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    Last updated: February 2024


    Prescription under medical supervision


    Therapeutic action

    • Sedating H1 antihistamine


    • Insomnia
    • Agitation or aggressive behaviour in patients with acute or chronic psychosis, in combination with haloperidol

    Forms and strengths

    • 25 mg tablet

    Dosage and duration


    • Adult: 25 mg once daily at bedtime for 7 to 10 days max. 


    Agitation or aggressive behaviour in patients with acute or chronic psychosis, with haloperidol 

    • Adult: 25 mg, to be repeated after 60 minutes if necessary 

    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 (caution when driving/operating machinery), dizziness, headache, confusional state, hypotension, photosensitivity (protect skin from sun exposure); 
      • anticholinergic effects (dry mouth, constipation, blurred vision, tachycardia, disorders of micturition);
      • rarely: seizures, extrapyramidal symptoms, neuroleptic malignant syndrome (unexplained hyperthermia with neuromuscular disorders), allergic reactions.
    • Avoid alcohol during treatment (increased risk of adverse effects).
    • Pregnancy and breast-feeding: avoid


    • Promethazine is not included in the WHO list of essential medicines. 


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