Chloral hydrate

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Chloral hydrate
Systematic (IUPAC) name
2,2,2-trichloroethane-1,1-diol
Identifiers
CAS number	302-17-0
ATC code	N05 CC01
PubChem	2707
DrugBank	?
Chemical data
Formula	C₂H Cl₃O·H₂O
Mol. weight	165.5
Pharmacokinetic data
Bioavailability	unknown
Metabolism	liver, erythrocytes
Half life	7–10 hours in plasma
Excretion	bile, feces, urine (various metabolites not unchanged)
Therapeutic considerations
Pregnancy cat.	C
Legal status	Schedule IV
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 C₂H Cl₃O · H₂O.

It is used for the short-term treatment of insomnia and as a sedative before minor medical or dental treatment. It has been largely displaced by the development of benzodiazepines. It was also formerly used as 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 it is effective within sixty minutes, it is rapidly metabolized into trichloroethanol and 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. It is moderately addictive. Chronic use can cause dependency and withdrawal symptoms. It can potentiate various anticoagulants and is weakly mutagenic in vitro and in vivo.

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.

A solution of chloral hydrate in alcohol is called "knockout drops" used in Mickey Finns.

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

The anhydrous form is an intermediate in insecticide and herbicide manufacture (including DDT, dichlorvos, and naled).

Chloral hydrate is now illegal in the United States without a prescription. Chloral hydrate is a schedule IV controlled substance in the United States.