Sedative-hypnotic (thiamine analogue) Pregnancy: Do not use in pregnancy, especially during the first and last trimesters, unless there are compelling reasons - there is no evidence of safety in human pregnancy nor animal evidence that it is entirely free from hazard. Clomethiazole is excreted into breast milk; use in nursing mothers only where the physician considers the benefit outweighs the possible hazard to the infant. No human fertility data (SPC 4.6).

Clomethiazole

Brand names: Heminevrin

Clomethiazole is a sedative and hypnotic used for severe insomnia in the elderly and for acute alcohol withdrawal in a closely supervised setting.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One 192 mg capsule (management of restlessness and agitation in the elderly)

Route: Oral

Frequency: Three times daily

Source product is Clomethiazole 192 mg Capsules; the SPC expresses all doses in capsules. Severe insomnia in the elderly: 1-2 capsules before going to bed - the lower dose should be tried first. Alcohol withdrawal states: clomethiazole is not a specific cure for alcoholism; treat in hospital or, exceptionally, on an outpatient basis by specialist units with close daily monitoring of the dose. Adjust to patient response - the patient should be sedated but rousable. Suggested regimen: initial dose 2 to 4 capsules, repeated after some hours if necessary; day 1 (first 24 hours) 9 to 12 capsules divided into 3 or 4 doses; day 2, 6 to 8 capsules divided into 3 or 4 doses; day 3, 4 to 6 capsules divided into 3 or 4 doses; days 4 to 6, a gradual reduction in dosage until the final dose. Administration for more than nine (9) days is not recommended. As with all psychotropic drugs, keep treatment to a minimum, review regularly and discontinue as soon as possible. Do not prescribe to patients who continue to drink or abuse alcohol - alcohol combined with clomethiazole, particularly in alcoholics with cirrhosis, can lead to fatal respiratory depression even with short-term use. Moderate liver disorders associated with alcoholism do not preclude use, though increased systemic availability and delayed elimination may require reduced dosage; great caution with gross liver damage and decreased liver function. Elderly: increased bioavailability and delayed elimination. Paediatric: safety and efficacy in children and adolescents under 18 years has not been established and oral clomethiazole is not recommended for use in children. Capsules must be swallowed whole with water and not chewed, crushed or broken.

Dose adjustments

Renal

Caution should be observed in patients with chronic renal disease; no numeric dose adjustment is stated (SPC 4.4).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Acute pulmonary insufficiency

Side effects

Nasal congestion and irritation - the most common effect, occurring 15 to 20 minutes after ingestion, occasionally severe and associated with severe headache; increased nasopharyngeal/bronchial secretions
Conjunctival irritation
Excessive sedation, especially with higher doses or when given to the elderly for daytime sedation; headache
Gastrointestinal disturbances; reversible increases of transaminases or bilirubin
Rash and urticaria; rarely bullous skin eruptions; rare anaphylactic reactions
Physical dependence, tolerance and withdrawal reactions with prolonged use above recommended doses; paradoxical excitement or confusion (rare)

Interactions

Centrally acting depressant drugs including alcohol and benzodiazepines - clomethiazole may potentiate or be potentiated; fatal cardiorespiratory collapse has been reported with concomitant CNS depressants, so dosage should be appropriately reduced (SPC 4.4)
Clomethiazole is an inhibitor of CYP2A6 and CYP2E1 - plasma clearance of CYP2E1 substrates may be decreased (a threefold decrease in plasma clearance was shown for chlorzoxazone)
Possible effect on the metabolism of other clinically relevant CYP2E1 substrates including sedatives, anaesthetics, analgesics, antidepressants and antiepileptics (SPC 4.5 truncated at the source-fetch limit - list incomplete)

Clinical monograph

How it works

It has sedative, hypnotic and anticonvulsant properties, thought to act largely by enhancing GABA-A receptor activity.

Prescribing in practice

There is a marked risk of dependence and of fatal respiratory depression if combined with alcohol, so it should not be given to patients who continue to drink and should be used only short-term.
Excessive respiratory secretions and sedation can occur, particularly in the elderly and in respiratory disease.
Avoid in acute pulmonary insufficiency and use cautiously in hepatic impairment.

Monitoring

Monitor conscious level, respiratory status and signs of dependence during treatment.

Counselling the patient

Never take this medicine with alcohol.
It causes drowsiness; do not drive if affected.
Use it only for a short time as prescribed.

Evidence & guidelines

Use is guided by the SPC and established practice, with short-term use emphasised because of dependence and interaction risks.

Reference: SmPC Heminevrin; NICE CG115 (Alcohol-Use Disorders Management); BAP Substance Misuse Guidelines 2012; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways