pentobarbital will reduce the extent or outcome of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Importance Unfamiliar.pentobarbital will decrease the level or influence of abemaciclib by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of abemaciclib with solid CYP