4.1. Therapeutic indications

Alimemazine has powerful antihistamine and anti-emetic actions and is used in the management of urticaria and pruritus.

Alimemazine may be used in pre-medication as a sedative before anaesthesia in children aged between 2 to 7 years. The alimemazine syrup formulation is suitable for these indications in children.

4.2. Posology and method of administration

Posology

Do NOT exceed the recommended dose (see also section 4.9).

Urticaria and pruritus

Adults: 10mg two or three times daily.

Elderly: Dosage should be reduced to 10mg once or twice daily.

Paediatric population:

Not recommended for infants less than 2 years old.

Children over 2 years of age: The use of Alimemazine Syrup is recommended.

As a sedative before anaesthesia

The dosage for children is best achieved by use of Alimemazine Syrup.

Method of administration

Oral

4.3. Contraindications

Hypersensitivity to the active substance, phenothiazines or to any of the excipients listed in section 6.1.

Use in patients with hepatic or renal dysfunction, epilepsy, Parkinson's disease, hypothyroidism, phaeochromocytoma, myasthenia gravis, and prostatic hypertrophy.

Use in patients with history of narrow angle glaucoma and agranulocytosis.

Use in children less than 2 years of age (see Section 4.4).

4.4. Special warnings and precautions for use

Precautions for use:

Alimemazine should be used with caution in:

- Elderly or volume depleted patients who are more susceptible to orthostatic hypotension (see section 4.8)

- Elderly patients presenting chronic constipation (risk of paralytic ileus),

- Elderly patients with possible prostatic hypertrophy (see section 4.3);

- Elderly patients in hot and cold weather (risk of hyper/hypothermia) (see section 4.8)

- Patients with certain cardiovascular diseases alimemazine may cause arrhythmias due to the tachycardia-inducing and hypotensive effects of phenothiazines (see section 4.8)

- Patients with seizures (see section 4.8).

Paediatric population:

Alimemazine is contraindicated for use in children less than 2 years of age due to the risk of marked sedation and respiratory depression.

Patients are strongly advised not to consume alcoholic beverages or medicines containing alcohol throughout treatment (see section 4.5).

Exposure to sunlight should be avoided during treatment (see section 4.8).

There is a risk of post-operative restlessness especially if the child is in pain.

Tablets contains lactose:

Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.

This medicine contains less than 1 mmol sodium (23 mg) per dose, that is to say essentially 'sodium-free'.

4.5. Interaction with other medicinal products and other forms of interaction

The sedative effects of phenothiazines may be intensified (additively) by alcohol (see section 4.4), anxiolytics & hypnotics, opiates, barbiturates and other sedatives. There may be increased antimuscarinic and sedative effects of phenothiazines with tricyclic antidepressants & MAOI's (including moclobemide). Respiratory depression may occur.

The hypotensive effect of most antihypertensive drugs especially alpha adrenoreceptor blocking agents may be exaggerated by phenothiazines. The use of antimuscarinics will increase the risk of antimuscarinic side effects when in conjunction with antihistamines.

The mild anticholinergic effect of phenothiazines may be enhanced by other anticholinergic drugs possibly leading to constipation, heat stroke, etc.

The action of some drugs may be opposed by phenothiazines; these include amphetamine, levodopa, clonidine, guanethidine, and adrenaline.

Anticholinergic agents may reduce the antipsychotic effect of phenothiazines.

Some drugs interfere with absorption of phenothiazines: antacids, anti-Parkinson, and lithium. Increases or decreases in the plasma concentrations of a number of drugs, e.g. propranolol and phenobarbital have been observed but were not of clinical significance.

High doses of phenothiazines reduce the response to hypoglycaemic agents, the dosage of which may have to be raised. Adrenaline must not be used in patients overdosed with phenothiazines.

As with other neuroleptic phenothiazines, caution is advised with concomitant use of QT prolonging drugs or drugs that cause electrolyte imbalance.

4.6. Fertility, pregnancy and lactation

Pregnancy

There is inadequate evidence of the safety of Alimemazine in human pregnancy, but it has been widely used for many years without apparent ill consequence. Some phenothiazines have shown evidence of harmful effects in animals. Alimemazine, like other drugs, should be avoided in pregnancy unless the physician considers it essential. Neuroleptics may occasionally prolong labour and at such a time should be withheld until the cervix is dilated 3-4cm. Possible adverse effects on the neonate include lethargy or paradoxical hyper excitability, tremor and low Apgar score.

Breast-feeding

Phenothiazines may be excreted in milk: breast feeding should be suspended during treatment.

4.7. Effects on ability to drive and use machines

Patients should be warned about drowsiness during the early days of treatment, and advised not to drive or operate machinery.

4.8. Undesirable effects

The following adverse reactions are classified by system organ class and ranked under heading of frequency using the following convention:

Not known (cannot be estimated from the available data).

Blood and lymphatic system disorders:

• A mild leukopenia occurs in up to 30% of patients on prolonged high dosage.

• Agranulocytosis may occur rarely; it is not dose related.

The occurrence of unexplained infections or fever requires immediate haematological investigation.

