Pentobarbital
Pentobarbital (previously known as pentobarbitone in Britain and Australia) is a short-acting barbiturate typically used as a sedative, a preanesthetic, and to control convulsions in emergencies. It can also be used for short-term treatment of insomnia but has been largely replaced by the benzodiazepine family of drugs.
In high doses, pentobarbital causes death by respiratory arrest. It is used for veterinary euthanasia and is used by some U.S. states and the U.S. federal government for executions of convicted criminals. In some countries and states, it is also used for physician-assisted suicide.Pentobarbital was widely abused and sometimes known as "yellow jackets" due to the yellow capsule of the Nembutal brand. Pentobarbital in oral (pill) form is no longer commercially available.

Uses
Medical
Typical applications for pentobarbital are sedative, short term hypnotic, preanesthetic, insomnia treatment, and control of convulsions in emergencies. Abbott Pharmaceutical discontinued manufacture of their Nembutal brand of Pentobarbital capsules in 1999, largely replaced by the benzodiazepine family of drugs. Pentobarbital was also widely abused, known on the street as "yellow jackets". They were available as 30, 50, and 100-milligram capsules of yellow, white-orange, and yellow colors, respectively.It is also used as a veterinary anesthetic agent.Pentobarbital can reduce intracranial pressure in Reyes syndrome, treat traumatic brain injury and induce coma in cerebral ischemia patients. Pentobarbital-induced coma has been advocated in patients with acute liver failure refractory to mannitol.

Euthanasia
Pentobarbital can cause death when used in high doses. It is used for euthanasia for humans as well as animals. It is taken alone, or in combination with complementary agents such as phenytoin, in commercial animal euthanasia injectable solutions.

In the Netherlands, it is part of the standard protocol for physician-assisted suicide for self-administration by the patient.It is taken by mouth for physician-assisted death in the United States states of Oregon, Washington, Vermont, and California (as of January, 2016).The oral dosage of pentobarbital indicated for physician-assisted suicide in Oregon is typically 10 g of liquid.In Switzerland, sodium pentobarbital is administered to the patient intravenously. Once administered, sleep is induced within 30 seconds, and the heart stops beating within 3 minutes.

Execution
Pentobarbital has been used or considered as a substitute for other drugs previously used for capital punishment in the United States when those drugs are unavailable. Such use however is illegal under Danish law, and when this was discovered, after public outcry in Danish media, Lundbeck, the owner of the drug, stopped selling it to US states that impose the death penalty. US distributors of the drug are forbidden by the owner to sell it to any customers, such as state authorities, that practice or participate in executions of humans.Texas began using pentobarbital for executing death-row inmates by lethal injection on July 18, 2012. The use of pentobarbital has been considered by several states, including Ohio, Arizona, Idaho, and Washington; those states made the decision to switch following shortages of pancuronium bromide, a muscle paralytic previously used as one component in a three-drug cocktail.In October 2013, Missouri changed its protocol to allow for compounded pentobarbital to be used in a lethal dose for executions. It was first used in November 2013.According to a December 2019 ProPublica article, by 2017 the Bureau of Prisons (BOP), in discussion with then Attorney General Jeff Sessions, had begun to search for suppliers of pentobarbital to be used in lethal injections. The BOP was aware that the use of pentobarbital as their "new drug choice" would be challenged in the courts because some lawyers had said that "pentobarbital would flood prisoners’ lungs with froth and foam, inflicting pain and terror akin to a death by drowning." BOP claimed that these concerns were unjustified and that their two expert witnesses asserted that the use of pentobarbital was "humane". On July 25, 2019, US Attorney General William Barr directed the federal government to resume capital punishment after 16 years. The drug of choice for these executions was pentobarbital.

Metabolism
Pentobarbital undergoes first-pass metabolism in the liver and possibly the intestines.

Drug interactions
Administration of ethanol, benzodiazepines, opioids, antihistamines, other sedative-hypnotics, and other central nervous system depressants will cause possible additive effects.

Chemistry
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 in place of 1-bromo-3-methylbutane to give pentobarbital.

Society and culture
Names
Pentobarbital is the INN, AAN, BAN, and USAN while pentobarbitone is a former AAN and BAN.
One brand name for this drug is Nembutal, coined by 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). Nembutal is trademarked and manufactured by the Danish pharmaceutical company Lundbeck (now produced by Akorn Pharmaceuticals) and is the only injectable form of pentobarbital approved for sale in the United States. Abbott discontinued their Nembutal brand of Pentobarbital capsules in 1999, largely replaced by the Benzodiazepine family of drugs. Abbotts Nembutal, known on the streets as "yellow jackets", was widely abused. It was available in 50 and 100 mg strength yellow capsules.Pentobarbital can occur as a free acid, but is usually formulated as the sodium salt, pentobarbital sodium. The free acid is only slightly soluble in water and in ethanol.

See also
Animal euthanasia
List of veterinary drugs

References
External links
"Pentobarbital". Drug Information Portal. U.S. National Library of Medicine.