Sodium thiopental

{{Short description|Barbiturate general anesthetic}} {{Distinguish|pentobarbital|phenobarbital}} {{Redirect2|Sodium Pentathol|C11 H17 N2 O2 S Na|the song by Anthrax|Sound of White Noise}} {{Use dmy dates|date=September 2025}} {{cs1 config|name-list-style=vanc|display-authors=6}} {{Infobox drug | image = Sodium thiopental.svg | image_class = skin-invert-image | width = 150 | alt = | chirality = Racemic mixture | caption = | image2 = Sodium thiopental ball and stick model.png | image_class2 = bg-transparent | width2 = | alt2 =

| pronounce = | tradename = Pentothal, others | Drugs.com = {{drugs.com|monograph|thiopental-sodium}} | MedlinePlus = | DailyMedID =  | pregnancy_AU = D | pregnancy_AU_comment = | pregnancy_category = | routes_of_administration = Intravenous, by mouth, rectal | class = Barbiturate | ATC_prefix = N01 | ATC_suffix = AF03 | ATC_supplemental = {{ATC|N05|CA19}}

| legal_AU = S4 | legal_AU_comment = | legal_BR = B1 | legal_BR_comment = <ref>{{cite web |author=Anvisa |author-link=Brazilian Health Regulatory Agency |date=2023-03-31 |title=RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial |trans-title=Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control|url=https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |url-status=live |archive-url=https://web.archive.org/web/20230803143925/https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |archive-date=2023-08-03 |access-date=2023-08-16 |publisher=Diário Oficial da União |language=pt-BR |publication-date=2023-04-04}}</ref> | legal_CA = Schedule IV | legal_CA_comment = | legal_DE =  | legal_DE_comment = | legal_NZ =  | legal_NZ_comment = | legal_UK = Class B | legal_UK_comment = | legal_US = Schedule III | legal_US_comment = <ref name="Pentothal FDA label">{{cite web | title=Pentothal | website=DailyMed | url=https://dailymed.nlm.nih.gov/dailymed/archives/fdaDrugInfo.cfm?archiveid=48745 | access-date=15 September 2025}}</ref> | legal_EU = | legal_EU_comment = | legal_UN =  | legal_UN_comment = | legal_status =

| bioavailability = | protein_bound = 80% | metabolism = Liver | metabolites = Pentobarbital, others | onset = 30–45 seconds | elimination_half-life = 5.5<ref>{{cite journal | vauthors = Russo H, Brès J, Duboin MP, Roquefeuil B | title = Pharmacokinetics of thiopental after single and multiple intravenous doses in critical care patients | journal = European Journal of Clinical Pharmacology | volume = 49 | issue = 1–2 | pages = 127–37 | year = 1995 | pmid = 8751034 | doi = 10.1007/BF00192371 | s2cid = 24285007 }}</ref>–26 hours<ref name="Pharmacokinetics and plasma binding">{{cite journal | vauthors = Morgan DJ, Blackman GL, Paull JD, Wolf LJ | title = Pharmacokinetics and plasma binding of thiopental. II: Studies at cesarean section | journal = Anesthesiology | volume = 54 | issue = 6 | pages = 474–80 | date = June 1981 | pmid = 7235275 | doi = 10.1097/00000542-198106000-00006 | doi-access = free }}</ref> | duration_of_action = 5–10 minutes | excretion =

| IUPAC_name = sodium 5-ethyl-5-pentan-2-yl-2-sulfanylidene-1,3-diazinane-4,6-dione | C = 11 | H = 17 | N = 2 | Na = 1 | O = 2 | S = 1 | SMILES = [Na+].O=C1NC(=S)/N=C(/[O-])C1(C(C)CCC)CC | StdInChI = 1S/C11H18N2O2S.Na/c1-4-6-7(3)11(5-2)8(14)12-10(16)13-9(11)15;/h7H,4-6H2,1-3H3,(H2,12,13,14,15,16);/q;+1/p-1 | StdInChIKey = AWLILQARPMWUHA-UHFFFAOYSA-M | density = | density_notes = | melting_point = | melting_high = | melting_notes = | boiling_point = | boiling_notes = | solubility = | sol_units = | specific_rotation = }}

thumb|Pentothal vintage package

'''Sodium thiopental''', also known as '''thiopental sodium''' or '''thiopentone''' and sold under the brand name '''Pentothal''', is a rapid-onset short-acting barbiturate general anesthetic. It is the thiobarbiturate analog of pentobarbital, and an analog of thiobarbital. Sodium thiopental is a therapeutic alternative on the World Health Organization's List of Essential Medicines.<ref name="WHO24th">{{cite book | vauthors = ((World Health Organization)) | title = The selection and use of essential medicines, 2025: WHO Model List of Essential Medicines, 24th list | year = 2025 | hdl = 10665/382243 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | hdl-access=free }}</ref> It was the first of three drugs administered during most lethal injections in the United States until the US division of Hospira objected and stopped manufacturing the drug for this purpose in 2011, and the European Union additionally banned the export of the drug for this purpose.<ref>{{cite news|url=https://www.spiegel.de/international/europe/death-penalty-opposition-eu-set-to-ban-export-of-drug-used-in-us-executions-a-803238.html|title=Death Penalty Opposition: EU Set to Ban Export of Drug Used in US Executions|publisher=Spiegel Online International|access-date=23 January 2014}}</ref> Although thiopental abuse carries a dependency risk, its recreational use is rare.<ref>{{cite book | vauthors = Bryson EO | chapter = The Abuse of Agents Used to Induce or Maintain General Anesthesia: Intravenous Hypnotics and the Halogenated Hydrocarbons | veditors = Kaye AD, Vadivelu N, Urman RD | title = Substance abuse: inpatient and outpatient management for every clinician |isbn=978-1-4939-1951-2 | doi = 10.1007/978-1-4939-1951-2_10 |location=New York | publisher = Springer |oclc=897466425|date = December 2014 | page = 115 }}</ref>

Sodium thiopental is well-known in popular culture, especially under the name "sodium pentothal," as a "truth serum," although its efficacy in this role is questioned.<ref>{{Cite news |date=2013-10-03 |title=Can a drug make you tell the truth? |url=https://www.bbc.com/news/magazine-24371140 |access-date=2024-05-19 |work=BBC News }}</ref><ref>{{Cite web |last=Orwig |first=Jessica |title='Truth serum' drugs do exist. Here's how medicines like sodium pentothal and scopolamine can manipulate the brain. |url=https://www.businessinsider.com/is-there-such-a-thing-as-truth-serum-2014-10 |access-date=2024-05-19 |website=Business Insider }}</ref>

==Uses==

===Anesthesia=== Sodium thiopental is an ultra-short-acting barbiturate and has been used commonly in the induction phase of general anesthesia. Its use has been largely replaced with that of propofol, but may retain some popularity as an induction agent for rapid-sequence induction and intubation, such as in obstetrics.<ref>{{cite journal | vauthors = Çakırtekin V, Yıldırım A, Bakan N, Çelebi N, Bozkurt Ö | title = Comparison of the Effects of Thiopental Sodium and Propofol on Haemodynamics, Awareness and Newborns During Caesarean Section Under General Anaesthesia | journal = Turkish Journal of Anaesthesiology and Reanimation | volume = 43 | issue = 2 | pages = 106–112 | date = April 2015 | pmid = 27366476 | pmc = 4917150 | doi = 10.5152/TJAR.2014.75547 }}</ref> Following intravenous injection, the drug rapidly reaches the brain and causes unconsciousness within 30–45 seconds. At one minute, the drug attains a peak concentration of about 60% of the total dose in the brain. Thereafter, the drug distributes to the rest of the body, and in about 5–10 minutes the concentration in the brain is low enough that consciousness returns.

A normal dose of sodium thiopental (usually 4-6 mg/kg) given to a pregnant woman for operative delivery (caesarean section) rapidly makes her unconscious, but the baby in her uterus remains conscious. However, larger or repeated doses can depress the baby's consciousness.<ref name="GleasonJuul2011">{{cite book|vauthors=Gleason CA, Juul SE|title=Avery's Diseases of the Newborn|date=12 August 2011|publisher=Elsevier Health Sciences|isbn=978-1-4557-2714-8|page=169|url=http://www.us.elsevierhealth.com/averys-diseases-of-the-newborn-9781437701340.html|access-date=13 August 2016|archive-date=26 November 2022|archive-url=https://web.archive.org/web/20221126100518/https://www.us.elsevierhealth.com/averys-diseases-of-the-newborn-9781437701340.html|url-status=dead}}</ref>

