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Systematic (IUPAC) name
CAS number 533-45-9
ATC code N05CM02
PubChem 10783
Chemical data
Formula C6H8ClNS 
Mol. mass 161.653 g/mol
Pharmacokinetic data
Bioavailability  ?
Metabolism  ?
Half life  ?
Excretion  ?
Therapeutic considerations
Pregnancy cat.


Legal status


Routes Oral

Clomethiazole (also called Chlormethiazole) is a sedative and hypnotic that is widely used in treating and preventing symptoms of acute alcohol withdrawal. It is a drug which is structurally related to thiamine (vitamin B1) but acts like a sedative, hypnotic, muscle relaxant and anticonvulsant. It is also used for the management of agitation, restlessness, short-term insomnia and Parkinson's disease in the elderly. In the U.S, it is sold under the brand, Distraneurin® (AstraZeneca Pharmaceuticals) and in the U.K, Heminevrin® (AstraZeneca Pharmaceuticals). Another brand name includes Nevrin® (in Romania). The drug is marketed either as a freebase in an oily suspension containing 192mg (about 3 grains) in capsule form, or as clomethiasole edisylate (ethane disulfonate) syrup.


Chlormethiazole acts on GABA receptors, which cause the release of the neurotransmitter GABA. GABA is a major inhibitory chemical in the brain involved in causing sleepiness and controlling anxiety and panic attacks. It acts by increasing the activity of GABA, thereby reducing the functioning of certain areas of the brain. This results in sleepiness, a decrease in anxiety and relaxation of muscles. It also inhibits the enzyme alcohol dehydrogenase, which is responsible for breaking down alcohol in the body. This slows the rate of elimination of alcohol from the body, which helps to relieve the sudden effects of alcohol withdrawal in alcoholics.

Adverse effects

When misused, chlormethiazole can cause tolerance and physical dependence. Abrupt withdrawal may result in symptoms similar to those of sudden withdrawal of alcohol.


  • The Who drummer, Keith Moon, died from an overdose of chlormethiazole. The coroner discovered 32 partially digested capsules in his stomach.[citation needed]
  • Abuse of this drug may involve the freebase being placed in a syringe and injected. This must be done quickly as the freebase is known to melt plastic.[citation needed]
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Clomethiazole". A list of authors is available in Wikipedia.
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