Psychiatric disorders:

• Insomnia

• Agitation.

Nervous system disorders:

• Drowsiness or sedation, more marked at the start of treatment.

• Convulsions have been reported in some patients.

• Extrapyramidal: Acute dystonias or dyskinesias, usually transitory are commoner in children and young adults and usually occur within the first 4 days of treatment or after dosage increases.

- Akathisia characteristically occurs after large doses.

- Parkinsonism is commoner in adults and the elderly. It usually develops after weeks or months of treatment. One or more of the following may be seen: tremor, rigidity, akinesia or other features of Parkinsonism. Commonly just tremor.

- Tardive dyskinesia: If this occurs it is usually, but not necessarily, after prolonged or high dosage. It can even occur after treatment has been stopped. Dosage should therefore be kept low whenever possible.

Eye disorders:

• Accommodation disorders

Cardiac disorders:

Cardiac arrhythmias, including atrial arrhythmia: A-V block, ventricular tachycardia and fibrillation have been reported during therapy, possibly related to dosage. Pre-existing cardiac disease, old age, hypokalaemia and concurrent tricyclic antidepressants may predispose.

Vascular disorder

• Hypotension, or pallor may occur in children.

• Elderly or volume depleted subjects are particularly susceptible to postural hypotension (see section 4.4).

Respiratory, thoracic and mediastinal disorders:

• Nasal stuffiness

• Respiratory depression is possible in susceptible patients.

Gastrointestinal disorders:

• Dry mouth

• Constipation

Hepatobiliary disorders:

Jaundice, usually transient, occurs in a very small percentage of patients. A premonitory sign may be a sudden onset of fever after one to three weeks of treatment followed by the development of jaundice. Neuroleptic jaundice has the biochemical and other characteristics of obstructive jaundice and is associated with obstructions of the canaliculi by bile thrombi; the frequent presence of an accompanying eosinophilia indicates the allergic nature of this phenomenon. Treatment should be withheld on the development of jaundice.

Skin and subcutaneous tissue disorders:

• Contact skin sensitisation is a serious but rare complication in those frequently handling preparations of phenothiazines: Care must be taken to avoid contact of the drug with the skin.

• Skin rashes of various kinds may also be seen in patients treated with the drug.

• Patients on high dosage may develop photosensitivity in sunny weather and should avoid exposure to direct sunlight (see section 4.4). Ocular changes and the development of a metallic greyish-mauve colouration of exposed skin have been noted in some individuals, mainly females, who have received chlorpromazine continuously for long periods (four to eight years).

Renal and urinary disorders:

• Urinary retention

Endocrine disorders:

• Hyperprolactinaemia which may result in galactorrhoea, gynaecomastia, amenorrhoea and impotence.

• Neuroleptic malignant syndrome (hyperthermia, rigidity, autonomic dysfunction and altered consciousness) may occur.

General disorders and administration site conditions:

• Paradoxical excitement has been noted.

Investigations:

ECG changes, usually benign, including:

• Widened QT interval, ST segment depression, U-waves and T-wave changes.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

4.9. Overdose

Symptoms

Symptoms of phenothiazine overdosage include drowsiness or loss of consciousness, hypotension, tachycardia, ECG changes, ventricular arrhythmias and hypothermia. Severe extra-pyramidal dyskinesias may occur.

Treatment

If the patient is seen sufficiently soon (up to 6 hours) after ingestion of a toxic dose, gastric lavage may be attempted. Pharmacological induction of emesis is unlikely to be of any use. Activated charcoal should be given. There is no specific antidote. Treatment is supportive.

Generalised vasodilatation may result in circulatory collapse; Raising the patient's legs may suffice, in severe cases, volume expansion by intravenous fluids may be needed; infusion fluids should be warmed before administration in order not to aggravate hypothermia.

Positive inotropic agents such as dopamine may be tried if fluid replacement is insufficient to correct the circulatory collapse. Peripheral vasoconstrictor agents are not generally recommended; avoid the use of adrenaline.

Ventricular or supraventricular tachy-arrhythmias usually respond to restoration of normal body temperature and correction of circulatory or metabolic disturbances. If persistent or life-threatening, appropriate anti-arrhythmic therapy may be considered. Avoid lidocaine and, as far as possible, long acting anti-arrhythmic drugs.

Pronounced central nervous system depression requires airway maintenance or, in extreme circumstances, assisted respiration. Severe dystonic reactions, usually respond to procyclidine (5-10mg) or orphenadrine (20-40mg) administered intramuscularly or intravenously. Convulsions should be treated with intravenous diazepam.

Neuroleptic malignant syndrome (NMS) has been reported in the context of alimemazine overdose. Symptoms of NMS include a combination of hyperthermia, muscle rigidity, altered mental status and autonomic instability. Since this syndrome is potentially fatal, alimemazine must be discontinued immediately, and intensive clinical monitoring and symptomatic treatment must be initiated.

Strict adherence to the recommended dose is critical (see also section 4.2)

Neuroleptic malignant syndrome should be treated with cooling. Dantrolene sodium may be tried.