Sodium thiopental is not used to maintain anesthesia in surgical procedures because, in infusion, it displays zero-order elimination pharmacokinetics, leading to a long period before consciousness is regained. Instead, anesthesia is usually maintained with an inhaled anesthetic (gas) agent. Inhaled anesthetics are eliminated relatively quickly, so stopping the inhaled anesthetic allows rapid return of consciousness. Sodium thiopental would have to be given in large amounts to maintain unconsciousness during anaesthesia due to its rapid redistribution throughout the body (as it has a high volume of distribution). Since its half-life of 5.5 to 26 hours is quite long, consciousness would take a long time to return.<ref name="Pharmacokinetics and plasma binding">{{cite journal | vauthors = Morgan DJ, Blackman GL, Paull JD, Wolf LJ | title = Pharmacokinetics and plasma binding of thiopental. II: Studies at cesarean section | journal = Anesthesiology | volume = 54 | issue = 6 | pages = 474–80 | date = June 1981 | pmid = 7235275 | doi = 10.1097/00000542-198106000-00006 | doi-access = free }}</ref>

In veterinary medicine, sodium thiopental is used to induce anesthesia in animals. Since it is redistributed to fat, certain lean breeds of dogs such as sighthounds have prolonged recoveries from sodium thiopental due to their lack of body fat and their lean body mass. Conversely, obese animals recover rapidly, but it takes much longer for the drug to be entirely removed (metabolized) from their bodies. Sodium thiopental is always administered intravenously, as it can be fairly irritating to tissue and is a vesicant; severe tissue necrosis and sloughing can occur if it is injected incorrectly into the tissue around a vein.<ref>{{cite journal | vauthors = Shibata Y, Yokooji T, Itamura R, Sagara Y, Taogoshi T, Ogawa K, Tanaka M, Hide M, Kihira K, Matsuo H | title = Injury due to extravasation of thiopental and propofol: Risks/effects of local cooling/warming in rats | journal = Biochemistry and Biophysics Reports | volume = 8 | pages = 207–211 | date = December 2016 | pmid = 28955958 | pmc = 5613958 | doi = 10.1016/j.bbrep.2016.09.005 | url = }}</ref>

===Medically-induced coma=== In addition to anesthesia induction, sodium thiopental was historically used to induce medical comas.<ref>{{cite web |url= http://www.trauma.org/archive/anaesthesia/barbcoma.html |title=TRAUMA.ORG: Critical Care: Barbiturate Coma| vauthors = Takeko T |website=trauma.org|access-date=18 August 2016|archive-url= https://web.archive.org/web/20160819000601/http://www.trauma.org/archive/anaesthesia/barbcoma.html |archive-date=19 August 2016}}</ref> It has now been superseded by drugs such as propofol because their effects wear off more quickly than thiopental. Patients with brain swelling, causing elevation of intracranial pressure, either secondary to trauma or following surgery, may benefit from this drug. Sodium thiopental, and the barbiturate class of drugs, decrease neuronal activity thereby decreasing cerebral metabolic rate of oxygen consumption (CMRO2), thus decreasing the cerebrovascular response to carbon dioxide, which in turn decreases intracranial pressure. Patients with refractory elevated intracranial pressure (RICH) due to traumatic brain injury (TBI) may have improved long term outcome when barbiturate coma is added to their neurointensive care treatment.<ref name="pmid29058090">{{cite journal | vauthors = Abraham P, Rennert RC, Gabel BC, Sack JA, Karanjia N, Warnke P, Chen CC | title = ICP management in patients suffering from traumatic brain injury: a systematic review of randomized controlled trials | journal = Acta Neurochirurgica | volume = 159 | issue = 12 | pages = 2279–2287 | date = December 2017 | pmid = 29058090 | doi = 10.1007/s00701-017-3363-1 | s2cid = 3013248 }}</ref> Reportedly, thiopental has been shown to be superior to pentobarbital in reducing intracranial pressure.<ref name="pmid23235573">{{cite journal | vauthors = Roberts I, Sydenham E | title = Barbiturates for acute traumatic brain injury | journal = The Cochrane Database of Systematic Reviews | volume = 2012 | article-number = CD000033 | date = December 2012 | issue = 12 | pmid = 23235573 | pmc = 7061245 | doi = 10.1002/14651858.CD000033.pub2 }}</ref> This phenomenon is also called an inverse steal or Robin Hood effect as cerebral perfusion to all parts of the brain is reduced (due to the decreased cerebrovascular response to carbon dioxide) allowing optimal perfusion to ischaemic areas of the brain which have higher metabolic demands, since vessels supplying ischaemic areas of the brain would already be maximally dilated because of the metabolic demand.<ref>{{cite web |vauthors=Trickey D |title=Anesthetic Management of Head-injured Patients |url=http://www.amcresidents.com/lectures/Dr_Trickey/Physiology_of_CBF_and_CSF.htm |access-date=2020-10-13 |website=www.amcresidents.com |archive-date=2020-10-18 |archive-url=https://web.archive.org/web/20201018124821/http://www.amcresidents.com/lectures/Dr_Trickey/Physiology_of_CBF_and_CSF.htm }}</ref>

