Chloral hydrate

Names
Trade names| Aquachloral, Novo-Chlorhydrate, Somnos, others
Other names| Trichloroacetaldehyde monohydrate

IUPAC name

* 2,2,2-Trichloroethane-1,1-diol

Clinical data
Main uses| Trouble sleeping, procedural sedation[1][2]
Side effects| Nausea, trouble with coordination, diarrhea[1]
Pregnancy
category|

* US: C (Risk not ruled out)

Routes of
use| By mouth, rectal suppository
External links
AHFS/Drugs.com| Monograph
Legal
Legal status|

* CA: Unscheduled
* US: Schedule IV

Pharmacokinetics
Bioavailability| Well absorbed
Metabolism| Liver and kidney (converted to trichloroethanol)
Elimination half-life| 8–10 hours
Excretion| Bile, feces, urine (various metabolites not unchanged)
Chemical and physical data
Formula| C2H3Cl3O2
Molar mass| 165.39 g·mol−1
3D model (JSmol)|

* Interactive image

Density| 1.9081 g/cm3 g/cm3
Melting point| 57 °C (135 °F)
Boiling point| 98 °C (208 °F)
Solubility in water| 660 g/100 ml[3]

SMILES

* ClC(Cl)(Cl)C(O)O

InChI

* InChI=1S/C2H3Cl3O2/c3-2(4,5)1(6)7/h1,6-7H

* Key:RNFNDJAIBTYOQL-UHFFFAOYSA-N

Chloral hydrate has been used as a medication to treat trouble sleeping and in procedural sedation.[1][2] Use is only recommended when safer medications are not appropriate.[1] It can be taken by mouth or used rectally.[1] Onset of effects are within an hour and may last for up to eight hours.[1] Other uses include as a part of a stain for fungal spores.[4]

Common side effects include nausea, trouble with coordination, and diarrhea.[1] Other side effects may include addiction, delirium tremens if suddenly stopped, and allergic reactions.[1] Use is not recommended during pregnancy.[5] Excessive doses may result in decrease breathing or coma.[2] How it works in not entirely clear.[1]

Chloral hydrate was discovered in 1832 by Justus von Liebig and came into medical use in the 1860s.[6] It is available as a generic medication in the United Kingdom were 30 tablets costs the NHS about 140 pounds as of 2020.[5] It is not approved for any medical use in the United States, though is still occasionally used.[7][8] It remains commonly used in neonatal intensive care units in Europe.[9] Historically it was used in mental asylums to manage agitation and was mixed in alcohol to create the "knockout drops" known as a Mickey Finn.[10][11]

## Contents

* 1 Uses
* 1.1 Medical
* 1.2 Botany and mycology
* 1.2.1 Hoyer's mounting medium
* 1.2.2 Melzer's reagent
* 1.3 Organic synthesis
* 2 Side effects
* 3 Pharmacology
* 3.1 Pharmacodynamics
* 3.2 Chemistry
* 4 History
* 5 Society and culture
* 5.1 Production
* 5.2 Legal status
* 5.3 Notable users
* 6 See also
* 7 References
* 8 External links

## Uses[edit | edit source]

### Medical[edit | edit source]

Chloral hydrate is used for the short-term treatment of insomnia and as a sedative before minor medical or dental treatment. It was largely displaced in the mid-20th century by barbiturates[12] and subsequently by benzodiazepines. It was also formerly used in veterinary medicine as a general anesthetic but is not considered acceptable for anesthesia or euthanasia of small animals due to adverse effects.[13] It is also still used as a sedative prior to EEG procedures, as it is one of the few available sedatives that does not suppress epileptiform discharges.[14]

In therapeutic doses for insomnia, chloral hydrate is effective within 20 to 60 minutes.[15] In humans it is metabolized within 7 hours into trichloroethanol and trichloroethanol glucuronide by erythrocytes and plasma esterases and into trichloroacetic acid in 4 to 5 days.[16] It has a very narrow therapeutic window making this drug difficult to use. Higher doses can depress respiration and blood pressure.

### Botany and mycology[edit | edit source]

More reputable uses of chloral hydrate include as a clearing agent for chitin and fibers and as a key ingredient in Hoyer's mounting medium, which is used to prepare permanent or semipermanent microscope slides of small organisms, histological sections, and chromosome squashes. Because of its status as a regulated substance, chloral hydrate can be difficult to obtain. This has led to chloral hydrate being replaced by alternative reagents[17][18] in microscopy procedures.

#### Hoyer's mounting medium[edit | edit source]

Chloral hydrate is also an ingredient used for Hoyer's solution, a mounting medium for microscopic observation of diverse plant types such as bryophytes, ferns, seeds, and small arthropods (especially mites). Other ingredients may include gum arabic and glycerol. An advantage of this medium includes a high refractive index and clearing (macerating) properties of small specimens (especially advantageous if specimens require observation with differential interference contrast microscopy).[citation needed]

#### Melzer's reagent[edit | edit source]

Chloral hydrate is an ingredient used to make Melzer's reagent, an aqueous solution that is used to identify certain species of fungi. The other ingredients are potassium iodide, and iodine. Whether tissue or spores react to this reagent is vital for the correct identification of some mushrooms.

### Organic synthesis[edit | edit source]

Chloral hydrate is a starting point for the synthesis of other organic compounds. It is the starting material for the production of chloral, which is produced by the distillation of a mixture of chloral hydrate and sulfuric acid, which serves as the desiccant.

