WHO Model Prescribing Information: Drugs Used in Anaesthesia
(1989; 60 pages) [French] View the PDF document
Table of Contents
View the documentPreface
View the documentIntroduction
Close this folderPremedication
View the documentAtropine
View the documentChloral hydrate
View the documentDiazepam
View the documentPromethazine
Open this folder and view contentsGeneral anaesthetics and oxygen
Open this folder and view contentsLocal anaesthetics
Open this folder and view contentsNon-opioid analgesics
Open this folder and view contentsOpioid analgesics and antagonists
Open this folder and view contentsMuscle relaxants and cholinesterase inhibitors
Open this folder and view contentsBlood substitutes
Open this folder and view contentsSolutions for correcting water and electrolyte imbalance
Open this folder and view contentsAntacid for use in obstetric practice
View the documentAnaesthesia at the District Hospital
View the documentSelected WHO publications of related interest
View the documentBack cover

Chloral hydrate

Group: sedative
Syrup: 200 mg in 5 ml

General information

Chloral hydrate is a sedative and hypnotic. The depressant effect on the central nervous system is believed to be due to an active metabolite, trichloroethanol. Its mechanism of action is unknown.

Chloral hydrate is rapidly absorbed from the gastrointestinal tract following oral or rectal administration. The depressant effect, which is evident within 30 minutes to 1 hour, persists for 6 to 8 hours. It is metabolized in the liver to the active metabolite trichloroethanol, which is subsequently excreted in the urine. The plasma half-life is 7 to 10 hours.

Clinical information


Preoperative medication to allay anxiety and to produce sedation.

Dosage and administration

Adults and children: 30 mg/kg 30 minutes before surgery.


• Known hypersensitivity to chloral hydrate.
• Hepatic or renal impairment.


The dosage should be reduced in patients with cardiac disease.

Ambulatory patients should be warned that chloral hydrate may impair their ability to drive or operate machinery for up to 24 hours.

Use in pregnancy

Chloral hydrate should be used during pregnancy only when the need outweighs any potential risk to the fetus.

Adverse effects

Gastric irritation is the most frequent adverse effect. Skin rashes may also occur.

Drug interactions

The hypoprothrombinaemic effect of coumarin anticoagulants may be intensified if such drugs are given concurrently with chloral hydrate.


Signs of overdose include increasing confusion, severe drowsiness leading to coma, hypotension, hypothermia and respiratory depression.


Induction of emesis or gastric lavage may be of value if undertaken within a few hours of ingestion. Otherwise, reliance must be placed on supportive measures such as maintenance of circulatory volume and mechanically assisted respiration.


Chloral hydrate syrup should be stored in tightly closed containers protected from light, below 25°C.

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