===Euthanasia=== Sodium thiopental is used intravenously for the purposes of euthanasia. In both Belgium and the Netherlands, where active euthanasia is allowed by law, the standard protocol recommends sodium thiopental as the ideal agent to induce coma, followed by pancuronium bromide to paralyze muscles and stop breathing.<ref name=euthanasics>{{cite web |url=http://wweek.com/html/euthanasics.html |title=Administration and Compounding of Euthanasic Agents |access-date=2008-07-18 |author=Royal Dutch Society for the Advancement of Pharmacy |publisher=The Hague |year=1994 |archive-url=https://web.archive.org/web/20080821133010/http://www.wweek.com/html/euthanasics.html |archive-date=2008-08-21 }}</ref>

Intravenous administration is the most reliable and rapid way to accomplish euthanasia. Death is quick. A coma is first induced by intravenous administration of 20 mg/kg thiopental sodium (Nesdonal) in a small volume (10 mL physiological saline). Then, a triple dose of a non-depolarizing neuromuscular blocking drug is given, such as 20 mg pancuronium bromide (Pavulon) or 20 mg vecuronium bromide (Norcuron). The paralytic should be given intravenously to ensure optimal bioavailability but pancuronium bromide may be administered intramuscularly at an increased dosage level of 40 mg.<ref name=euthanasics/>

===Lethal injection=== {{Further|Lethal injection}}

Along with pancuronium bromide and potassium chloride, thiopental is used in 34 US states to execute prisoners by lethal injection. A large dose is given to ensure rapid loss of consciousness. Although death usually occurs within ten minutes of the beginning of the injection process, some have been known to take longer.<ref name="OHIO">{{cite news |date= December 2001 |url= https://nypost.com/2009/12/08/ohio-executes-inmate-with-1-drug-lethal-injection/ |title= Ohio executes inmate with 1-drug lethal injection |agency= Associated Press |access-date= 2009-12-08 }}</ref>

In December 2009, Ohio became the first state in the US to use a single dose of sodium thiopental for an execution, following the failed use of the standard three-drug cocktail during a prior execution, due to inability to locate suitable veins. Kenneth Biros was executed using the single-drug method.<ref>{{cite news |url= https://www.cbsnews.com/news/kenneth-biros-execution-ohio-man-first-to-die-under-1-drug-thiopental-sodium-method/ |title= Kenneth Biros Execution: Ohio Man First to Die Under 1-Drug Thiopental Sodium Method | vauthors = Martinez E |date= 8 December 2009 |work= CBS News}}</ref>

Washington became the second state in the US to use the single-dose sodium thiopental injections for executions. In September 2010, the execution of Cal Coburn Brown was the first in the state to use a single-dose, single-drug injection. His death was pronounced approximately one and a half minutes after the intravenous administration of five grams of the drug.<ref>{{cite news |url= http://seattletimes.nwsource.com/html/localnews/2012856652_execution10m.html |title= Killer on death row 16-1/2 years is executed |work= The Seattle Times |date= 10 September 2010 | vauthors = Sullivan J }}</ref>