Notably, it is used to synthesize isatin. In this synthesis, chloral hydrate reacts with aniline and hydroxylamine to give a condensation product which cyclicizes in sulfuric acid to give the target compound:[19]

Moreover, chloral hydrate is used as a reagent for the deprotection of acetals, dithioacetals and tetrahydropyranyl ethers in organic solvents.[20]

## Side effects[edit | edit source]

Chloral hydrate was routinely administered in gram quantities. Prolonged exposure to the vapors is unhealthy, however, with a LD50 for 4-hour exposure of 440 mg/m3. Long-term use of chloral hydrate is associated with a rapid development of tolerance to its effects and possible addiction as well as adverse effects including rashes, gastric discomfort and severe kidney, heart, and liver failure.[21]

Acute overdosage is often characterized by nausea, vomiting, confusion, convulsions, slow and irregular breathing, cardiac arrhythmia, and coma. The plasma, serum or blood concentrations of chloral hydrate and/or trichloroethanol, its major active metabolite, may be measured to confirm a diagnosis of poisoning in hospitalized patients or to aid in the forensic investigation of fatalities. Accidental overdosage of young children undergoing simple dental or surgical procedures has occurred. Hemodialysis has been used successfully to accelerate clearance of the drug in poisoning victims.[22] It is listed as having a "conditional risk" of causing torsades de pointes.[23]

## Pharmacology[edit | edit source]

### Pharmacodynamics[edit | edit source]

Chloral hydrate is metabolized in vivo to trichloroethanol, which is responsible for secondary physiological and psychological effects.[24]

Chloral hydrate is structurally and pharmacodynamically similar to ethchlorvynol (Placidyl), a pharmaceutical developed during the 1950s that was marketed as a hypnotic until 1999 when production was voluntarily ceased by manufacturers in favor of benzodiazepines. The metabolite of chloral hydrate exerts its pharmacological properties via enhancing the GABA receptor complex[25] and therefore is similar in action to benzodiazepines, nonbenzodiazepines and barbiturates. It can be moderately addictive, as chronic use is known to cause dependency and withdrawal symptoms. The chemical can potentiate various anticoagulants and is weakly mutagenic in vitro and in vivo.[citation needed]

### Chemistry[edit | edit source]

Chloral hydrate is a geminal diol with the formula C

3Cl

2. It is a colorless solid. It is derived from chloral (trichloroacetaldehyde) by the addition of one equivalent of water.

Chloral hydrate is soluble in both water and ethanol, readily forming concentrated solutions.

It is, together with chloroform, a minor side-product of the chlorination of water when organic residues such as humic acids are present. It has been detected in drinking water at concentrations of up to 100 micrograms per litre (µg/L) but concentrations are normally found to be below 10 µg/L. Levels are generally found to be higher in surface water than in ground water.[26]

## History[edit | edit source]

Chloral hydrate was first synthesized by the chemist Justus von Liebig in 1832 at the University of Giessen.[27] Through experimentation physiologist Claude Bernard clarified that the chloral hydrate was hypnotic as opposed to an analgesic.[28] Its sedative properties were observed by Rudolf Buchheim in 1861, but only described in detail and published by Oscar Liebreich in 1869;[29] subsequently, because of its easy synthesis, its use became widespread.[30]

It was the first of a long line of sedatives, most notably the barbiturates, manufactured and marketed by the German pharmaceutical industry.[27] Historically, chloral hydrate was utilized primarily as a psychiatric medication. In 1869, German physician and pharmacologist Oscar Liebreich began to promote its use to calm anxiety, especially when it caused insomnia.[31][28] Chloral hydrate had certain advantages over morphine for this application, as it worked quickly without injection and had a consistent strength. It achieved wide use in both asylums and the homes of those socially refined enough to avoid asylums. Upper- and middle-class women, well-represented in the latter category, were particularly susceptible to chloral hydrate addiction. After the 1904 invention of barbital, the first of the barbiturate family, chloral hydrate began to disappear from use among those with means.[27] It remained common in asylums and hospitals until the Second World War as it was quite cheap. Chloral hydrate had some other important advantages that kept it in use for five decades despite the existence of more advanced barbiturates. It was the safest available sedative until the middle of the twentieth century, and thus was particularly favored for children.[28] It also left patients much more refreshed after a deep sleep than more recently invented sedatives. Its frequency of use made it an early and regular feature in The Merck Manual.[32]

Chloral hydrate was also a significant object of study in various early pharmacological experiments. In 1875, Claude Bernard tried to determine if chloral hydrate exerted its action through a metabolic conversion to chloroform. This was not only the first attempt to determine whether different drugs were converted to the same metabolite in the body but also the first to measure the concentration of a particular pharmaceutical in the blood. The results were inconclusive.[33] In 1899 and 1901 Hans Horst Meyer and Ernest Overton respectively made the major discovery that the general anaesthetic action of a drug was strongly correlated to its lipid solubility. However, chloral hydrate was quite polar but nonetheless a potent hypnotic. Overton was unable to explain this mystery. Thus, chloral hydrate remained one of the major and persistent exceptions to this breakthrough discovery in pharmacology. This anomaly was eventually resolved in 1948, when Claude Bernard's experiment was repeated. While chloral hydrate was converted to a different metabolite than chloroform, it was found that was converted into the more lipophilic molecule 2,2,2-Trichloroethanol. This metabolite fit much better with the Meyer–Overton correlation than chloral had. Prior to this, it had not been demonstrated that general anesthetics could undergo chemical changes to exert their action in the body.[34]

Finally, chloral hydrate was also the first hypnotic to be used intravenously as a general anesthetic. In 1871, Pierre-Cyprien Oré began experiments on animals, followed by humans. While a state of general anesthesia could be achieved, the technique never caught on because its administration was more complex and less safe than the oral administration of chloral hydrate, and less safe for intravenous use than later general anesthetics were found to be.[35]

## Society and culture[edit | edit source]

Chloral hydrate was used as one of the earliest synthetic drugs to treat insomnia until 1912, when phenobarbital mostly replaced it.

In 1897, Bram Stoker's epistolary novel Dracula, one of its characters, Doctor John Seward, recorded his use and his molecular formula in his phonographic diary:

> I cannot but think of Lucy, and how different things might have been. If I don't sleep at once, chloral, the modern Morpheus— C2HCl3O . H2O! I should be careful not to let it grow into a habit. No I shall take none to-night! I have thought of Lucy, and I shall not dishonor her by mixing the two.[36]

In the conclusion of Edith Wharton's 1905 novel The House of Mirth, Lily Bart, the novel's heroine, becomes addicted to chloral hydrate and overdoses on the substance:

> She put out her hand and measured the soothing drops into a glass; but as she did so, she knew they would be powerless against the supernatural lucidity of her brain. She had long since raised the dose to its highest limit, but to-night she felt she must increase it. She knew she took a slight risk in doing so; she remembered the chemist's warning. If sleep came at all, it might be a sleep without waking.[37]

In the third season of the HBO drama series Oz, the drug is used by inmate Ryan O'Reily to aid his brother, Cyril O'Reily, during a boxing tournament by sneaking the drug into his opponent's drinking bottles, slowing the fighter down and allowing for Cyril to win his fights.

