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WARNINGOVERDOSE, COMBINATIONS, & WITHDRAWAL CAN BE FATAL
High doses alone or ordinary doses in combination with other depressants can fatally stop breathing. After prolonged dependency, stopping suddenly can cause seizures, delirium, or death.
Thiopental
Thiopental is an ultrashort-acting barbiturate of the thiobarbituric acid class,1 primarily used in clinical settings for the induction of general anesthesia, management of convulsions, and reduction of intracranial pressure.citation needed Administered intravenously, it produces rapid-onset hypnosis and anesthesia but notably lacks analgesic properties,1 small doses may actually lower the pain threshold.citation needed It is considered habit-forming and is also employed in medically induced comas.2
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Standard clinical protocols for anesthesia induction employ doses in the range of 3-6 mg/kg, while barbiturate coma induction may require approximately 20 mg/kg. These figures are derived from medical anesthetic applications; reliable data on non-medical dosing does not exist.
Duration
Subjective Effects
Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.
The experience is defined by an extremely rapid loss of consciousness, with hypnosis setting in within roughly 30 to 40 seconds of intravenous injection and no excitation phase preceding it. The state produced is one of anesthesia and hypnosis rather than pain relief; small doses can actually lower the pain threshold rather than raise it. Recovery from a single small dose is quick but accompanied by lingering drowsiness and gaps in memory, while repeated doses lead to progressively prolonged unconsciousness as the drug accumulates in fatty tissue and is slowly re-released.
Physical
The body load is one of profound central nervous system depression and sleep, without meaningful muscle relaxation or analgesia. At excessive doses or with too-rapid injection, dangerous drops in blood pressure and respiratory difficulties including apnea can occur.
Cognitive
The dominant cognitive features are the abrupt extinguishing of awareness on administration and unreliable memory surrounding the event, with retrograde amnesia reported after recovery.
Suppressions
Pharmacology
Pharmacodynamics
Thiopental acts primarily as a positive allosteric modulator at GABA-A receptors via the barbiturate binding site, increasing the duration of chloride ion channel opening and prolonging GABAergic inhibitory neurotransmission.citation needed As a barbiturate, it binds relatively non-selectively across a superfamily of ligand-gated ion channels: while it potentiates inhibitory GABA-A receptor currents, it blocks cation-permeable channels including neuronal nicotinic acetylcholine receptors at clinically relevant concentrations. Additional targets include ionotropic glutamate receptors (AMPA and kainate subtypes), which it antagonizes, and fatty-acid amide hydrolase 1 (FAAH1), which it inhibits.
Pharmacokinetics
Thiopental is highly lipophilic, with a lipid-water partition coefficient of approximately 10, and rapidly crosses the blood-brain barrier.citation needed Its brief clinical effect after a single intravenous dose results primarily from redistribution out of the central nervous system into muscle and adipose tissue, where it accumulates at concentrations 6 to 12 times greater than plasma levels. The free fraction in blood is then extensively metabolized in the liver, with only 0.3% of an administered dose excreted unchanged in urine. Ring desulfuration generates the active metabolite pentobarbital at approximately 3 to 10% of parent drug concentrations, while additional oxidation and hydroxylation pathways produce pharmacologically inert carboxylic acids and alcohols. Approximately 80% of circulating thiopental is bound to plasma protein.1 Elimination half-life estimates range from 3 to 26 hours, and the drug displays zero-order elimination kinetics during continuous infusion.citation needed
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Barbiturates, Other GABA-A receptor positive allosteric modulators
Harm Potential
Addiction & Dependence
Psychological
ModerateClassified as habit-forming with dependency risk, though recreational abuse is rare.citation needed
Physical
ModerateCarries a dependency risk as a barbiturate; recreational use is uncommon despite the potential for dependence.citation needed
Toxicity
Rapid or repeated intravenous injection can cause severe hypotension progressing to shock; this risk is heightened in trauma patients or those with pre-existing cardiovascular compromise.citation needed
Respiratory depression including apnea, laryngospasm, and coughing may occur with excessive or overly rapid injection.citation needed
Vesicant properties can cause severe tissue necrosis and sloughing if extravasated during intravenous injection; proper intravenous technique is essential to avoid local damage.1
History & Culture
Discovery and Development
Sodium thiopental was discovered in the early 1930s by Ernest H. Volwiler and Donalee L. Tabern while working for Abbott Laboratories.3 The compound was first administered to human beings on March 8, 1934, by Dr. Ralph M. Waters, who investigated its properties and…
Legality
By Country
United StatesPrescription medication (Withdrawn from market)References
Source Pages
Citations
- Pentothal. DailyMed (n.d.). https://dailymed.nlm.nih.gov/dailymed/archives/fdaDrugInfo.cfm?archiveid=487451234567891011
- D'Hollander S, Vander Laenen M, Gillet JB, De Deyne C, Heylen R, Boer W, & Jans F. (2013). Retrospective analysis of the hemodynamic effects of induction of barbiturate coma in patients with refractory elevated intracranial pressure. Critical Care. https://doi.org/10.1186/cc122681
- Sodium Thiopental | Chemistry World Podcast. (n.d.). https://www.chemistryworld.com/podcasts/sodium-thiopental/8360.article1
- The selection and use of essential medicines, 2025: WHO Model List of Essential Medicines, 24th list. World Health Organization (2025). https://www.who.int/publications/i/item/B094741
- The Legacy of the Anaesthesia 'Events' at Pearl Harbor, 7th December 1941. (n.d.). https://jmvh.org/article/the-legacy-of-the-anaesthesia-events-at-pearl-harbor-7th-december-1941/1
- The LSD Therapy Career of Jan Bastiaans, M.D.. (n.d.). https://maps.org/news-letters/v08n1/08118sne.html1
- Ohio Executes Killer with Single Drug. CBS News (2009-12-08). https://www.cbsnews.com/news/ohio-executes-killer-with-single-drug/1
- 21 CFR § 1308.13 — Schedule III Controlled Substances. U.S. Code of Federal Regulations (DEA / DOJ) (n.d.). https://ecfr.io/Title-21/Section-1308.131
- Hospira to pull out of sodium thiopental market. Manufacturing Chemist (2011-01-25). https://manufacturingchemist.com/hospira-to-pull-out-of-sodium-thiopental-market-588581
Further Reading
Article Status
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Recent changes8 human edits · latest
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21 August 2026
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24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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