|By mouth, IV, IM, rectal; also intraperitoneal & intracardiac (for animal euthanasia)|
|Bioavailability||70–90% (oral); 90% (rectal)|
|Elimination half-life||15–48 hours|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||226.276 g·mol−1|
|3D model (JSmol)|
Pentobarbital, also known as pentobarbitone, is a short-acting barbiturate. In high doses, pentobarbital causes death by respiratory arrest. In the United States, the drug has been used for executions of convicted criminals. Lundbeck (one of many manufacturers) does not permit its sale to prisons or corrections departments to carry out the death penalty. Abbott Pharmaceuticals brand of pentobarbital, Nembutal, which was available in 50 and 100 mg yellow capsules was discontinued in 1999. Prescribed for insomnia, it has been largely replaced by the benzodiazepine family of drugs. Nembutal was widely abused and known on the streets as "yellow jackets" due to their yellow capsule. Pentobarbital in pill form is no longer available. The death of Marilyn Monroe in 1962 was ruled as probable suicide due to an overdose of Nembutal.
Typical applications for pentobarbital are sedative, hypnotic for short term, preanesthetic, insomnia, 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 streets as "yellow jackets". They were available in 50 and 100 mg. yellow capsules. Pentobarbital in pill form is no longer manufactured.
It is also used as a veterinary anesthetic agent.
Pentobarbital also has an application in reducing intracranial pressure in Reye's syndrome, traumatic brain injury and induction of coma in cerebral ischemia patients. Pentobarbital-induced coma has been advocated in patients with acute liver failure refractory to mannitol.
Pentobarbital can cause 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 to provide 9 grams of pentobarbital sodium along with sugar syrup in a 20% ethanol solution for self-administration by the patient.
The oral dosage of pentobarbital indicated for physician-assisted death in the United States states of Oregon, Washington, Vermont, and California (as of January, 2016) is typically 10 g in liquid form. This is considerably higher than the dose for the management of status epilepticus.
Pentobarbital has been used or considered as a substitute for other drugs traditionally used for capital punishment in the United States when they are in short supply. 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 several 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.
On July 25, 2019, Attorney General William Barr directed the federal government to resume capital punishment after 16 years. The drug of choice for these executions is pentobarbital.
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.
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. Abbott's Nembutal brand of Pentobarbital capsules were widely abused and were known on the streets as "yellow jackets". They were available in 50 and 100 Mg.strength yellow capsules.