Sodium thiopental

Sodium thiopental
Clinical data
Trade names	Pentothal, others
Other names	Truth serum, thiopentone, thiopental
AHFS/Drugs.com	Monograph
Pregnancy; category	AU: D;
Routes of; administration	Intravenous, by mouth, rectal
Drug class	Barbiturate
ATC code	N01AF03 (WHO) N05CA19 (WHO);
Legal status
Legal status	AU: S4 (Prescription only); BR: Class B1 (Psychoactive drugs); CA: Schedule IV; UK: Class B; US: Schedule III;
Pharmacokinetic data
Protein binding	80%
Metabolism	Liver
Metabolites	Pentobarbital, others
Onset of action	30–45 seconds
Elimination half-life	5.5–26 hours
Duration of action	5–10 minutes
Identifiers
	IUPAC name sodium 5-ethyl-5-pentan-2-yl-2-sulfanylidene-1,3-diazinane-4,6-dione;
CAS Number	71-73-8; 76-75-5;
PubChem CID	3000714;
DrugBank	DB00599;
ChemSpider	2272257;
UNII	49Y44QZL70;
KEGG	D00714;
ChEBI	CHEBI:9561;
ChEMBL	ChEMBL738;
CompTox Dashboard (EPA)	DTXSID1021744 ;
ECHA InfoCard	100.000.694
Chemical and physical data
Formula	C11H17N2NaO2S
Molar mass	264.32 g·mol−1
3D model (JSmol)	Interactive image;
Chirality	Racemic mixture
	SMILES [Na+].O=C1NC(=S)/N=C(/[O-])C1(C(C)CCC)CC;
	InChI InChI=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; Key:AWLILQARPMWUHA-UHFFFAOYSA-M;

Sodium thiopental, also known as 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.^[5] 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 in 2011, and the European Union banned the export of the drug for this purpose.^[6] Although thiopental abuse carries a dependency risk, its recreational use is rare.^[7]

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.^[8]^[9]

^ Anvisa (31 March 2023). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 4 April 2023). Archived from the original on 3 August 2023. Retrieved 16 August 2023.
^ "Pentothal". DailyMed. Retrieved 15 September 2025.
^ Russo H, Brès J, Duboin MP, Roquefeuil B (1995). "Pharmacokinetics of thiopental after single and multiple intravenous doses in critical care patients". European Journal of Clinical Pharmacology. 49 (1–2): 127–37. doi:10.1007/BF00192371. PMID 8751034. S2CID 24285007.
^ Morgan DJ, Blackman GL, Paull JD, Wolf LJ (June 1981). "Pharmacokinetics and plasma binding of thiopental. II: Studies at cesarean section". Anesthesiology. 54 (6): 474–80. doi:10.1097/00000542-198106000-00006. PMID 7235275.
^ World Health Organization (2025). The selection and use of essential medicines, 2025: WHO Model List of Essential Medicines, 24th list. Geneva: World Health Organization. hdl:10665/382243.
^ "Death Penalty Opposition: EU Set to Ban Export of Drug Used in US Executions". Spiegel Online International. Retrieved 23 January 2014.
^ Bryson EO (December 2014). "The Abuse of Agents Used to Induce or Maintain General Anesthesia: Intravenous Hypnotics and the Halogenated Hydrocarbons". In Kaye AD, Vadivelu N, Urman RD (eds.). Substance abuse: inpatient and outpatient management for every clinician. New York: Springer. p. 115. doi:10.1007/978-1-4939-1951-2_10. ISBN 978-1493919512. OCLC 897466425.
^ "Can a drug make you tell the truth?". BBC News. 3 October 2013. Retrieved 19 May 2024.
^ Orwig J. "'Truth serum' drugs do exist. Here's how medicines like sodium pentothal and scopolamine can manipulate the brain". Business Insider. Retrieved 19 May 2024.

[1] Anvisa (31 March 2023). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 4 April 2023). Archived from the original on 3 August 2023. Retrieved 16 August 2023.

[Pentothal_FDA_label-2] "Pentothal". DailyMed. Retrieved 15 September 2025.

[3] Russo H, Brès J, Duboin MP, Roquefeuil B (1995). "Pharmacokinetics of thiopental after single and multiple intravenous doses in critical care patients". European Journal of Clinical Pharmacology. 49 (1–2): 127–37. doi:10.1007/BF00192371. PMID 8751034. S2CID 24285007.

[Pharmacokinetics_and_plasma_binding-4] Morgan DJ, Blackman GL, Paull JD, Wolf LJ (June 1981). "Pharmacokinetics and plasma binding of thiopental. II: Studies at cesarean section". Anesthesiology. 54 (6): 474–80. doi:10.1097/00000542-198106000-00006. PMID 7235275.

[WHO24th-5] World Health Organization (2025). The selection and use of essential medicines, 2025: WHO Model List of Essential Medicines, 24th list. Geneva: World Health Organization. hdl:10665/382243.

[6] "Death Penalty Opposition: EU Set to Ban Export of Drug Used in US Executions". Spiegel Online International. Retrieved 23 January 2014.

[7] Bryson EO (December 2014). "The Abuse of Agents Used to Induce or Maintain General Anesthesia: Intravenous Hypnotics and the Halogenated Hydrocarbons". In Kaye AD, Vadivelu N, Urman RD (eds.). Substance abuse: inpatient and outpatient management for every clinician. New York: Springer. p. 115. doi:10.1007/978-1-4939-1951-2_10. ISBN 978-1493919512. OCLC 897466425.

[8] "Can a drug make you tell the truth?". BBC News. 3 October 2013. Retrieved 19 May 2024.

[9] Orwig J. "'Truth serum' drugs do exist. Here's how medicines like sodium pentothal and scopolamine can manipulate the brain". Business Insider. Retrieved 19 May 2024.

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