This information is intended for use by health professionals

1. Name of the medicinal product

Welldorm Tablets 707mg

Cloral Betaine 707mg Tablets

2. Qualitative and quantitative composition

Cloral Betaine 707mg Tablets contain 707mg cloral betaine, equivalent to 414mg of chloral hydrate.

3. Pharmaceutical form

Film coated tablets

4. Clinical particulars
4.1 Therapeutic indications

Cloral Betaine Tablets are used for the short-term treatment of severe insomnia which is interfering with normal daily life and where other therapies have failed.

Cloral Betaine Tablets should be used as an adjunct to non-pharmacological therapies.

The use of hypnotics in adolescents is not generally recommended and if used should be under the supervision of a medical specialist.

4.2 Posology and method of administration

Route of administration: oral. Cloral Betaine Tablets should be administered as a single daily dose, 15-30 minutes before bedtime with water or milk.

Adults and children 12 years and over: The usual dose is one to two tablets (414-828 mg). Higher doses should not exceed a maximum of 4 tablets (2g chloral hydrate) per dose.

Elderly: Dosage as for adults except for the frail elderly or those with hepatic impairment, where a reduction in dose may be appropriate.

Children: Cloral Betaine Tablets are not suitable for use in children under 12 years of age; for children between 2 and 11 years Chloral Hydrate 143mg per 5ml Oral Solution is recommended.

4.3 Contraindications

Cloral Betaine Tablets should not be used in patients with a marked hepatic or renal impairment, or in patients with severe cardiac disease. Should not be used in patients susceptible to acute attacks of porphyria.

4.4 Special warnings and precautions for use

Elderly patients are more likely experience the undesirable effects of hypnotics such as ataxia and confusion which may lead to falls and injury. For use in the frail elderly it is recommended that a lower dose be administered. (See 4.2 Posology and method of administration)

Best avoided in the presence of gastritis and in patients who have previously exhibited an idiosyncrasy or hypersensitivity to chloral hydrate.

4.5 Interaction with other medicinal products and other forms of interaction

Alcohol potentiates the sedative effect. Chloral hydrate followed by intravenous frusemide may result in sweating, hot flushes and variable blood pressure including hypertension due to a hypermetabolic state caused by displacement of thyroid hormone from its bound state. Delirium may occur, especially in the elderly, particularly when used in conjunction with psychotropics or anticholinergics. In patients taking anticoagulants, when chloral hydrate is added to or withdrawn from the drug regimen, or its dosage changed, careful monitoring of the prothrombin time is required.

Chloral Hydrate may interfere with laboratory tests of thyroid function.

4.6 Fertility, pregnancy and lactation

Cloral Betaine Tablets should not be used in pregnancy and lactation.

4.7 Effects on ability to drive and use machines

Patients receiving Cloral Betaine Tablets should be warned that their ability to drive or use machinery may be impaired by drowsiness.

4.8 Undesirable effects

Gastric irritation, abdominal distension and flatulence may occur. Excitement, tolerance, allergic skin reactions, headache and ketonuria have occasionally been reported. There is a danger of abuse or chronic intoxication and the possibility that habituation may develop. In such patients gastritis and parenchymatous renal injury may develop. After long term use, sudden withdrawal may result in delirium.

Elderly patients are more susceptible to the undesirable effects of hypnotic medications such as Cloral Betaine Tablets and are therefore more susceptible to ataxia, confusion, falls and injuries.

4.9 Overdose

The signs and symptoms of overdose involve the cardiovascular, respiratory and central nervous systems. These may include: respiratory depression, arrhythmias, hypothermia, pin-point pupils, hypotension or coma. Gastric irritation may result in vomiting and even gastric necrosis. If the patient survives, icterus due to hepatic damage and albuminuria from renal damage may appear. Serious problems have arisen with doses as little as 4g and l0g can be fatal. Overdosage should be treated with gastric lavage or inducing vomiting to empty the stomach. Supportive measures must be used. Haemodialysis, and in some cases haemoperfusion, have been reported to be effective in promoting the clearance of trichloroethanol.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Cloral Betaine Tablets are a chloral hydrate derivative, which leads to a decrease in sleep latency and in the number of awakenings. A near natural sleep is induced and the REM/Non-REM ratio is not altered.

5.2 Pharmacokinetic properties

Cloral betaine completely dissociates in solution to give chloral hydrate and trimethylglycine (betaine). Chloral hydrate and its metabolite tricloroethanol act as central nervous system depressants. Chloral hydrate is rapidly absorbed from the stomach, and starts to act within 30 minutes. It is widely distributed throughout the body, and is metabolised to trichloroethanol, also an active hypnotic, and trichloroacetic acid in the erythrocytes, liver and other tissues. It is excreted partly in the urine as trichloroethanol and its glucuronide, urochloralic acid, and as trichloroacetic acid. Significant amounts are also excreted in bile. Trichloroethanol has a plasma half life of the order of 8 hours. Trichloroacetic acid has a half-life of several days.

5.3 Preclinical safety data

Cloral betaine is hydrolysed in the stomach to chloral hydrate, which induces liver tumours in male mice, with no tumourigenic effects in rats. The mechanism of tumour induction is not known, but in the absence of clear evidence of mutagenic and clastogenic potential it is unlikely to be relevant in man.

6. Pharmaceutical particulars
6.1 List of excipients

In addition to the active ingredient, Cloral Betaine Tablets contain:



Maize starch

Ph. Eur.

Sodium citrate


Purified talc

Ph. Eur.

Magnesium stearate

Ph. Eur.


Ph. Eur.

Hydroxypropyl cellulose

Ph. Eur.

Polyethylene glycol

Ph. Eur.

Disodium edatate

Ph. Eur.

Carnoisine lake (E122)


Titanium dioxide (El71)


Brilliant blue FCF aluminium lake (E133)


6.2 Incompatibilities

None known

6.3 Shelf life

3 years

6.4 Special precautions for storage

Do not store above 25°C.

Do not refrigerate.

Store in the original package.

6.5 Nature and contents of container

Aluminium foil topped opaque PVC-PVdC blister packs each containing 4, 14 or 15 Cloral Betaine Tablets, presented in a carton – pack sizes 4, 28, 30, or 56.

6.6 Special precautions for disposal and other handling

No special requirements.

7. Marketing authorisation holder

Marlborough Pharmaceuticals Ltd, 35A High Street, Marlborough, Wiltshire, SN8 1LW

8. Marketing authorisation number(s)

PL 23138/0015

9. Date of first authorisation/renewal of the authorisation

10 August 2004

10. Date of revision of the text