pentobarbital will decrease the level or effect of doxorubicin by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Check.Anticoagulants: Phenobarbital lowers the plasma levels of dicumarol (title Earlier used: bishydroxycoumarin) and results in a lower in anticoagulant activity as calculated because of the prothrombin time. Barbit