Promazine hydrochloride

How it works

It blocks central dopamine D2 receptors and also antagonises histamine, muscarinic and alpha-adrenergic receptors, giving it strong sedative and autonomic effects relative to its antipsychotic potency.

Prescribing in practice

• Sedation and postural hypotension are prominent, increasing the risk of falls in elderly patients who should be treated cautiously.
• Antipsychotics are associated with an increased risk of stroke and mortality when used for behavioural symptoms in elderly people with dementia.
• It carries the class risks of QT prolongation, extrapyramidal effects and neuroleptic malignant syndrome, with caution needed in cardiovascular and hepatic disease.

Monitoring

Monitor sedation, postural blood pressure, fall risk and for extrapyramidal or neuroleptic malignant features during treatment.

Counselling the patient

• This medicine is likely to make you drowsy; do not drive or use machinery until you know how it affects you.
• Get up slowly from sitting or lying to reduce dizziness.
• Avoid alcohol, which increases drowsiness.

Evidence & guidelines

Caution with antipsychotics in elderly and dementia patients is highlighted by MHRA and NICE guidance on increased stroke and mortality risk.