After its use for the execution of Jeffrey Landrigan in the US, the United Kingdom introduced a ban on the export of sodium thiopental in December 2010,<ref>{{cite web|url=https://www.bbc.co.uk/news/uk-12263460|title=Drug sold in UK to be used for execution in Georgia|website=bbc.co.uk|publisher=BBC News|date=24 January 2011|access-date=18 August 2016}}</ref> after it was established that no European supplies to the US were being used for any other purpose.<ref>{{cite web|url=https://www.bbc.co.uk/news/uk-11865881|title=US lethal injection drug faces UK export restrictions|website=bbc.co.uk|publisher=BBC News| vauthors = Casciani D |date=29 November 2010|access-date=18 August 2016}}</ref> The restrictions were based on "the European Union Torture Regulation (including licensing of drugs used in execution by lethal injection)".<ref>{{cite web|url=https://www.gov.uk/controls-on-torture-goods|title=Controls on torture goods - Detailed guidance - GOV.UK|website=gov.uk|access-date=18 August 2016}}</ref> From 21 December 2011, the EU extended trade restrictions to prevent the export of certain medicinal products for capital punishment, stating that "the Union disapproves of capital punishment in all circumstances and works towards its universal abolition".<ref>{{cite web| url = https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2011:338:0031:0034:EN:PDF| title = EU Council Regulation (EU) No 1352/2011}}</ref>

===Truth serum=== {{Further|Truth serum}} Thiopental is still used in some places as a truth serum to weaken the resolve of a subject and make the individual more compliant to pressure.<ref name="SMH_truth_serum">{{cite news|url=https://www.smh.com.au/world/truth-serum-used-on-serial-child-killers-20070113-gdp8d6.html|newspaper=Sydney Morning Herald|title=Truth serum used on 'serial child killers'|date=January 12, 2007|agency=Reuters}}</ref> Barbiturates decrease both higher cortical brain function and inhibition. It is thought that because lying is a more involved process than telling the truth, suppression of the higher cortical functions may lead to the uncovering of the truth. The drug tends to make subjects verbose and cooperative with interrogators; however, the reliability of confessions made under thiopental is questionable.<ref>{{cite book | vauthors = Bannon A, Stevens SD |title=The Howdunit Book of Poisons (Howdunit) |publisher=Writers Digest Books |location=Cincinnati |year=2007 |isbn=978-1-58297-456-9}}</ref>

===Psychiatry=== Psychiatrists have used thiopental to desensitize patients with phobias<ref>{{cite journal | vauthors = Pearlman T | title = Behavioral desensitization of phobic anxiety using thiopental sodium | journal = The American Journal of Psychiatry | volume = 137 | issue = 12 | pages = 1580–2 | date = December 1980 | pmid = 6108082 | doi = 10.1176/ajp.137.12.1580 | publisher = American Psychiatric Association }}</ref> and to "facilitate the recall of painful repressed memories."<ref>{{cite magazine |url= http://content.time.com/time/magazine/article/0,9171,863001,00.html |title= Drugged Future? |date= February 24, 1958 |magazine= TIME |access-date= 16 June 2019 |archive-date= 10 September 2023 |archive-url= https://web.archive.org/web/20230910024423/https://content.time.com/time/magazine/article/0,9171,863001,00.html |url-status= dead }}</ref> One psychiatrist who worked with thiopental is Jan Bastiaans, who used this procedure to help relieve trauma in surviving victims of the Holocaust.<ref>{{cite journal |url= http://www.maps.org/news-letters/v08n1/08118sne.html |title= The LSD Therapy Career of Jan Bastiaans, M.D | vauthors = Snelders S |journal= Newsletter of the Multidisciplinary Association for Psychedelic Studies |publisher= Multidisciplinary Association for Psychedelic Studies |volume= 8 |issue= 1 |year= 1998 |pages= 18–20}}</ref> Another notable psychiatrist using thiopental for the first time in the 1960s in psychoanalytic therapy setting - in a somewhat similar way to psycholytic psychotherapy - was the Hungarian-Australian psychiatrist Imre Zádor.<ref>{{Cite book |last=Zádor |first=Imre |title=Lélekgyógyítás tengereken túl: Egy pszichiáter visszaemlékezései |publisher=AduPrint |year=1998 |isbn=963-85647-9-2 |location=Budapest |pages=74, 188 |language=hu |trans-title=Soul Healing Overseas: The Memoirs of a Psychiatrist}}</ref> He administered thiopental to psychotherapy patients to reduce transferential resistance in cases of anorexia nervosa as well as to resolve unconscious blockages in other cases.

