On this page
- Sedating H1 antihistamine
- Agitation or aggressive behaviour in patients with acute or chronic psychosis, in combination with haloperidol
Forms and strengths, route of administration
- 50 mg in 2 ml ampoule (25 mg/ml) for deep IM injection.
- NEVER ADMINISTER BY SC INJECTION.
Dosage and duration
- Adult: 25 mg, to be repeated after 30 minutes if necessary. If no response 30 minutes after the second dose, administer 50 mg (total dose max. 100 mg).
Contra-indications, adverse effects, precautions
- Administer with caution and monitor use:
- in older patients;
- in patients with prostate disorders, closed-angle glaucoma, epilepsy, orthostatic hypotension, severe renal or hepatic impairment;
- in patients taking central nervous system depressants (opioid analgesics, antipsychotics, sedatives, antidepressants, etc.) or drugs known to have an anticholinergic effect (atropine, amitriptyline, chlorpromazine, etc.).
- May cause:
- drowsiness, dizziness, headache, confusional state, hypotension, photosensitivity (protect skin from sun exposure);
- anticholinergic effects (dry mouth, constipation, blurred vision, tachycardia, disorders of micturition);
- tissue damage, including necrosis;
- rarely: seizures, extrapyramidal syndrome, neuroleptic malignant syndrome (unexplained hyperthermia with neuromuscular disorders), allergic reactions.
- Pregnancy and breast-feeding: avoid
- Promethazine is not included in the WHO list of essential medicines.
– Below 25 °C