### Production[edit | edit source]

Chloral hydrate is produced from chlorine and ethanol in acidic solution.

4 Cl2 \+ C2H5OH + H2O → Cl3CCH(OH)2 \+ 5 HCl

In basic conditions the haloform reaction takes place and chloral hydrate is decomposed by hydrolysis to form chloroform.[38]

### Legal status[edit | edit source]

In the United States, chloral hydrate is a schedule IV controlled substance and requires a physician's prescription. Its properties have sometimes led to its use as a date rape drug.[39][40]

### Notable users[edit | edit source]

* Dante Gabriel Rossetti (1828–1882) became addicted to chloral, with whisky chasers, after the death of his wife Elizabeth Siddal from a laudanum overdose in 1862. He had a mental breakdown in 1872. He lived out the last ten years of his life addicted to chloral and alcohol, in part to mask the pain of botched surgery to an enlarged testicle in 1877.
* Irish physicist John Tyndall (1820–1893) died of an accidental overdose of chloral administered by his wife.
* Friedrich Nietzsche (1844–1900) regularly used chloral hydrate in the years leading up to his nervous breakdown, according to Lou Salome and other associates. Whether the drug contributed to his insanity is a point of controversy.[41]
* Psychologist and philosopher William James (1842-1910) who used the drug for insomnia and sedation due to chronic neurosis.
* King Chulalongkorn of Thailand (1853-1910) used the drug for a period after 1893 to relieve what may have been a mix of depression and unspecified illnesses. He is reported to have been taking one bottle per day during July 1894 although this was reduced after this time by his doctor.[42]
* André Gide (1869–1951) was given chloral hydrate as a boy for sleep problems by a physician named Lizart. Gide states in his autobiography If It Die... that "all my later weaknesses of will or memory I attribute to him."[43]
* Hank Williams (1923–1953) died from a combination of chloral hydrate, morphine and whiskey.[44][45][46]
* Marilyn Monroe (1926–1962) died from an overdose of chloral hydrate and pentobarbital (Nembutal).[47][48]
* Evelyn Waugh (1903–1966), insomniac for much of his adult life, for which 'in later life ... he became so deleteriously dependent on chloral'.[49] Waugh's novel, The Ordeal of Gilbert Pinfold, is largely a fictionalised account of an episode Waugh himself experienced as a result of excessive use of chloral in combination with bromide and alcohol. Waugh's friend and biographer Christopher Sykes observed that Waugh's description of D.G. Rossetti's demise under the effects of excessive use of chloral in his 1928 biography of the artist 'is a fairly exact description of how [Waugh's own] life ended in 1966'.[50]
* Montgomery Clift (1920–1966)[51]
* The Jonestown mass murder-suicides in 1978, involved the communal drinking of Flavor Aid poisoned with Valium, chloral hydrate, cyanide, and Phenergan.[52]
* Anna Nicole Smith (1967–2007) died of "combined drug intoxication" with chloral hydrate as the "major component."[53]
* Oliver Sacks (1933–2015) abused chloral hydrate in 1965 as a depressed insomniac. He found himself taking fifteen times the usual dose of chloral hydrate every night before he eventually ran out, causing violent withdrawal symptoms.[54]