==Mechanism of action== {{Main|Barbiturate}}

Sodium thiopental is a member of the barbiturate class of drugs, which are relatively non-selective compounds that bind to an entire superfamily of ligand-gated ion channels, of which the GABAA receptor channel is one of several representatives. This superfamily of ion channels includes the neuronal nicotinic acetylcholine receptor (nAChR), the 5-HT3 receptor, the glycine receptor and others. Surprisingly, while GABAA receptor currents are increased by barbiturates (and other general anesthetics), ligand-gated ion channels that are predominantly permeable for cationic ions are blocked by these compounds. For example, neuronal nAChR are blocked by clinically relevant anesthetic concentrations of both sodium thiopental and pentobarbital.<ref name="Weber_nAChR_anaesthetics">{{cite journal | vauthors = Weber M, Motin L, Gaul S, Beker F, Fink RH, Adams DJ | title = Intravenous anaesthetics inhibit nicotinic acetylcholine receptor-mediated currents and Ca2+ transients in rat intracardiac ganglion neurons | journal = British Journal of Pharmacology | volume = 144 | issue = 1 | pages = 98–107 | date = January 2005 | pmid = 15644873 | pmc = 1575970 | doi = 10.1038/sj.bjp.0705942 }}</ref> Such findings implicate (non-GABAergic) ligand-gated ion channels, e.g. the neuronal nAChR, in mediating some of the (side) effects of barbiturates.<ref name="Franks_Lieb_general_anaesthetics">{{cite journal | vauthors = Franks NP, Lieb WR | title = Which molecular targets are most relevant to general anaesthesia? | journal = Toxicology Letters | volume = 100-101 | issue = 1–2 | pages = 1–8 | date = November 1998 | pmid = 10049127 | doi = 10.1016/S0378-4274(98)00158-1 }}</ref> The GABAA receptor is an inhibitory channel that decreases neuronal activity, and barbiturates enhance the inhibitory action of the GABAA receptor.<ref>{{cite web |url=http://www.healthsystem.virginia.edu/internet/ccm/Anesth/aneshome.cfm |title=Anesthesia and Analgesia |access-date=2007-08-05 |publisher=University of Virginia School of Medicine |archive-date=2007-05-18 |archive-url=https://web.archive.org/web/20070518031409/http://www.healthsystem.virginia.edu/internet/ccm/Anesth/aneshome.cfm }}</ref>

==Controversies== Following a shortage that led a court to delay an execution in California, a company spokesman for Hospira, the sole American manufacturer of the drug, objected to the use of thiopental in lethal injection. "Hospira manufactures this product because it improves or saves lives, and the company markets it solely for use as indicated on the product labeling. The drug is not indicated for capital punishment and Hospira does not support its use in this procedure."<ref>{{cite news | vauthors = Pilkington E |date=2010-09-28 |title=US executions delayed by shortage of death penalty drug |work=Guardian |url=http://www.theguardian.com/world/2010/sep/28/us-executions-delayed-drug-shortage |access-date=2022-06-18}}</ref> On January 21, 2011, the company announced that it would stop production of sodium thiopental from its plant in Italy, because it could not provide Italian authorities with guarantees that exported doses would not be used in executions. According to a company spokesperson, Italy was the only viable place where it could produce the drug, leaving the US without a supplier.<ref>{{cite news | vauthors = Welsh-Huggins A |date=January 21, 2011 |title=Key death penalty drug discontinued by U.S. maker |work=NBC News |url=http://www.nbcnews.com/health/health-news/key-death-penalty-drug-discontinued-u-s-maker-flna1C9467323 |access-date=2022-06-18}}</ref>

In October 2015 the US Food and Drug Administration (FDA) confiscated an overseas shipment of thiopental destined for the states of Arizona and Texas. The FDA said in a statement, "Courts have concluded that sodium thiopental for the injection in humans is an unapproved drug and may not be imported into the country".<ref>{{cite magazine |title=The FDA Confiscated A Supply Of Execution Drugs Texas Is Thought To Have Imported Illegally |url=https://www.texasmonthly.com/the-daily-post/the-fda-confiscated-a-supply-of-execution-drugs-texas-is-thought-to-have-imported-illegally/ | vauthors = Solomon D |magazine=Texas Monthly |date=October 27, 2015 |access-date=March 10, 2021}}</ref>

