Metabolism and Excretion: Butalbital primarily eradicated by kidneys as unchanged drug or metabolites (59-88% of dose); acetaminophen and caffeine primarily metabolized by liver. Fioricet and Esgic are brand name medication made from a mixture of acetaminophen (325 mg), butalbital (a barbiturate, 50 mg), and caffeine (forty mg). Also important when wanting o...