HISTERZIN

PROMETHAZINE HYDROCHLORIDE

Potent long-acting antihistamine with additional anti-emetic and sedative/calming effects. Indicated in symptomatic treatment of allergic conditions of the respiratory tract and skin. Sensitization reactions to drug or foreign proteins, anaphylactic reactions. For sedation, allergic rhinitis, urticaria and insomnia. As an adjunct in pre-operative sedation in surgery and obstetrics. As a paediatric sedative

Anti-emetic drugs, Miscellaneous sedatives & hypnotics, Sedating Anti-histamine

Promethazine is a phenothiazine derivative which blocks postsynaptic mesolimbic dopaminergic receptors in the brain. It exhibits strong 8-adrenergic blocking effect and depresses the release of hypothalamic and hypophyseal hormones. It competes with histamine for the H1-receptor; muscarinic blocking effect may be responsible for antiemetic activity. It also reduces stimuli to the brainstem reticular system. Promethazine is well absorbed from the gastrointestinal tract. Clinical effects are apparent within 20 minutes after oral administration and generally last four to six hours, although they may persist as long as 12 hours. Promethazine is metabolized by the liver to a variety of compounds; the sulfoxides of promethazine and N-demethylpromethazine are the predominant metabolites appearing in the urine.

Adults: Initial dose one 25 mg tablet at night; may be increased to two or three 25 mg tablets at night if necessary. In allergic conditions more frequently administration, twice or three times daily, may be necessary, starting with one or two 10 mg tablets and increasing as required. Elderly: No specific dosage recommendations. Children: They may be treated more conveniently by the elixir containing 5 mg/5 ml. As an antihistamine in allergy: Children of 2-5 years: 5-15 mg Children of 5-10 years: 10-25 mg In case where two doses in 24 hours are required the lower dose stated should be given. As a sedative: Children of 2-5 years: 15-20 mg Children of 5-10 years: 20-25 mg Given as a single night-time dose

Promethazine Hydrochloride may enhance the action of any anticholinergic agent, tricyclic antidepressant, sedative or hypnotic, Alcohol should be avoided during drug treatment. Phenergan may interfere with immunologic urine pregnancy tests to produce false-positive or false-negative results. Phenergan should be discontinued at least 72 hours before the start of skin tests using allergen extracts as it may inhibit the cutaneous histamine response thus producing false-negative results.

Promethazine is contraindicated for use in children less than two years of age Hypersensitivity to promethazine or to any of the excipients. Phenergan should not be used in patients who are in a coma or suffering from CNS depression of any cause. It must not be given to neonates or premature infants. Phenergan should be avoided in patients who have been taking monoamine oxidase inhibitors within the previous 14 days

Nervous system disorders: Frequency Unknown: Neuroleptic Malignant Syndrome Very rare cases of allergic reactions, including urticaria, rash, pruritus, and anaphylaxis, have been reported. For systemic formulations only: A very serious and sometimes deadly health problem called neuroleptic malignant syndrome (NMS) may happen. Stop treatment and call your doctor right away if you have high fever, muscle cramps or stiffness, dizziness, very bad headache, fast heartbeat, confusion, agitation, hallucinations, or are sweating a lot. For systemic formulations only: Use this drug only as recommended. Do not exceed the recommended dose. There have been case reports of promethazine abuse. Do not take for longer than 10 days.

There is epidemiological evidence for the safety of promethazine in pregnancy and animal studies have shown no hazard, nevertheless, it should not be used in pregnancy unless the physician considers it essential. The use of Phenergan is not recommended in the two weeks prior to delivery in view of the risk of irritability and excitement in the neonate. Available evidence suggests that the amount excreted in milk is insignificant. However there are risks of neonatal irritability and excitement.

Symptoms of severe over dosage are variable. They are characterised in children by various combinations of excitation, ataxia, incoordination, athetosis and hallucinations, while adults may become drowsy and lapse into coma. Convulsions may occur in both adults and children; coma or excitement may precede their occurrence. Cardiorespiratory depression is uncommon. If the patient is seen soon enough after ingestion, it should be possible to induce vomiting with ipecacuanha despite the antiemetic effect of promethazine; alternatively, gastric lavage may be used. Treatment is otherwise supportive with attention to maintenance of adequate respiratory and circulatory status. Convulsions should be treated with diazepam or other suitable anticonvulsant

The use of promethazine should be avoided in children and adolescents with signs and symptoms suggestive of Reye8s syndrome.

Protect from light. Do not use later than the date of expiry. Keep all medicines out of the reach of children. To be dispensed only on the prescription of a registered physician