Medication, butalbital, and acetaminophen are all found in Fioricet pills. Barbiturates is a class of medications that includes butalbital. It relieves tension headaches by relaxing muscle spasms. It improves blood flow by relaxing muscular blood vessels. Fioricet is a pain reliever that is used to manage headaches induced by muscle contractions. Fioricet should not be used for long periods of time because it can induce physical dependence.