Clomethiazole

Clomethiazole

File:Clomethiazole Structural Formulae.png
Systematic (IUPAC) name
5-(2-chloroethyl)-4-methyl-1,3-thiazole
Clinical data
Routes of administration	Oral
Legal status
Legal status	UK: POM (Prescription only)
Identifiers
CAS Number	533-45-9
ATC code	N05CM02 (WHO)
PubChem	CID 10783
Chemical data
Formula	C6H8ClNS
Molar mass	161.653 g/mol[[]]

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.K, it is sold under the brand 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.

Pharmacology

Chlomethiazole acts as a positive allosteric modulator at the barbiturate/picrotoxin site of the GABA-A receptor. It works to enhance the action of the neurotransmitter GABA at this receptor. GABA is the major inhibitory neurotransmitter in the brain and produces anxiolytic, anticonvulsant, sedative, and hypnotic effects. Chlomethiazole 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. Chlomethiazole appears to also have another mechanism of action mediating some of its hypothermic and neuroprotective effects.

Adverse effects

Long term and frequent use of chlormethiazole can cause tolerance and physical dependence. Abrupt withdrawal may result in symptoms similar to those of sudden withdrawal of alcohol or benzodiazepines, including apnoeic-tonic seizures.

Overdose

Chlormethiazole is particularly toxic and dangerous in overdose. Overdose of chlormethiazole can be potentially fatal.

The Who drummer, Keith Moon, died from a massive overdose of chlormethiazole. The coroner determined he had consumed 32 tablets in total, the digestion of only 6 of which had been necessary to cause his death.

References

cs:Clomethiazol sv:Klometiazol