## See also[edit | edit source]

* Chlorobutanol
* Disulfiram-like drug
* Trichloroethanol

## References[edit | edit source]

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 "Chloral Hydrate Monograph for Professionals". Drugs.com. Archived from the original on 23 January 2021. Retrieved 12 December 2020.
2. ↑ 2.0 2.1 2.2 "Chloral Hydrate 143mg/5ml Oral Solution - Summary of Product Characteristics (SmPC) - (emc)". www.medicines.org.uk. Archived from the original on 29 August 2021. Retrieved 12 December 2020.
3. ↑ "Chemical Book: Chloral hydrate". Archived from the original on 29 August 2018. Retrieved 27 February 2017.
4. ↑ Auerbach, Paul S. (2011). Wilderness Medicine E-Book: Expert Consult Premium Edition - Enhanced Online Features. Elsevier Health Sciences. p. 1278\. ISBN 978-1-4557-3356-9. Archived from the original on 2021-08-29. Retrieved 2020-12-12.
5. ↑ 5.0 5.1 BNF 79. London: Pharmaceutical Press. March 2020. p. 502\. ISBN 978-0857113658.
6. ↑ Stolerman, Ian (2010). Encyclopedia of Psychopharmacology. Springer Science & Business Media. p. 597\. ISBN 978-3-540-68698-9. Archived from the original on 2021-08-29. Retrieved 2020-12-12.
7. ↑ Dowd, Frank J.; Johnson, Bart; Mariotti, Angelo (2016). Pharmacology and Therapeutics for Dentistry - E-Book. Elsevier Health Sciences. p. 167\. ISBN 978-0-323-44595-5. Archived from the original on 2021-08-29. Retrieved 2020-12-12.
8. ↑ Meadows, Michelle (January–February 2007). "The FDA Takes Action Against Unapproved Drugs". FDA Consumer Magazine. 41 (1): 34–5. PMID 17342837. S2CID 37097870.
9. ↑ Lane, Robert H. (2014). Current Controversies in Perinatology, An Issue of Clinics in Perinatology, E-Book. Elsevier Health Sciences. p. 906\. ISBN 978-0-323-32673-5. Archived from the original on 2021-08-29. Retrieved 2020-12-12.
10. ↑ "Chloral Hydrate". Drug Enforcement Administration. Archived from the original on 11 May 2012. Retrieved 27 June 2018.
11. ↑ Young, Mary de (2014). Madness: An American History of Mental Illness and Its Treatment. McFarland. p. 248\. ISBN 978-0-7864-5746-5. Archived from the original on 2021-08-29. Retrieved 2020-12-12.
12. ↑ Tariq, Syed H.; Pulisetty, Shailaja (2008). "Pharmacotherapy for Insomnia". Clinics in Geriatric Medicine. 24 (1): 93–105. doi:10.1016/j.cger.2007.08.009. PMID 18035234.
13. ↑ Baxter, Mark G.; Murphy, Kathy L.; Taylor, Polly M.; Wolfensohn, Sarah E. (July 2009). "Chloral Hydrate Is Not Acceptable for Anesthesia or Euthanasia of Small Animals". Anesthesiology. 111 (1): 209–210. doi:10.1097/aln.0b013e3181a8617e. ISSN 0003-3022. PMID 19546703.
14. ↑ Mohammed M.S. Jan, MBChB, FRCP (C); Marilou F. Aquino, EEG Tech. "The use of chloral hydrate in pediatric electroencephalography" (PDF). Jcc.kau.edu.sa. Archived from the original (PDF) on 18 August 2011. Retrieved 15 November 2018.`{{cite web}}`: CS1 maint: multiple names: authors list (link)
15. ↑ Gauillard, J.; Cheref, S.; Vacherontrystram, M. N.; J. C., Martin (May–June 2002). "Chloral hydrate: a hypnotic best forgotten?". Encephale. 28 (3 Pt 1): 200–204. PMID 12091779.
16. ↑ Beland, Frederick A. "NTP Technical Report on the Toxicity and Metabolism Studies of Chloral Hydrate" (PDF). Toxicity Report Series Number 59. National Toxicology Program. p. 10\. Archived (PDF) from the original on 23 October 2011. Retrieved 14 March 2013.
17. ↑ Villani, Thomas S.; Koroch, Adolfina R.; Simon, James E. (2013). "An Improved Clearing and Mounting Solution to Replace Chloral Hydrate in Microscopic Applications". Applications in Plant Sciences. 1 (5): 1300016. doi:10.3732/apps.1300016. PMC 4105042. PMID 25202549.
18. ↑ Li, J.; Pan, L.; Naman, C. B.; Deng, Y.; Chai, H.; Keller, W. J.; Kinghorn, A. D. (2014). "Pyrrole Alkaloids with Potential Cancer Chemopreventive Activity Isolated from a Goji Berry-Contaminated Commercial Sample of African Mango". Journal of Agricultural and Food Chemistry. 62 (22): 5054–5060. doi:10.1021/jf500802x. PMC 4047925. PMID 24792835.
19. ↑ Marvel, C. S.; Hiers, G. S. (1941). "Isatin". Organic Syntheses.; Collective Volume, vol. 1, p. 327
20. ↑ Chandrasekhar, S.; Shrinidhi, A. (2014). "Chloral Hydrate as a Water Carrier for the Efficient Deprotection of Acetals, Dithioacetals, and Tetrahydropyranyl Ethers in Organic Solvents". Synthetic Communications. 44 (13): 1904–1913. doi:10.1080/00397911.2013.876652. S2CID 94886591.
21. ↑ Gelder, M.; Mayou, R.; Geddes, J. (2005). Psychiatry (3rd ed.). New York: Oxford. p. 238.
22. ↑ Baselt, R. (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, CA: Biomedical Publications. pp. 259–261.
23. ↑ "CredibleMeds :: Quicksearch". Crediblemeds.org. Archived from the original on 16 November 2018. Retrieved 15 November 2018.
24. ↑ Jira, Reinhard; Kopp, Erwin; McKusick, Blaine C.; Röderer, Gerhard; Bosch, Axel; Fleischmann, Gerald. "Chloroacetaldehydes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_527.pub2.
25. ↑ Lu, J.; Greco, M. A. (2006). "Sleep circuitry and the hypnotic mechanism of GABAA drugs". Journal of Clinical Sleep Medicine. 2 (2): S19–S26. doi:10.5664/jcsm.26527. PMID 17557503.
26. ↑ "Summary statement - 12.20 Chloral hydrate (trichloroacetaldehyde)" (PDF). World Health Organization. Archived (PDF) from the original on 21 October 2013. Retrieved 14 March 2013.
27. ↑ 27.0 27.1 27.2 Shorter, Edward (1998). A History of Psychiatry: From the era of the asylum to the age of Prozac. Wiley. ISBN 978-0471245315. OCLC 60169541.
28. ↑ 28.0 28.1 28.2 Dormandy, Thomas (2006). The Worst of Evils: The fight against pain. Yale University Press. ISBN 978-0300113228. OCLC 878623979.
29. ↑ Butler, Thomas C. (1970). "The Introduction of Chloral Hydrate into Medical Practice". Bulletin of the History of Medicine. 44 (2): 168–172. JSTOR 44450759. PMID 4914358.
30. ↑ Liebreich, Oskar (1869). Das Chloralhydrat : ein neues Hypnoticum und Anaestheticum und dessen Anwendung in der Medicin; eine Arzneimittel-Untersuchung [Chloral Hydrate: A new hypnotic and anaesthetic and its use in medicine; A drug study]. Berlin: Müller.
31. ↑ Shorter, Edward (2009). Before Prozac: The troubled history of mood disorders in psychiatry. Oxford University Press. ISBN 9780195368741. OCLC 299368559.
32. ↑ Cuadrado, Fernando F.; Alston, Theodore A. (October 2016). "Book Review". Journal of Anesthesia History. 2 (4): 153–155. doi:10.1016/j.janh.2016.01.004. ISSN 2352-4529.
33. ↑ Alston, Theodore A. (July 2016). "Noteworthy Chemistry of Chloroform". Journal of Anesthesia History. 2 (3): 85–88. doi:10.1016/j.janh.2016.04.008. ISSN 2352-4529. PMID 27480474.
34. ↑ Krasowski, Matthew D. (2003). "Contradicting a Unitary Theory of General Anesthetic Action: a History of Three Compounds from 1901 to 2001". Bulletin of Anesthesia History. 21 (3): 1–24. doi:10.1016/s1522-8649(03)50031-2. PMC 2701367. PMID 17494361.
35. ↑ Roberts, Matthew; Jagdish, S. (January 2016). "A History of Intravenous Anesthesia in War (1656–1988)". Journal of Anesthesia History. 2 (1): 13–21. doi:10.1016/j.janh.2015.10.007. ISSN 2352-4529. PMID 26898141. Archived from the original on 2021-08-29. Retrieved 2017-05-06.
36. ↑ Stoker, Bram (28 February 1897). Dracula. New York Grosset & Dunlap. Retrieved 28 February 2018 - via Internet Archive.
37. ↑ House of Mirth. www.gutenberg.org. June 1995. Archived from the original on 18 July 2018. Retrieved 2 July 2018.
38. ↑ Takahashi, Yasuo; Onodera, Sukeo; Morita, Masatoshi; Terao, Yoshiyasu (2003). "A Problem in the Determination of Trihalomethane by Headspace-Gas Chromatography/Mass Spectrometry" (PDF). Journal of Health Science. 49 (1): 3. doi:10.1248/jhs.49.1. Archived (PDF) from the original on 2014-03-27. Retrieved 2013-03-14.
39. ↑ McGregor, M. J.; Ericksen, J.; Ronald, L. A.; Janssen, P. A.; Van Vliet, A.; Schulzer, M. (2004). "Rising incidence of hospital-reported drug-facilitated sexual assault in a large urban community in Canada. Retrospective population-based study". Canadian Journal of Public Health. 95 (6): 441–445. doi:10.1007/BF03403990. PMC 6975915. PMID 15622794.
40. ↑ "Attacked by the Gang". The New York Daily News. 25 October 2008. Archived from the original on 3 April 2017. Retrieved 24 January 2018.
41. ↑ Cate, Curtis (2005). Friedrich Nietzsche. Woodstock, NY: The Overlook Press. p. 453.
42. ↑ "HM King Chulalongkorn's 1897 Journey to Europe". Archived from the original on 2021-03-01. Retrieved 2020-10-19.
43. ↑ Gide, André (2001) [1924]. If It Die...An Autobiography. Translated by Bussey, Dorothy. New York: Vintage International. p. 105.
44. ↑ Olson, Ted 2004, p. 296 harvnb error: no target: CITEREFOlson,_Ted2004 (help)
45. ↑ Olson, Ted 2004, p. 298 harvnb error: no target: CITEREFOlson,_Ted2004 (help)
46. ↑ Lilly, John. Hank's Lost Charleston Show. West Virginia Division of Culture and History.
47. ↑ Banner, Lois (2012). Marilyn: The Passion and the Paradox. Bloomsbury. pp. 411–412. ISBN 978-1-40883-133-5.
48. ↑ Spoto, Donald (2001). Marilyn Monroe: The Biography. Cooper Square Press. pp. 580–583. ISBN 978-0-8154-1183-3.
49. ↑ Hastings, Selina (1994). Evelyn Waugh: A Biography. Sinclair-Stevenson. p. 140\. ISBN 1-85619-223-7.
50. ↑ Sykes, Christopher (1977). Evelyn Waugh: A Biography. Penguin Books. p. 124.
51. ↑ Brando, Marlon; Lindsey, Robert (1994). Songs my mother taught me. New York: Random House. ISBN 978-0-09-943691-1.
52. ↑ Hall, John R. (1987). Gone from the Promised Land: Jonestown in American Cultural History. Transaction Publishers. p. 282\. ISBN 9780887388019. Archived from the original on 2020-03-12. Retrieved 2017-10-03.
53. ↑ "Smith died from accidental drug overdose". Archived from the original on 31 March 2007.
54. ↑ Sacks, Oliver (27 August 2012). "Altered States". The New Yorker. Archived from the original on 5 September 2015. Retrieved 2 September 2015.

