Butalbital

Butalbital is a barbiturate with an intermediate duration of action. Butalbital is often combined with other medications, such as paracetamol (acetaminophen) (as butalbital/acetaminophen) or aspirin, for the treatment of pain and headache. The various formulations combined with codeine are FDA-approved for the treatment of tension headaches. Butalbital has the same chemical formula as talbutal but a different structure—one that presents as 5-allyl-5-isobutylbarbituric acid.^[3]

Butalbital

Clinical data
Other names	5-allyl-5-isobutylbarbituric acid
AHFS/Drugs.com	Micromedex Detailed Consumer Information
MedlinePlus	a601009
Routes of administration	By mouth
Drug class	Barbiturate
ATC code	none
Legal status
Legal status	BR: Class B1 (Psychoactive drugs)[1] CA: Schedule IV DE: Anlage II (Authorized trade only, not prescriptible) UK: Class B US: Schedule III UN: Psychotropic Schedule III
Pharmacokinetic data
Bioavailability	20-45%
Metabolism	Liver mainly CYP3A4
Elimination half-life	35 hours[2]
Excretion	Kidney
Identifiers
IUPAC name 5-(2-Methylpropyl)-5-(2-propenyl)-2,4,6(1H,3H,5H)-pyrimidinetrione
CAS Number	77-26-9 Y
PubChem CID	2481
IUPHAR/BPS	7138
DrugBank	DB00241 Y
ChemSpider	2387 Y
UNII	KHS0AZ4JVK
KEGG	D03182 Y
ChEBI	CHEBI:102524 Y
ChEMBL	ChEMBL454 Y
CompTox Dashboard (EPA)	DTXSID6022711
ECHA InfoCard	100.000.926
Chemical and physical data
Formula	C11H16N2O3
Molar mass	224.260 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C1NC(=O)NC(=O)C1(CC(C)C)C\C=C
InChI InChI=1S/C11H16N2O3/c1-4-5-11(6-7(2)3)8(14)12-10(16)13-9(11)15/h4,7H,1,5-6H2,2-3H3,(H2,12,13,14,15,16) Y Key:UZVHFVZFNXBMQJ-UHFFFAOYSA-N Y
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Available forms

Combinations include:^{[citation needed]}

• Butalbital/acetaminophen, Butalbital and acetaminophen (paracetamol), (trade names: Axocet, Bucet, Bupap, Cephadyn, Dolgic, Phrenilin, Forte, Sedapap)
• Butalbital/paracetamol/caffeine (trade names: Fioricet, Esgic, Esgic-Plus, Orbivan, Fiormor, Fiortal, Fortabs, Laniroif)
• Butalbital/caffeine/codeine (trade name: Fioricet#3 with Codeine)
• Butalbital/aspirin (trade name: Axotal)
• Butalbital/aspirin/caffeine (trade name: Fiorinal)
• Butalbital/aspirin/caffeine/codeine (trade name: Fiorinal#3 with Codeine)
• Ergotamine/caffeine/butalbital/belladonna alkaloids (trade name: Cafergot-PB)

Contraindications

There are specific treatments which are appropriate for targeting migraines and headaches.^[4] Butalbital is not recommended as a first-line treatment because it impairs alertness, brings risk of dependence and addiction, and increases the risk that episodic headaches will become chronic.^[5] When other treatments are unavailable or ineffective, butalbital may be appropriate if the patient can be monitored to prevent the development of chronic headache.^[5]

Side effects

Side effects for butalbital is usually well tolerated. Commonly reported side effects for butalbital, some of which tend to subside with continued use, include:^{[citation needed]}

• Dizziness
• Respiratory depression
• Drowsiness
• Intoxicated feeling
• Lightheadedness
• Nausea
• Sedation
• Euphoria
• Severe impairment of judgment
• Diarrhea
• Memory Loss
• Constipation

Rare side effects include Stevens–Johnson syndrome, an adverse reaction to barbiturates, and anaphylaxis.

The risk and severity of all side effects is greatly increased when butalbital are combined with other sedatives (e.g., alcohol, opioids, benzodiazepines, antihistamines). Butalbital when taken with sedatives can cause life-threatening respiratory depression and death. Inhibitors of the hepatic enzyme CYP3A4 may also increase the risk, severity, and duration of side effects, many drugs inhibit this enzyme as do some foods such as grapefruit and the blood orange.^{[citation needed]}

Butalbital can cause dependence or addiction.^{[citation needed]}

Interactions

Mixing with alcohol, benzodiazepines, and other depressants increases the risk of intoxication, increases respiratory depression, and increases liver toxicity when in combination with paracetamol (acetaminophen). Use of butalbital and alcohol, benzodiazepines, and other depressants can contribute to coma, and in extreme cases, fatality.^{[citation needed]}