal-powder-online/