## External links[edit | edit source]

Identifiers:|

* ATC code:

* N05CC01 (WHO)

* CAS Number: 302-17-0
* PubChem CID: 2707
* DrugBank:

* DB01563

* ChemSpider:

* 2606

* UNII:

* 418M5916WG

* KEGG:

* D00265

* ChEBI:

* CHEBI:28142

* ChEMBL:

* ChEMBL455917

|

* v
* t
* e

Hypnotics/sedatives (N05C)

GABAA|

| Alcohols|

* 2M2B
* Chloralodol
* Ethanol (alcohol)
* Diethylpropanediol
* Ethchlorvynol
* Methylpentynol
* Trichloroethanol

|

Barbiturates|

* Allobarbital
* Amobarbital
* Aprobarbital
* Barbital
* Butabarbital
* Butobarbital
* Cyclobarbital
* Ethallobarbital
* Heptabarb
* Hexobarbital
* Mephobarbital
* Methohexital
* Narcobarbital
* Pentobarbital
* Phenallymal
* Phenobarbital
* Propylbarbital
* Proxibarbal
* Reposal
* Secobarbital
* Talbutal
* Thiamylal
* Thiopental
* Thiotetrabarbital
* Vinbarbital
* Vinylbital

Benzodiazepines|

* Brotizolam
* Cinolazepam
* Climazolam
* clonazepam
* Doxefazepam
* Estazolam
* Flunitrazepam
* Flurazepam
* Flutoprazepam
* Lorazepam
* Loprazolam
* Lormetazepam
* Midazolam
* Nimetazepam
* Nitrazepam
* Phenazepam
* Quazepam
* Temazepam
* Triazolam

Carbamates|

* Carisoprodol
* Emylcamate
* Ethinamate
* Hexapropymate
* Meprobamate
* Methocarbamol
* Phenprobamate
* Procymate
* Tybamate

Imidazoles|

* Etomidate
* Metomidate
* Propoxate

Monoureides|

* Acecarbromal
* Apronal (apronalide)
* Bromisoval
* Capuride
* Carbromal
* Ectylurea

Neuroactive steroids|

* Acebrochol
* Allopregnanolone
* Alphadolone
* Alphaxolone
* Eltanolone
* Hydroxydione
* Minaxolone
* Progesterone

Nonbenzodiazepines|

* Eszopiclone
* Indiplon
* Lirequinil
* Necopidem
* Pazinaclone
* Saripidem
* Suproclone
* Suriclone
* Zaleplon
* Zolpidem
* Zopiclone

Phenols|

* Propofol

Piperidinediones|

* Glutethimide
* Methyprylon
* Pyrithyldione
* Piperidione

Quinazolinones|

* Afloqualone
* Cloroqualone
* Diproqualone
* Etaqualone
* Mebroqualone
* Mecloqualone
* Methaqualone
* Methylmethaqualone
* Nitromethaqualone
* SL-164