==Metabolism== Thiopental rapidly and easily crosses the blood–brain barrier as it is a lipophilic molecule. As with all lipid-soluble anaesthetic drugs, the short duration of action of sodium thiopental is due almost entirely to its redistribution away from central circulation into muscle and fatty tissue, due to its very high lipid–water partition coefficient (approximately 10), leading to sequestration in fatty tissue. Once redistributed, the free fraction in the blood is metabolized in the liver by zero-order kinetics. Sodium thiopental is mainly metabolized to pentobarbital,<ref>{{cite journal | vauthors = Winters WD, Spector E, Wallach DP, Shideman FE | title = Metabolism of thiopental-S35 and thiopental-2-C14 by a rat liver mince and identification of pentobarbital as a major metabolite | journal = The Journal of Pharmacology and Experimental Therapeutics | volume = 114 | issue = 3 | pages = 343–57 | date = July 1955 | pmid = 13243246 | url = http://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=13243246 }}{{dead link|date=June 2016|bot=medic}}{{cbignore|bot=medic}}</ref> 5-ethyl-5-(1'-methyl-3'-hydroxybutyl)-2-thiobarbituric acid, and 5-ethyl-5-(1'-methyl-3'-carboxypropyl)-2-thiobarbituric acid.<ref>{{cite journal | vauthors = Bory C, Chantin C, Boulieu R, Cotte J, Berthier JC, Fraisse D, Bobenrieth MJ | title = [Use of thiopental in man. Determination of this drug and its metabolites in plasma and urine by liquid phase chromatography and mass spectrometry] | language = fr | journal = Comptes Rendus de l'Académie des Sciences, Série III | volume = 303 | issue = 1 | pages = 7–12 | year = 1986 | pmid = 3093002 }}</ref>

==Dosage== The usual dose range for induction of anesthesia using thiopental is from 3 to 6 mg/kg; however, there are many factors that can alter this. Premedication with sedatives such as benzodiazepines or clonidine will reduce requirements due to drug synergy, as do specific disease states and other patient factors. Among patient factors are: age, sex, and lean body mass.<ref>{{cite journal | vauthors = Avram M, Krejcie T, Henthorn T | title = [The relationship of age to the pharmacokinetics of early drug distribution: the concurrent disposition of thiopental and indocyanine green.] | language = en | journal = Anesthesiology | volume = 72 | issue = 3 | pages = 403–411 | year = 1990 | doi = 10.1097/00000542-199003000-00002 | pmid = 2310019 | doi-access = free }}</ref> Specific disease conditions that can alter the dose requirements of thiopentone and for that matter any other intravenous anaesthetic are: hypovolemia, burns, azotemia, liver failure, hypoproteinemia, etc.<ref>{{cite web|url=https://www.rxlist.com/pentothal-drug.htm#description|title=PENTOTHAL|website=RXList|publisher=WebMD|date=15 November 2021|access-date=18 June 2023}}</ref>

==Contraindications== Thiopental should be used with caution in cases of liver disease, Addison's disease, myxedema, severe heart disease, severe hypotension, a severe breathing disorder, or a family history of porphyria.<ref>{{cite web|url=http://www.emedicinehealth.com/drug-thiopental/article_em.htm|title=Pentothal (thiopental)|date=12 April 2009|publisher=eMedicineHealth|access-date=15 October 2010|archive-date=18 January 2015|archive-url=https://web.archive.org/web/20150118060951/http://www.emedicinehealth.com/drug-thiopental/article_em.htm}}</ref><ref>{{cite journal | vauthors = James MF, Hift RJ | title = Porphyrias | journal = British Journal of Anaesthesia | volume = 85 | issue = 1 | pages = 143–53 | date = July 2000 | pmid = 10928003 | doi = 10.1093/bja/85.1.143 | url = https://academic.oup.com/bja/article/85/1/143/263924 | doi-access = free }}</ref>

Co-administration of pentoxifylline and thiopental causes death by acute pulmonary edema in rats. This pulmonary edema was not mediated by cardiac failure or by pulmonary hypertension but was due to increased pulmonary vascular permeability.<ref>{{cite journal | vauthors = Pereda J, Gómez-Cambronero L, Alberola A, Fabregat G, Cerdá M, Escobar J, Sabater L, García-de-la-Asunción J, García-de-la-Asuneión J, Viña J, Sastre J | title = Co-administration of pentoxifylline and thiopental causes death by acute pulmonary oedema in rats | journal = British Journal of Pharmacology | volume = 149 | issue = 4 | pages = 450–5 | date = October 2006 | pmid = 16953192 | pmc = 1978439 | doi = 10.1038/sj.bjp.0706871 }}</ref>

