| Systematic (IUPAC) name | |
|---|---|
| 5-Ethyl-5-(1-methylbutyl)-2,4,6(1H,3H,5H)-pyrimidinetrione | |
| Clinical data | |
| AHFS/Drugs.com | monograph |
| MedlinePlus | a682416 |
| Pregnancy cat. | D (USA) |
| Legal status | USA: Schedule II (oral and parenteral); Schedule III (rectal), UK: Class B Controlled Substance |
| Routes | Oral, Intravenous, Intramuscular, Rectal; also Intraperitoneal & Intracardiac (for animal euthanasia) |
| Pharmacokinetic data | |
| Bioavailability | 70-90% oral; 90% rectal |
| Protein binding | 20-45% |
| Metabolism | Hepatic |
| Half-life | 15-48 hours |
| Excretion | Renal |
| Identifiers | |
| CAS number | 76-74-4 |
| ATC code | N05CA01 QN51AA01 |
| PubChem | CID 4737 |
| DrugBank | APRD01174 |
| ChemSpider | 4575 |
| UNII | I4744080IR |
| KEGG | D00499 |
| ChEBI | CHEBI:7983 |
| ChEMBL | CHEMBL448 |
| Chemical data | |
| Formula | C11H18N2O3 |
| Mol. mass | 226.27 |
| SMILES | eMolecules & PubChem |
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Pentobarbital is a short-acting barbiturate that was first synthesized in 1928. Pentobarbital is available as both a free acid and a sodium salt, the former of which is only slightly soluble in water and ethanol.[1] One brand name for this drug is Nembutal, coined by Dr. John S. Lundy, who started using it in 1930, from the structural formula of the sodium salt—Na (sodium) + ethyl + methyl + butyl + al (common suffix for barbiturates).[2]
Contents |
26.7 g of clean metallic sodium is dissolved in 400 g of anhydrous (dry) ethanol. To this, a solution of 100 g of 1-methylbutyl-ethyl malonic ethyl ester and 37.2 g of dry urea is added. The mixture is heated for 4 to 6 hours in an autoclave, or refluxed for 20 to 40 hours. The alcohol is then removed by distillation. The residue is dissolved in water and this aqueous solution is acidified with hydrochloric acid. The precipitated product is filtered, washed with cold water, and recrystallized from boiling water. Yield depends on one's ability to exclude water from the beginning of the reaction. Melting point is 127°C to 130°C.[3]
Pentobarbital's FDA-approved human uses include treatment of seizures and preoperative (and other) sedation; it is also approved as a short-term hypnotic.[4]
Off-label uses of pentobarbital include reduction of intracranial pressure in Reye's syndrome, traumatic brain injury and induction of coma in cerebral ischemia patients.[4] Pentobarbital-induced coma has been advocated in patients with acute liver failure refractory to mannitol.[5]
In veterinary medicine, sodium pentobarbital is used as an anaesthetic. It is also used by itself, or in combination with complementary agents such as phenytoin, in commercial animal euthanasia injectable solutions. [6]
Pentobarbital has also been used for physician-assisted suicide. In the US state of Oregon "oral doses of a barbiturate" have been used for this purpose.[7]
Also in Switzerland, the only country that allows foreigners to have an assisted death (see Dignitas), and the Netherlands. It was also used in the Northern Territory of Australia, prior to euthanasia becoming illegal in that region.
Pentobarbital has been approved or considered for use in executions in various U.S. states.[8]
The Danish manufacturer of pentobarbital, Lundbeck, expressed displeasure at this use of their product, and on July 1, 2011, announced they would block sales of the drug to U.S. prisons that carry out the death penalty.
Lundbeck is dedicated to saving people’s lives. Use of our products to end lives contradicts everything we are in business to do. Lundbeck is opposed to the use of its product for the purpose of capital punishment.[9]
They explained this decision with their commitment to UN human rights principles. [8]
Pentobarbital undergoes first-pass metabolism in the liver and possibly the intestines.[10]
Administration of alcohol, opioids, antihistamines, other sedative-hypnotics, and other central nervous system depressants will cause possible additive effects.[4]
Pentobarbital is a drug that has been used recreationally.[11]
Pentobarbital is synthesized by methods analogous to that of amobarbital, the only difference being that the alkylation of α-ethylmalonic ester is carried out with 2-bromopentane (not 1-bromo-3-methylbutane) to give pentobarbital.[12][13][14]
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