Others|

* Acetophenone
* Acetylglycinamide chloral hydrate
* Bromide compounds
* Lithium bromide
* Potassium bromide
* Sodium bromide
* Centalun
* Chloral betaine
* Chloral hydrate
* Chloralose
* Clomethiazole
* Dichloralphenazone
* Gaboxadol
* Kavalactones
* Loreclezole
* Paraldehyde
* Petrichloral
* Sulfonylalkanes
* Sulfonmethane (sulfonal)
* Tetronal
* Trional
* Triclofos
* Sesquiterpene
* Isovaleramide
* Isovaleric acid
* Valerenic acid

GABAB|

* 1,4-Butanediol
* 4-Fluorophenibut
* Aceburic acid
* Baclofen
* GABOB
* GHB (sodium oxybate)
* GBL
* GVL
* Phenibut
* Tolibut

H1|

| Antihistamines|

* Captodiame
* Cyproheptadine
* Diphenhydramine
* Doxylamine
* Hydroxyzine
* Methapyrilene
* Perlapine
* Pheniramine
* Promethazine
* Propiomazine

|

Antidepressants|

* Serotonin antagonists and reuptake inhibitors
* Etoperidone
* Nefazodone
* Trazodone
* Tricyclic antidepressants
* Amitriptyline
* Doxepin
* Trimipramine, etc.
* Tetracyclic antidepressants
* Mianserin
* Mirtazapine, etc.

Antipsychotics|

* Typical antipsychotics
* Chlorpromazine
* Thioridazine, etc.
* Atypical antipsychotics
* Olanzapine
* Quetiapine
* Risperidone, etc.

α2-Adrenergic|

* Clonidine
* Detomidine
* Dexmedetomidine
* Lofexidine
* Medetomidine
* Romifidine
* Tizanidine
* Xylazine

5-HT2A|

| Antidepressants|

* Trazodone
* Tricyclic antidepressants
* Amitriptyline
* Doxepin
* Trimipramine, etc.
* Tetracyclic antidepressants
* Mianserin
* Mirtazapine, etc.

|

Antipsychotics|

* Typical antipsychotics
* Chlorpromazine
* Thioridazine, etc.
* Atypical antipsychotics
* Olanzapine
* Quetiapine
* Risperidone, etc.

Others|

* Niaprazine

Melatonin|

* Agomelatine
* Melatonin
* Ramelteon
* Tasimelteon

Orexin|

* Almorexant
* Filorexant
* Lemborexant
* Suvorexant

α2δ VDCC|

* Gabapentin
* Gabapentin enacarbil
* Mirogabalin
* Phenibut
* Pregabalin

Others|

* Cannabidiol
* Cannabis
* Chlorophenylalkyldiols
* Fenpentadiol
* Metaglycodol
* Phenaglycodol
* Diethylpropanediol
* Evoxine
* Fenadiazole
* Guaifenesin-related muscle relaxants
* Chlorphenesin
* Mephenesin
* Mephenoxalone
* Metaxalone
* Methocarbamol
* Midaflur
* Opioids (e.g., morphine)
* Passion flower
* Scopolamine
* Trazodone
* UMB68
* Valnoctamide

* v
* t
* e

GABAA receptor positive modulators

Alcohols|

* Brometone
* Butanol
* Chloralodol
* Chlorobutanol (cloretone)
* Ethanol (alcohol) (alcoholic drink)
* Ethchlorvynol
* Isobutanol
* Isopropanol
* Menthol
* Methanol
* Methylpentynol
* Pentanol
* Petrichloral
* Propanol
* tert-Butanol (2M2P)
* tert-Pentanol (2M2B)
* Tribromoethanol
* Trichloroethanol
* Triclofos
* Trifluoroethanol

Barbiturates|

* (-)-DMBB
* Allobarbital
* Alphenal
* Amobarbital
* Aprobarbital
* Barbexaclone
* Barbital
* Benzobarbital
* Benzylbutylbarbiturate
* Brallobarbital
* Brophebarbital
* Butabarbital/Secbutabarbital
* Butalbital
* Buthalital
* Butobarbital
* Butallylonal
* Carbubarb
* Crotylbarbital
* Cyclobarbital
* Cyclopentobarbital
* Difebarbamate
* Enallylpropymal
* Ethallobarbital
* Eterobarb
* Febarbamate
* Heptabarb
* Heptobarbital
* Hexethal
* Hexobarbital
* Metharbital
* Methitural
* Methohexital
* Methylphenobarbital
* Narcobarbital
* Nealbarbital
* Pentobarbital
* Phenallymal
* Phenobarbital
* Phetharbital
* Primidone
* Probarbital
* Propallylonal
* Propylbarbital
* Proxibarbital
* Reposal
* Secobarbital
* Sigmodal
* Spirobarbital
* Talbutal
* Tetrabamate
* Tetrabarbital
* Thialbarbital
* Thiamylal
* Thiobarbital
* Thiobutabarbital
* Thiopental
* Thiotetrabarbital
* Valofane
* Vinbarbital
* Vinylbital

Benzodiazepines|

* 2-Oxoquazepam
* 3-Hydroxyphenazepam
* Adinazolam
* Alprazolam
* Arfendazam
* Avizafone
* Bentazepam
* Bretazenil
* Bromazepam
* Brotizolam
* Camazepam
* Carburazepam
* Chlordiazepoxide
* Ciclotizolam
* Cinazepam
* Cinolazepam
* Clazolam
* Climazolam
* Clobazam
* Clonazepam
* Clonazolam
* Cloniprazepam
* Clorazepate
* Clotiazepam
* Cloxazolam
* CP-1414S
* Cyprazepam
* Delorazepam
* Demoxepam
* Diazepam
* Diclazepam
* Doxefazepam
* Elfazepam
* Estazolam
* Ethyl carfluzepate
* Ethyl dirazepate
* Ethyl loflazepate
* Etizolam
* EVT-201
* FG-8205
* Fletazepam
* Flubromazepam
* Flubromazolam
* Fludiazepam
* Flunitrazepam
* Flunitrazolam
* Flurazepam
* Flutazolam
* Flutemazepam
* Flutoprazepam
* Fosazepam
* Gidazepam
* Halazepam
* Haloxazolam
* Iclazepam
* Imidazenil
* Irazepine
* Ketazolam
* Lofendazam
* Lopirazepam
* Loprazolam
* Lorazepam
* Lormetazepam
* Meclonazepam
* Medazepam
* Menitrazepam
* Metaclazepam
* Mexazolam
* Midazolam
* Motrazepam
* N-Desalkylflurazepam
* Nifoxipam
* Nimetazepam
* Nitrazepam
* Nitrazepate
* Nitrazolam
* Nordazepam
* Nortetrazepam
* Oxazepam
* Oxazolam
* Phenazepam
* Pinazepam
* Pivoxazepam
* Prazepam
* Premazepam
* Proflazepam
* Pyrazolam
* QH-II-66
* Quazepam
* Reclazepam
* Remimazolam
* Rilmazafone
* Ripazepam
* Ro48-6791
* Ro48-8684
* SH-053-R-CH3-2′F
* Sulazepam
* Temazepam
* Tetrazepam
* Tolufazepam
* Triazolam
* Triflubazam
* Triflunordazepam (Ro5-2904)
* Tuclazepam
* Uldazepam
* Zapizolam
* Zolazepam
* Zomebazam

