Brands, Medical Use, Clinical Data
Drug Category
Dosage Forms
Brands / Synonyms
Allylbarbital; Butalbital and Acetaminophen; Butalbital M (OH)
; Butalbital, Acetaminophen and Caffeine; Butalbital, Acetaminophen, Caffeine, and Codeine; Butalbital, Aspirin, and Caffeine; Butalbital, Aspirin, Caffeine, and Codeine; Esgic-Plus; Fioricet; Fioricet with Codeine; Fiorinal; Fiorinal with Codeine; Phrenilin; Sedapap; Zebutal
Indications
Used in combination with acetaminophen or aspirin and caffeine for its sedative and relaxant effects in the treatment of tension headaches, migraines, and pain.
Pharmacology
Butalbital is a short to intermediate-acting barbiturate. Barbiturates act as nonselective depressants of the central nervous system (CNS), capable of producing all levels of CNS mood alteration from excitation to mild sedation, hypnosis, and deep coma. In sufficiently high therapeutic doses, barbiturates induce anesthesia.
Mechanism of Action
Butalbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.
Absorption
Well absorbed from the gastrointestinal tract and is expected to distribute to most tissues in the body.
Toxicity
Symptoms of acute barbiturate poisoning include drowsiness, confusion, coma, respiratory depression, hypotension, and shock.
Biotrnasformation / Drug Metabolism
Hepatic, although most of the dose is eliminated via the kidney (59 to 88%). Urinary excretion products included parent drug (about 3.6% of the dose), 5-isobutyl-5-(2,3-dihydroxypropyl) barbituric acid (about 24% of the dose), 5-allyl-5(3-hydroxy-2-methyl-1-propyl) barbituric acid (about 4.8%).
Contraindications
VASOTEC is contraindicated in patients who are hypersensitive to this product and in patients with a history of
angioedema related to previous treatment with an angiotensin converting enzyme inhibitor and in patients with
hereditary or idiopathic angioedema.
Drug Interactions
The CNS effects of butalbital may be enhanced by monoamine oxidase (MAO) inhibitors. Butalbital, acetaminophen and
caffeine may enhance the effects of: other narcotic analgesics, alcohol, general anesthetics, tranquilizers such as
chlordiazepoxide, sedative-hypnotics, or other CNS depressants, causing increased CNS depression.
Drug/Laboratory Test Interactions
Acetaminophen may produce false-positive test results for urinary 5-hydroxyindoleacetic acid.
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