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Chloral hydrate

Chloral hydrate
Systematic (IUPAC) name
CAS number 302-17-0
ATC code N05CC01
PubChem 2707
DrugBank ?
Chemical data
Formula C2H3Cl3O2 
Mol. mass 165.5 g/mol
Pharmacokinetic data
Bioavailability well absorbed
Metabolism converted to trichloroethanol, hepatic and renal
Half life 8–10 hours in plasma
Excretion bile, feces, urine (various metabolites not unchanged)
Therapeutic considerations
Pregnancy cat.


Legal status

Schedule IV(US)

Routes Oral capsule/syrup, rectal suppository

Chloral hydrate, also known as trichloroacetaldehyde monohydrate, 2,2,2-trichloro-1,1-ethanediol, and under the tradenames Aquachloral, Novo-Chlorhydrate, Somnos, Noctec, and Somnote, is a sedative and hypnotic drug as well as a chemical reagent and precursor. Its chemical formula is C2H3Cl3O2.

It was discovered through the chlorination of ethanol in 1832 by Justus von Liebig in Gießen. It was widely abused and misprescribed in the late 19th century. Chloral hydrate is soluble in both water and alcohol, readily forming concentrated solutions. A solution of chloral hydrate in alcohol called "knockout drops" was used to prepare a Mickey Finn.

It is a minor side-product of the chlorination of water, concentrations rarely exceeding 5 micrograms per litre (µg/l).



It is used for the short-term treatment of insomnia and as a sedative before minor medical or dental treatment. It was largely displaced by the mid-20th century by barbiturates [1] and subsequently by benzodiazepines. It was also formerly used in veterinary medicine as a general anesthetic. Today, it is commonly used as an ingredient in the veterinary anesthetic Equithesin.

In therapeutic doses for insomnia chloral hydrate is effective within sixty minutes, it is metabolized within 4 minutes into trichloroethanol by erythrocytes and plasma esterases and many hours later into trichloroacetic acid. Higher doses can depress respiration and blood pressure. An overdose is marked by confusion, convulsions, nausea and vomiting, severe drowsiness, slow and irregular breathing, cardiac arrhythmia and weakness. It may also cause liver damage and is 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].

The corresponding anhydrous aldehyde, chloral, is used as an intermediate in insecticide and herbicide manufacture (including DDT, dichlorvos, and naled). Chloral reacts rapidly with water to form chloral hydrate.

Chloral hydrate is now illegal in the United States without a prescription. Chloral hydrate is a schedule IV controlled substance in the United States. Its properties have sometimes led to its use as a date rape drug.

See also

  • Jennie Bosschieter (1882–1900) who was murdered in Paterson, New Jersey on October 19, 1900.
  • John Tyndall (1820-1893) who died of an accidental overdose.
  • Anna Nicole Smith (1967-2007) who died of an accidental[2] combination of chloral hydrate with three benzodiazepines, as announced by forensic pathologist Dr. Joshua Perper on 3/26/07. Chloral hydrate was the major factor, but none of these drugs would have been sufficient by itself to cause her death.[3]
  • Marilyn Monroe had chloral hydrate in her possession, and it has been speculated that it contributed to her death.[4]
  • Hank Williams came under the spell of a man calling himself "Doctor" Toby Marshall (actually a paroled forger), who often supplied him with prescriptions and injections of chloral hydrate, which Marshall claimed was a pain reliever.[5]
  • William S. Burroughs was expelled from school for experimenting with chloral hydrate along with another pupil. The incident is detailed in the writer's foreword to Junkie.
  • Mary Todd Lincoln was given chloral hydrate for sleep problems. See Mary Todd Lincoln by Jean Baker and Mary: Mrs. A. Lincoln, by Janis Cooke Newman.

Chloral in fiction and film

  • Bram Stoker, "Dracula," 1897
  • Edith Wharton, "The House of Mirth." New York, C. Schribner’s Sons, 1905.
  • Evelyn Waugh, Vile Bodies. London, Chapman & Hall Ltd., 1930.
  • Margery Allingham, "The Case of the Late Pig." Hodder & Stoughton, 1937.
  • Agatha Christie, "And Then There Were None." Dodd, Mead and Company, 1940.
  • Rex Stout, "The Final Deduction," Chapter 7. Viking Press, 1961.
  • From Russia with Love, Movie, 1963.
  • Jimmy Breslin, "The Gang That Couldn't Shoot Straight," 1969.
  • The Living Daylights, Movie, 1987.
  • Caleb Carr, "The Alienist." Random House, 1994.
  • Sarah Waters, Affinity. London: Virago Press, 1999.

See also

1905 novel “The House of Mirth” by Edith Wharton ( source: ) "Lily, honorable but not always smart in her decisions, has so fallen from her perch in New York society that she is living in a boarding house, and so broke that she needs to work for a living. She has quit one job, as secretary to a tasteless social climber, and has failed miserably at another, sewing for the fashionable milliner Mme. Regina, and to get through the nights has become addicted to chloral hydrate.

On the evening of her death, lonely and depressed, a step away from prostitution, she packs away her few remaining gowns and carefully settles her accounts, writing a check that will clear her last remaining debt, and then deliberately takes a larger dose than usual."


  1. ^ Tariq, Syed H. and Shailaja Pulisetty; “Pharmacotherapy for Insomnia”, Clinics in Geriatric Medicine (24), 2008 p. 93-105 PMID: 18035234
  2. ^ Anna Nicole Smith Autopsy Report. XI. Manner of death. A. The Exclusion of Homicide The Smoking Gun
  3. ^ Anna Nicole Smith Autopsy Released. Coroner: Ex-Playmate died from accidental sedative overdose The Smoking Gun
  4. ^ Marily Monroe. Theories Crime Library
  5. ^ Hank Williams summary Book Rags

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Chloral_hydrate". A list of authors is available in Wikipedia.
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