Carbamates|

* Carisbamate
* Carisoprodol
* Clocental
* Cyclarbamate
* Difebarbamate
* Emylcamate
* Ethinamate
* Febarbamate
* Felbamate
* Hexapropymate
* Lorbamate
* Mebutamate
* Meprobamate
* Nisobamate
* Pentabamate
* Phenprobamate
* Procymate
* Styramate
* Tetrabamate
* Tybamate

Flavonoids|

* 6-Methylapigenin
* Ampelopsin (dihydromyricetin)
* Apigenin
* Baicalein
* Baicalin
* Catechin
* EGC
* EGCG
* Hispidulin
* Linarin
* Luteolin
* Rc-OMe
* Skullcap constituents (e.g., baicalin)
* Wogonin

Imidazoles|

* Etomidate
* Metomidate
* Propoxate

Kava constituents|

* 10-Methoxyyangonin
* 11-Methoxyyangonin
* 11-Hydroxyyangonin
* Desmethoxyyangonin
* 11-Methoxy-12-hydroxydehydrokavain
* 7,8-Dihydroyangonin
* Kavain
* 5-Hydroxykavain
* 5,6-Dihydroyangonin
* 7,8-Dihydrokavain
* 5,6,7,8-Tetrahydroyangonin
* 5,6-Dehydromethysticin
* Methysticin
* 7,8-Dihydromethysticin
* Yangonin

Monoureides|

* Acecarbromal
* Apronal (apronalide)
* Bromisoval
* Carbromal
* Capuride
* Ectylurea

Neuroactive steroids|

* Acebrochol
* Allopregnanolone (brexanolone)
* Alfadolone
* Alfaxalone
* 3α-Androstanediol
* Androstenol
* Androsterone
* Certain anabolic-androgenic steroids
* Cholesterol
* DHDOC
* 3α-DHP
* 5α-DHP
* 5β-DHP
* DHT
* Etiocholanolone
* Ganaxolone
* Hydroxydione
* Minaxolone
* ORG-20599
* ORG-21465
* P1-185
* Pregnanolone (eltanolone)
* Progesterone
* Renanolone
* SAGE-105
* SAGE-324
* SAGE-516
* SAGE-689
* SAGE-872
* Testosterone
* THDOC
* Zuranolone

Nonbenzodiazepines|

* Cyclopyrrolones: Eszopiclone
* Pagoclone
* Pazinaclone
* Suproclone
* Suriclone
* Zopiclone

* Imidazopyridines: Alpidem
* DS-1
* Necopidem
* Saripidem
* Zolpidem

* Pyrazolopyrimidines: Divaplon
* Fasiplon
* Indiplon
* Lorediplon
* Ocinaplon
* Panadiplon
* Taniplon
* Zaleplon

* Others: Adipiplon
* CGS-8216
* CGS-9896
* CGS-13767
* CGS-20625
* CL-218,872
* CP-615,003
* CTP-354
* ELB-139
* GBLD-345
* Imepitoin
* JM-1232
* L-838,417
* Lirequinil (Ro41-3696)
* NS-2664
* NS-2710
* NS-11394
* Pipequaline
* ROD-188
* RWJ-51204
* SB-205,384
* SX-3228
* TGSC01AA
* TP-003
* TPA-023
* TP-13
* U-89843A
* U-90042
* Viqualine
* Y-23684

Phenols|

* Fospropofol
* Propofol
* Thymol

Piperidinediones|

* Glutethimide
* Methyprylon
* Piperidione
* Pyrithyldione

Pyrazolopyridines|

* Cartazolate
* Etazolate
* ICI-190,622
* Tracazolate

Quinazolinones|

* Afloqualone
* Cloroqualone
* Diproqualone
* Etaqualone
* Mebroqualone
* Mecloqualone
* Methaqualone
* Methylmethaqualone
* Nitromethaqualone
* SL-164

Volatiles/gases|

* Acetone
* Acetophenone
* Acetylglycinamide chloral hydrate
* Aliflurane
* Benzene
* Butane
* Butylene
* Centalun
* Chloral
* Chloral betaine
* Chloral hydrate
* Chloroform
* Cryofluorane
* Desflurane
* Dichloralphenazone
* Dichloromethane
* Diethyl ether
* Enflurane
* Ethyl chloride
* Ethylene
* Fluroxene
* Gasoline
* Halopropane
* Halothane
* Isoflurane
* Kerosine
* Methoxyflurane
* Methoxypropane
* Nitric oxide
* Nitrogen
* Nitrous oxide
* Norflurane
* Paraldehyde
* Propane
* Propylene
* Roflurane
* Sevoflurane
* Synthane
* Teflurane
* Toluene
* Trichloroethane (methyl chloroform)
* Trichloroethylene
* Vinyl ether

