pentobarbital will decrease the level or impact of ketoconazole by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Importance Unknown.pentobarbital will lower the extent or impact of doxorubicin by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Warning/Keep an eye on.Contraindicated (one)pentobarbital will lower the lev