pentobarbital will reduce the extent or effect of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism.pentobarbital will lower the extent or influence of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Steer clear of or Use Alternate Drug. Coadministration of abemaciclib with sturdy CYP3A4 inducers decreases pla