Others/unsorted|

* 3-Hydroxybutanal
* α-EMTBL
* AA-29504
* Avermectins (e.g., ivermectin)
* Bromide compounds (e.g., lithium bromide, potassium bromide, sodium bromide)
* Carbamazepine
* Chloralose
* Chlormezanone
* Clomethiazole
* DEABL
* Dihydroergolines (e.g., dihydroergocryptine, dihydroergosine, dihydroergotamine, ergoloid (dihydroergotoxine))
* DS2
* Efavirenz
* Etazepine
* Etifoxine
* Fenamates (e.g., flufenamic acid, mefenamic acid, niflumic acid, tolfenamic acid)
* Fluoxetine
* Flupirtine
* Hopantenic acid
* Lanthanum
* Lavender oil
* Lignans (e.g., 4-O-methylhonokiol, honokiol, magnolol, obovatol)
* Loreclezole
* Menthyl isovalerate (validolum)
* Monastrol
* Niacin
* Nicotinamide (niacinamide)
* Org 25,435
* Phenytoin
* Propanidid
* Retigabine (ezogabine)
* Safranal
* Seproxetine
* Stiripentol
* Sulfonylalkanes (e.g., sulfonmethane (sulfonal), tetronal, trional)
* Terpenoids (e.g., borneol)
* Topiramate
* Valerian constituents (e.g., isovaleric acid, isovaleramide, valerenic acid, valerenol)

* Unsorted benzodiazepine site positive modulators: α-Pinene
* MRK-409 (MK-0343)
* TCS-1105
* TCS-1205

See also: Receptor/signaling modulators • GABA receptor modulators • GABA metabolism/transport modulators

* v
* t
* e

Glycine receptor modulators

Receptor
(ligands)|

| GlyR|

* Agonists: β-Alanine
* β-ABA (BABA)
* β-AIBA
* Caesium
* D-Alanine
* D-Serine
* GABA
* Glycine
* Hypotaurine
* Ivermectin
* L-Alanine
* L-Proline
* L-Serine
* L-Threonine
* MDL-27531
* Milacemide
* Picolinic acid
* Propofol
* Quisqualamine
* Sarcosine
* Taurine

* Positive modulators: Alcohols (e.g., brometone, chlorobutanol (chloretone), ethanol (alcohol), tert-butanol (2M2P), tribromoethanol, trichloroethanol, trifluoroethanol)
* Alkylbenzene sulfonate
* Anandamide
* Barbiturates (e.g., pentobarbital, sodium thiopental)
* Chlormethiazole
* D12-116
* Dihydropyridines (e.g., nicardipine)
* Etomidate
* Ginseng constituents (e.g., ginsenosides (e.g., ginsenoside-Rf))
* Glutamic acid (glutamate)
* Ivermectin
* Ketamine
* Neuroactive steroids (e.g., alfaxolone, pregnenolone (eltanolone), pregnenolone acetate, minaxolone, ORG-20599)
* Nitrous oxide
* Penicillin G
* Propofol
* Tamoxifen
* Tetrahydrocannabinol
* Triclofos
* Tropeines (e.g., atropine, bemesetron, cocaine, LY-278584, tropisetron, zatosetron)
* Volatiles/gases (e.g., chloral hydrate, chloroform, desflurane, diethyl ether (ether), enflurane, halothane, isoflurane, methoxyflurane, sevoflurane, toluene, trichloroethane (methyl chloroform), trichloroethylene)
* Xenon
* Zinc

* Antagonists: 2-Aminostrychnine
* 2-Nitrostrychnine
* 4-Phenyl-4-formyl-N-methylpiperidine
* αEMBTL
* Bicuculline
* Brucine
* Cacotheline
* Caffeine
* Colchicine
* Colubrine
* Cyanotriphenylborate
* Dendrobine
* Diaboline
* Endocannabinoids (e.g., 2-AG, anandamide (AEA))
* Gaboxadol (THIP)
* Gelsemine
* iso-THAZ
* Isobutyric acid
* Isonipecotic acid
* Isostrychnine
* Laudanosine
* N-Methylbicuculline
* N-Methylstrychnine
* N,N-Dimethylmuscimol
* Nipecotic acid
* Pitrazepin
* Pseudostrychnine
* Quinolines (e.g., 4-hydroxyquinoline, 4-hydroxyquinoline-3-carboxylic acid, 5,7-CIQA, 7-CIQ, 7-TFQ, 7-TFQA)
* RU-5135
* Sinomenine
* Strychnine
* Thiocolchicoside
* Tutin

* Negative modulators: Amiloride
* Benzodiazepines (e.g., bromazepam, clonazepam, diazepam, flunitrazepam, flurazepam)
* Corymine
* Cyanotriphenylborate
* Daidzein
* Dihydropyridines (e.g., nicardipine, nifedipine, nitrendipine)
* Furosemide
* Genistein
* Ginkgo constituents (e.g., bilobalide, ginkgolides (e.g., ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, ginkgolide M))
* Imipramine
* NBQX
* Neuroactive steroids (e.g., 3α-androsterone sulfate, 3β-androsterone sulfate, deoxycorticosterone, DHEA sulfate, pregnenolone sulfate, progesterone)
* Opioids (e.g., codeine, dextromethorphan, dextrorphan, levomethadone, levorphanol, morphine, oripavine, pethidine, thebaine)
* Picrotoxin (i.e., picrotin and picrotoxinin)
* PMBA
* Riluzole
* Tropeines (e.g., bemesetron, LY-278584, tropisetron, zatosetron)
* Verapamil
* Zinc

|

NMDAR|

* See here instead.

Transporter
(blockers)|

| GlyT1|

* ACPPB
* ALX-1393
* ALX-5407 (NFPS)
* AMG-747
* ASP2535
* BIIB-104 (PF-04958242)
* Bitopertin (RG1678/RO4917838)
* CP-802079
* Ethanol (alcohol)
* Glycyldodecylamide
* GSK1018921
* LY-2365109
* ORG-24598
* ORG-25935 (SCH-900435)
* PF-02545920
* PF-03463275
* Sarcosine
* SSR-103,800
* SSR-504,734

|

GlyT2|

* Amoxapine
* Ethanol (alcohol)
* NAGly
* Opiranserin (VVZ-149)
* ORG-25543
* VVZ-368

See also
Receptor/signaling modulators
GABA receptor modulators
GABAA receptor positive modulators
Ionotropic glutamate receptor modulators
*[US]: United States
*[CA]: Canada
*[CID]: Compound ID
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template
*[α2δ]: alpha2delta subunit
*[VDCC]: voltage-gated calcium channel
*[GABA]: γ-Aminobutyric acid
*[GlyR]: Glycine receptor
*[NMDAR]: N-Methyl-D-aspartate receptor
*[GlyT1]: Glycine transporter 1
*[GlyT2]: Glycine transporter 2