aspirin butalbital caffeine codeine, https://www.amasyamertur.com/. Metabolism and Excretion: Butalbital primarily eliminated by kidneys as unchanged drug or metabolites (59-88% of dose); acetaminophen and caffeine primarily metabolized by liver. Fioricet and Esgic are model title medicine made from a combination of acetaminophen (325 mg), butalbital (a barb...