Keep an eye on Closely (one)pentobarbital will improve the amount or impact of clopidogrel by impacting hepatic/intestinal enzyme CYP3A4 metabolism.pentobarbital will decrease the extent or result of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Keep track of Intently. Potent or average CYP3A4 inducers substant