Adult: As short-term adjunctive management: 100-200 mg 4 times daily.
Oral Agitation, Restlessness
Elderly: 25-50 mg 4 times daily.
Contraindications
Severe CNS depression, comatose states, phaeochromocytoma; bone marrow depression (syrup). Pregnancy and lactation.
Special Precautions
Patient with history of blood dyscrasias, jaundice; CV disease (e.g. QT prolongation, significant bradycardia [<50 bpm], recent MI, decompensated heart failure, arrhythmias), increased risk for arrhythmias (e.g. hypokalaemia, hypomagnesaemia, genetic predisposition); cerebral arteriosclerosis or any condition in which a fall in blood pressure might be undesirable; risk factors for stroke and VTE; Lewy body dementia or Parkinson's disease dementia; myasthenia gravis, Parkinson's disease, depression; personal or a family history of narrow angle glaucoma; history of or at risk of seizures; prostatic hyperplasia; severe respiratory disease; hypothyroidism. Not approved for the treatment of dementia-related behavioural disturbances. Avoid abrupt withdrawal. Renal and hepatic impairment. Elderly.
Adverse Reactions
Significant: CNS depression, extrapyramidal symptoms (e.g. pseudoparkinsonism, dystonia, akathisia, dyskinesia), QT interval prolongation, significant hypotension, hyperprolactinaemia, photosensitivity, impaired body temperature regulation, increased risk of VTE; ocular effects (e.g. pigmentary changes or lenticular and corneal deposits), particularly with prolonged use. Blood and lymphatic system disorders: Agranulocytosis, leucopenia, haemolytic anaemia. Cardiac disorders: Tachycardia. Eye disorders: Blurred vision, precipitation of glaucoma. Gastrointestinal disorders: Gastrointestinal disturbances, dry mouth, constipation. General disorders and administration site conditions: Hypothermia, hyperpyrexia. Investigations: ECG changes, transient abnormal LFTs, weight gain. Nervous system disorders: Drowsiness, dizziness, headache, sedation, epilepsy, NMS. Psychiatric disorders: Apathy, confusional state. Reproductive system and breast disorders: Menstrual disturbances, galactorrhoea, gynaecomastia, impotence. Respiratory, thoracic and mediastinal disorders: Nasal congestion. Skin and subcutaneous tissue disorders: Sensitivity reactions (e.g. allergic skin reactions, rashes, contact sensitisation).
Patient Counseling Information
Avoid exposure to sunlight; wear protective clothing and use sunscreen. This drug may cause drowsiness and impair alertness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor liver function, ECG (prolonged use), CBC (prolonged use or in case of unexplained fever or infection). Assess for extrapyramidal symptoms, including tardive dyskinesia (particularly at high doses or in elderly) and ophthalmic changes.
Overdosage
Symptoms: Drowsiness, confusion, hypotension, hypothermia, convulsions, and coma. Rarely, respiratory depression, rhabdomyolysis, renal failure, and cardiac effects (e.g. sinus tachycardia, QT and QRS prolongation, ventricular tachycardia, ventricular fibrillation, AV block, bundle branch block, torsades de pointes). Management: Symptomatic and supportive treatment. Administer activated charcoal or perform gastric lavage within 1 hour of ingestion. Maintain a clear airway and adequate ventilation. Observe asymptomatic patients for at least 4 hours after ingestion and monitor pulse and blood pressure. Perform ECG and monitor cardiac rhythm in symptomatic patients. May administer inotropes (e.g. dopamine or dobutamine) in case of severe hypotension. Correct acid-base balance, metabolic disturbances, and hypothermia. Convulsions may respond to IV diazepam or lorazepam; phenytoin may be considered if still unresponsive to initial therapy. Persistent seizures may require intubation, paralysis, and ventilation.
Drug Interactions
Increased risk of ventricular arrhythmias, including torsades de pointes with QT-prolonging drugs (e.g. quinidine, disopyramide, amiodarone, sotalol, moxifloxacin, IV erythromycin, maprotiline, amitriptyline, pimozide, terfenadine, quinine, cisapride). May impair the therapeutic effects of anticonvulsants. Enhanced hypotensive effects with antihypertensives and anaesthetics. May increase plasma concentration with ritonavir. Increased risk of extrapyramidal effects with tetrabenazine and metoclopramide. Enhanced sedative effects with anxiolytics and hypnotic drugs. Concomitant use with lithium may increase the risk of extrapyramidal effects and the possibility of neurotoxicity. Enhanced anticholinergic effects with antiparkinsonian or other anticholinergic drugs. May enhance the therapeutic effect with cimetidine. Increased risk of CNS toxicity with sibutramine. May reduce the therapeutic effect with memantine. Increased plasma concentrations and increased antimuscarinic effects with TCAs.
Food Interaction
Enhanced sedative effect with alcohol.
Action
Description: Mechanism of Action: Promazine is a phenothiazine that inhibits the dopaminergic receptors in the medullary chemoreceptor trigger zone, blocks the postsynaptic mesolimbic dopaminergic receptors in the brain, and peripherally blocks the vagus nerve of the gastrointestinal tract. It also exhibits anticholinergic and antihistamine effects, blocks α-adrenergic receptors, and reduces the release of hypothalamic and hypophyseal hormones. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Distribution: Distributed in the brain, lungs, and other tissues with a high blood supply. Plasma protein binding: 90%. Metabolism: Extensively metabolised in the liver mainly via conjugation with glucuronic acid; undergoes first-pass metabolism in the gut wall. Excretion: Via urine (mainly as hydrophilic metabolites); bile. Elimination half-life: 20-40 hours.
Chemical Structure
Promazine Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4926, Promazine. https://pubchem.ncbi.nlm.nih.gov/compound/Promazine. Accessed Aug. 27, 2025.
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