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A bottle of butalbital/acetaminophen
Combination of
AcetaminophenMiscellaneous analgesic
Clinical data
Trade namesAllzital, Butapap, Fioricet, others
AHFS/Drugs.comProfessional Drug Facts
License data
Routes of
By mouth
ATC code
  • None
Legal status
Legal status
CAS Number
  • 77-26-9
  • none

Butalbital/acetaminophen, sold under the brand name Butapap among others, is a combination medication used to treat tension headaches and migraine headaches.[1][2][3] It contains butalbital, a barbiturate and paracetamol (acetaminophen), an analgesic.[2] Versions also containing caffeine are sold under the brand name Fioricet among others.[4] It is taken by mouth.[2][5] The combination is also sold with codeine.[6]

The most common side effects include sleepiness, dizziness, trouble breathing, and abdominal pain.[2] Other severe side effects may include liver problems, confusion, addiction, and allergic reactions.[2] Frequent use may result in medication overuse headache.[7] Barbiturate withdrawal may occur if rapidly stopped following long term use.[8] Use is not generally recommended during pregnancy or breastfeeding.[9]

The combination was approved for medical use in the United States in 1984.[2] It is available as a generic medication.[4] In 2018, it was the 184th most commonly prescribed medication in the United States, with more than 3 million prescriptions.[10][11] In the United States it is a schedule III controlled substance[12] in some states but not federally.[3][13][14] It is banned in a number of European countries.[8]

Medical uses[edit]

Butalbital/acetaminophen is indicated for the treatment of tension headaches. It is also commonly prescribed for migraines, although it is not approved by the FDA for this. The usual adult dose is one to two tablets every four hours as needed, not to exceed six tablets in a twenty-four-hour period.[5]

Side effects[edit]

Commonly reported side effects include euphoria, dizziness or lightheadedness, drowsiness or sedation, intoxication, nausea, vomiting, dependence, shortness of breath, and abdominal pain.[citation needed]

Prolonged use can cause rebound headaches.[15]

Rarely, use of barbiturates can lead to Stevens–Johnson syndrome.[citation needed]


Butalbital exerts its toxicity through excessive sedation, resulting in respiratory depression and ultimately death via hypoxia. Nonlethal overdoses may also result in coma and death. There is no specific antidote to barbiturate overdose; treatment is supportive, generally including the administration of intravenous saline, naloxone, thiamine, glucose, sodium bicarbonate to alkalize the urine and increase rate of excretion, and activated charcoal via nasogastric tube.[citation needed]

Acetaminophen exerts its toxicity through the production of a toxic metabolite that can cause liver damage at doses as low as four grams. Larger doses can precipitate acute liver failure, acute kidney injury, or gastrointestinal bleeding; death has been known to occur with ingestion of ten to fifteen grams. The specific antidote to acetaminophen overdose is N-acetylcysteine.[citation needed]

Mechanism of action[edit]

Butalbital exerts a generalized depressant effect on the central nervous system and, in very high doses, has peripheral effects.[citation needed] Acetaminophen has analgesic and antipyretic effects mediated by a metabolite that acts at cannabinoid receptors.[dubious ][citation needed] Caffeine is thought to produce constriction of cerebral blood vessels and serves to counteract the sedative effect of butalbital.[citation needed]

Butalbital has a half-life of about 35 hours. Acetaminophen has a half-life of about 1.25 to 3 hours, but may be increased by liver damage and after an overdose. Caffeine has a half-life of about 2.5 to 4.5 hours.[16]


Fiorcet historically contained 50 mg of butalbital, 40 mg of caffeine, and 325 mg of acetaminophen per dose. However, in accordance with FDA guidelines advising manufacturers to limit doses of acetaminophen in prescription drugs,[17] the acetaminophen content was lowered to 300 mg as of 2014.[18][19]

Fioricet is also available in a formulation containing 30 mg of codeine per dose.[6]


  1. ^ "Butapap- butalbital and acetaminophen tablet". DailyMed. 17 January 2020. Retrieved 10 April 2020.
  2. ^ a b c d e f "Butalbital and Acetaminophen - FDA prescribing information, side effects and uses". Drugs.com. Retrieved 18 April 2019.
  3. ^ a b "Fioricet Capsules (acetaminophen/butalbital/caffeine)". Prescribers' Digital Reference. Retrieved 18 April 2019.
  4. ^ a b Hamilton RJ (2009). Pharmacopoeia. Jones & Bartlett Learning. p. 3. ISBN 9780763774196.
  5. ^ a b "Fioricet- butalbital, acetaminophen, and caffeine capsule". DailyMed. 27 January 2020. Retrieved 10 April 2020.
  6. ^ a b "Fioricet with Codeine- butalbital, acetaminophen, caffeine, and codeine phosphate capsule". DailyMed. 7 February 2020. Retrieved 10 April 2020.
  7. ^ Woo TM, Robinson MV (2015). Pharmacotherapeutics For Advanced Practice Nurse Prescribers. F.A. Davis. p. 1057. ISBN 9780803645813.
  8. ^ a b Young WB, Siow HC (April 2002). "Should butalbital-containing analgesics be banned? Yes". Current Pain and Headache Reports. 6 (2): 151–5. doi:10.1007/s11916-002-0012-y. PMID 11872187. S2CID 20095800.
  9. ^ "Acetaminophen / butalbital Use During Pregnancy". Drugs.com. Retrieved 18 April 2019.
  10. ^ "The Top 300 of 2021". ClinCalc. Retrieved 18 February 2021.
  11. ^ "Acetaminophen; Butalbital - Drug Usage Statistics". ClinCalc. Retrieved 18 February 2021.
  12. ^ "Allzital- butalbital and acetaminophen tablet". DailyMed. 17 December 2019. Retrieved 18 April 2020.
  13. ^ "West Virginia Board of Pharmacy" (PDF). Retrieved 8 June 2019.
  14. ^ "Butalbital". Drugs Details. Retrieved 18 April 2020.
  15. ^ A Hidden Cause of Headache Pain - New York Times
  16. ^ Willis B, Lopez G, Patel K, Frank K (7 October 2019). "Caffeine". Examine.com Inc.
  17. ^ "FDA drug safety communication: prescription acetaminophen products to be limited to 325 mg per dosage unit; boxed warning will highlight potential for severe liver failure". U.S. Food and Drug Administration. 18 June 2019.
  18. ^ "Fioricet package insert Cardinal Health, Inc". DailyMed. U.S. National Library of Medicine. Old formulation
  19. ^ "Fioricet package insert, Watson Pharma, Inc". DailyMed. U.S. National Library of Medicine. New formulation

External links[edit]