==History== Sodium thiopental was discovered in the early 1930s by Ernest H. Volwiler and Donalee L. Tabern, working for Abbott Laboratories. It was first used in human beings on March 8, 1934, by Dr. Ralph M. Waters<ref>{{cite web |url= http://www.anesthesia.wisc.edu/AHA/Calendar/March.html |title= This Month in Anesthesia History: March |publisher= Anesthesia History Association |archive-url= https://web.archive.org/web/20110501085226/http://www.anesthesia.wisc.edu/AHA/Calendar/March.html |archive-date= 2011-05-01 }}</ref> in an investigation of its properties, which were short-term anesthesia and surprisingly little analgesia.<ref>{{cite journal| vauthors = Steinhaus JE |url= http://www.asahq.org/~/media/For%20Members/Publications/Periodicals/ASA%20Newsletter/NL%20Archives/2001/09%20Sept%2001.ashx |title=The Investigator and His 'Uncompromising Scientific Honesty'|publisher=American Society of Anesthesiologists|journal=ASA Newsletter|date=September 2001|volume=65|issue=9|pages=7–9|archive-url=https://web.archive.org/web/20110513131342/http://www.asahq.org/~/media/For%20Members/Publications/Periodicals/ASA%20Newsletter/NL%20Archives/2001/09%20Sept%2001.ashx|archive-date=2011-05-13}}</ref> Three months later,<ref>{{cite journal | vauthors = Lundy JS | title = From this point in time: some memories of my part in the history of anesthesia | journal = The Journal of the American Association of Nurse Anesthetists | volume = 34 | issue = 2 | pages = 95–102 | date = April 1966 | pmid = 5175948 | url = http://www.aana.com/Resources.aspx?id=1811 | publisher = American Association of Nurse Anesthetists | archive-url = https://web.archive.org/web/20110501075555/http://www.aana.com/Resources.aspx?id=1811 | archive-date = 2011-05-01 }}</ref> Dr. John S. Lundy started a clinical trial of thiopental at the Mayo Clinic at the request of Abbott.<ref>{{cite book|url=http://www.aana.com/Resources.aspx?id=1730|title=History of Anesthesia with Emphasis on the Nurse Specialist| vauthors = Thatcher VS |year=1984 |orig-date=1953|publisher=J.B. Lippincott |chapter=Chapter 7: Illegal or Legal? |chapter-url= http://www.aana.com/uploadedFiles/Resources/Archives_-_Library/Historical_Resources/Thatcher/0008CHP7.PDF |isbn=0-8240-6525-5 |archive-url= https://web.archive.org/web/20110501075551/http://www.aana.com/Resources.aspx?id=1730 |archive-date=2011-05-01}}</ref> Abbott continued to make the drug until 2004, when it spun off its hospital-products division as Hospira.

Thiopental is famously associated with a number of anesthetic deaths in victims of the attack on Pearl Harbor. These deaths, relatively soon after the drug's introduction, were said to be due to excessive doses given to shocked trauma patients. However, evidence available through the freedom of information legislation<ref name="pmid7547061">{{cite journal | vauthors = Bennetts FE | title = Thiopentone anaesthesia at Pearl Harbor | journal = British Journal of Anaesthesia | volume = 75 | issue = 3 | pages = 366–8 | date = September 1995 | pmid = 7547061 | doi = 10.1093/bja/75.3.366 | doi-access = free }}</ref> suggested that the story was exaggerated. Of the 344 wounded that were admitted to the Tripler Army Hospital, only 13 did not survive, and it is unlikely that thiopentone overdose was responsible for more than a few of them.

== References == {{Reflist}}

== External links == {{Commons}} * Vassallo, Susi, M.D. "[https://ir.lawnet.fordham.edu/ulj/vol35/iss4/10 Thiopental in Lethal Injection]" ([https://web.archive.org/web/20160320215157/https://www.law.berkeley.edu/clinics/dpclinic/LethalInjection/LI/documents/articles/journal/vassallo.pdf Archive]). ''Fordham Urban Law Journal''. Vol. 35, issue 4. June 18, 2008. pp. 957–968.

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