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Created Mar 2019 | Updated Oct 2020


  • [NOCTEC]

DEA CODE 2465: Schedule 4

Slip you a Mickey:
You know how in those old movies, people would slip a "Mickey Finn" into a drink to knock someone unconscious? It was supposed to be chloral hydrate. An early sleep medication, chloral hydrate was used to knock people out either to help them sleep, or more nefariously, as a date-rate type substance. The Mickey Finn or "knockout drops" ended up being a mixture of chloral hydrate and alcohol, which are both depressants.

This medicine has been around for over a century and a half, having first been synthesized in 1832. Indeed, it's about the oldest synthetic drug. Doctors rarely prescribe it these days, although in rare cases it ends up being a second-line sleep agent for elderly patients.

The first synthetically produced sedative-hypnotic drug:
commonly used in the late 19th century to treat insomnia and still occasionally used to reduce anxiety or produce sleep before surgery. Chloral hydrate acts as a depressant on the central nervous system, with sedative effects similar to those of barbiturates. First synthesized in 1832, but it was not introduced into medicine until 1869. A therapeutic dose produces a deep sleep lasting four to eight hours with few after effects, but habitual use of the drug results in addiction - a fact quickly noted in the medical literature of the late 19th and the early 20th century.

Symptoms of overdose may include deep stupor, dilation of blood vessels, fall in blood pressure and body temperature, and slowed respiration. In a severe overdose, death usually occurs within 5 to 10 hours. Chloral hydrate was the primary ingredient, along with alcohol, of the "knockout drops" or "Mickey Finns" of popular lore. With the development of safer and more effective drugs, the use of chloral hydrate has declined.

Summary of Use During Lactation:
Short-term or occasional use of chloral hydrate during breastfeeding is unlikely to adversely affect the breastfed infant, especially if the infant is older than 2 months.

Because the active metabolite of chloral hydrate has a long half-life, other sedative-hypnotics are preferred for long-term use during breastfeeding, especially while nursing a neonate or preterm infant. Monitor the infant for excessive drowsiness.

Alternate Drugs to Consider:

Chloral hydrate

Chloral Hydrate, a sedative drug discovered in 1832 with a history of recreational use going back to the 19th century. Sometimes prescribed for extreme insomnia. For such an old drug, relatively little is known about its long-term term effects on the body. Produces intoxication comparable to alcohol or benzodiazepines.

RouteOnsetDurationAfter Effects
Tripsit Factsheets
All ROAs:20-60 minutes5-10 hours2-6 hours
Chloral hydrate Duration
All other CNS depressants.
  • chloral-hydrate
  • aquachloral
  • somnos

Despite many years of use, chloral hydrate has not been implicated in causing serum enzyme elevations or clinically apparent liver injury.

Chloral hydrate Hepatotoxicity:
Chloral hydrate has been in clinical use for many decades and has not been linked to serum enzyme elevations during therapy or instances of clinically apparent liver injury. While prospective studies of the effects of chloral hydrate on liver tests have not been done, the absence of reported instances of liver injury attributable to chloral hydrate suggests that it has little or no hepatic toxicity. Chloral hydrate has been linked to hypersensitivity reactions such as rash, fever and eosinophilia. Chloral hydrate also has major drug-drug interactions with oral anticoagulants, antidepressants and alcohol. In patients with cirrhosis and hepatic decompensation, chloral hydrate can trigger or worsen hepatic encephalopathy.

E Likelihood score: E (unlikely cause of clinically apparent liver injury).

Chloral Hydrate Oral User Reviews:
22 Total User Reviews
Chloral Hydrate Oral Read Reviews
Condition: Cronic Trouble Sleeping (15 Reviews):

Ease of Use(4.53)


Chloral hydrate:

Chloral hydrate has not been approved by the FDA in the United States or the EMA in the European Union for any medical indication and is on the FDA list of unapproved drugs that are still prescribed by clinicians. However, chloral hydrate products, licensed for short-term management of severe insomnia, are available in the United Kingdom.

  • 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 and subsequently by benzodiazepines.
  • It is also a useful laboratory chemical reagent and precursor.
  • It was discovered in 1832
  • It is a colorless solid
  • In therapeutic doses for insomnia, chloral hydrate is effective within 20 to 60 minutes.
  • Chloral hydrate was used as one of the earliest synthetic drugs to treat insomnia until 1912, when phenobarbital replaced it and made its use unnecessary.

Notable Chloral Hydrate Users:

  • Hank Williams (1923-1953):
    Died from a combination of chloral hydrate, morphine and whiskey.
  • Marilyn Monroe (1926-1962):
    Died from an overdose of chloral hydrate and pentobarbital (Nembutal)
  • The Jonestown mass murder-suicides (1978):
    Involved the communal drinking of Flavor Aid poisoned with Valium, chloral hydrate, cyanide, and Phenergan.
  • Anna Nicole Smith (1967-2007):
    Died of "combined drug intoxication" with chloral hydrate as the "major component.

It was discovered in 1832 by Justus von Liebig in Gieben when a chlorination (halogenation) reaction was performed on ethanol. Its sedative properties were observed by Rudolf Buchheim in 1861, but only described in detail and published by Oscar Liebreich in 1869; subsequently, because of its easy synthesis, its use became widespread. It was widely used for sedation in asylums and in general medical practice, and also became a popular drug of abuse in the late 19th century.

Chloral hydrate is soluble in both water and ethanol, readily forming concentrated solutions. A solution of chloral hydrate in ethanol called "knockout drops" was used to prepare a Mickey Finn

Related Substances:
Created Mar 2019 | Updated Oct 2020



DEA CODE 2460: Schedule 4

Sedative Hypnotic Drug:
One of a group of medicines called hypnotics ('sleeping tablets'). Cloral betaine rapidly breaks down in the stomach to form chloral hydrate. Welldorm tablets are used for the short-term treatment of severe insomnia (sleeping problems) which is interfering with normal daily life.Welldorm will normally be given in addition to other non drug therapies e.g. counseling. Welldorm is normally used in adolescents under the supervision of a medical specialist.

Cloral Betaine Tablets are used for the short-term treatment of severe insomnia which is interfering with normal daily life and where other therapies have failed. Cloral Betaine Tablets should be used as an adjunct to non-pharmacological therapies. The use of hypnotics in adolescents is not generally recommended and if used should be under the supervision of a medical specialist.

EMC PDF Cloral Betaine

Chloral Betaine

Sedative-hypnotic drug that was introduced into the United States in the 60's.

RouteOnsetDurationAfter Effects
Tripsit Factsheets
All ROAs:15-30 minutes3-7 hours2-8 hours
Chloral Betaine Duration

Chloral betaine:
  • A sedative-hypnotic drug
  • It was introduced in the United States in 1963

Acts as an extended-acting formulation of chloral hydrate which is then metabolized into trichloroethanol, which is responsible for most or all of its effects.

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