pentobarbital will decrease the level or outcome of fedratinib by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Outcome of coadministering a powerful CYP3A4 inducer with fedratinib has not been studied.pentobarbital will reduce the extent or result of methadone by affecting hepatic/intestinal enzyme CYP3A4 me