Pentobarbital
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| 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 | UN:Schedule IIIUSA: 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 | DB00312 |
| ChemSpider | 4575 |
| UNII | I4744080IR |
| KEGG | D00499 |
| ChEBI | CHEBI:7983 |
| ChEMBL | CHEMBL448 |
| Chemical data | |
| Formula | C11H18N2O3 |
| Mol. mass | 226.27 |
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Pentobarbital (US English) or pentobarbitone (UK English) is a short-acting barbiturate that was first synthesized in 1928. Pentobarbital can occur as both a free acid and salts such as sodium and calcium. The free acid is only slightly soluble in water and ethanol.[1][2]
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).[3]
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Uses [edit]
Medical [edit]
Typical applications for pentobarbital are sedative, hypnotic for short term, preanesthetic and control of convulsions in emergencies.[4]
It is also used as a veterinary anesthetic agent.[5]
Pentobarbital also has an application in reducing intracranial pressure in Reye's syndrome, traumatic brain injury and induction of coma in cerebral ischemia patients.[6] Pentobarbital-induced coma has been advocated in patients with acute liver failure refractory to mannitol.[7]
Euthanasia [edit]
Pentobarbital can induce death when used in high doses. It is used for euthanasia for humans as well as animals.
It is also used by itself, or in combination with complementary agents such as phenytoin, in commercial animal euthanasia injectable solutions.
In the Netherlands, the standard protocol for physician-assisted suicide is intravenously induced thiopental anesthesia, followed by bromide of alcuronium or pancuronium induced respiratory arrest. A concentrated oral solution of 100 ml containing 9 grams of pentobarbital sodium along with sugar syrup in a 20% ethanol solution is a standard solution used for self administration by patient.[8]
The dosage of pentobarbital indicated for physician-assisted suicide in Oregon, US is typically 10 g in liquid form.[9]
Capital punishment [edit]
Pentobarbital has been used or considered as a substitute for other drugs traditionally used in the United States for execution when they are in short supply.[10] Texas executed its first death row inmate with a lethal injection of the sedative pentobarbital on July 18, 2012.[11] The use of pentobarbital may become more widespread after several states, including Ohio, Arizona, Idaho and Washington made the decision to switch following shortages of the pancuronium bromide, a muscle relaxant previously used as one component in a 3-drug cocktail.[12][unreliable source?]
Metabolism [edit]
Pentobarbital undergoes first-pass metabolism in the liver and possibly the intestines.[13]
Drug interactions [edit]
Administration of alcohol, opioids, antihistamines, other sedative-hypnotics, and other central nervous system depressants will cause possible additive effects.[6]
Recreational use [edit]
Pentobarbital is a drug that has been used recreationally.[14]
Chemistry [edit]
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.[15][16][17]
References [edit]
- ^ "Pentobarbital Compound summary (CID4737)". Pubchem. NCBI.
- ^ FR1972_08_25_17226. Food and Drug Administration.
- ^ Fosburgh, L. C. (1997). "From this point in time: Some memories of my part in the history of anesthesia--John S. Lundy, MD". AANA journal 65 (4): 323–328. PMID 9281913.
- ^ "NEMBUTAL SODIUM (pentobarbital sodium) injection, solution". DailyMed, National Institutes of Health.
- ^ "International". Drugs.com.
- ^ a b "Pentobarbital". Monograph. AHFS / Drugs.com.
- ^ Stravitz, R. T.; Kramer, A. H.; Davern, T.; Shaikh, A. O. S.; Caldwell, S. H.; Mehta, R. L.; Blei, A. T.; Fontana, R. J. et al. (2007). "Intensive care of patients with acute liver failure: Recommendations of the U.S. Acute Liver Failure Study Group". Critical Care Medicine 35 (11): 2498–2508. doi:10.1097/01.CCM.0000287592.94554.5F. PMID 17901832.
- ^ "Euthanica". Euthanesia Dossier (in Dutch). NRC Webpagina's.
- ^ Jennifer Fass and Andrea Fass (2011). "Physician-assisted Suicide: Ongoing Challenges for Pharmacists". Am J Health Syst Pharm 68 (9): 846–849.
- ^ "States urge feds to help import lethal injection drugs". CNN. May 21, 2012.
- ^ "Texas executes Yokamon Hearn with pentobarbitol". BBC News. 18 July 2012.
- ^ "Texas executes Yokamon Hearn". Retrieved 20 July 2012.
- ^ Knodell, R. G.; Spector, M. H.; Brooks, D. A.; Keller, F. X.; Kyner, W. T. (1980). "Alterations in pentobarbital pharmacokinetics in response to parenteral and enteral alimentation in the rat". Gastroenterology 79 (6): 1211–1216. PMID 6777235.
- ^ Griffiths, R. R.; Johnson, M. W. (2005). "Relative abuse liability of hypnotic drugs: A conceptual framework and algorithm for differentiating among compounds" (pdf). The Journal of Clinical Psychiatry 66 (Suppl 9): 31–41. PMID 16336040.
- ^ Volwiler, E. H.; Tabern, D. L. (1930). "5,5-SUBSTITUTED BARBITURIC ACIDS". Journal of the American Chemical Society 52 (4): 1676–1679. doi:10.1021/ja01367a061.
- ^ German imperial patent, D.R.P. 293163 (1916), Bayer
- ^ GB patent 650354, Wilde, B. E. & Balaban, I. E., "Improvements in the manufacture of substituted barbituric and thiobarbituric acids", issued 1951-02-21, assigned to Geigy
External links [edit]
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