promazine hydrochloride: clinical use

Prescribing considerations

• Use only as an adjunct to non-pharmacological management for the selected licensed indication.
• Assess cardiac disease, QT risk, electrolytes, seizure risk, hepatic and renal function, Parkinsonism, glaucoma, prostatic enlargement, respiratory disease and venous-thromboembolism risk.
• Older people are especially susceptible to sedation, hypotension and impaired temperature regulation.
• Avoid abrupt discontinuation after ongoing treatment because withdrawal and movement disorders can occur.
• Consider high variability in systemic exposure and review effectiveness and toxicity.

Contraindications and cautions

• Hypersensitivity to promazine, other phenothiazines or relevant excipients
• Coma or central nervous system depression
• Bone-marrow depression
• Phaeochromocytoma
• Moderate or severe hepatic impairment
• Long-QT syndrome
• Pregnancy unless compelling reasons exist
• Breastfeeding

Monitoring

• Clinical response, sedation, postural blood pressure and falls risk
• Movement disorders, including akathisia, dystonia and tardive dyskinesia
• ECG and electrolytes when cardiac or QT risk factors are present
• Blood count if unexplained infection, fever or sore throat occurs
• Liver function and signs of jaundice
• During prolonged use, blood, cardiac-conduction and ocular effects
• Weight, metabolic effects, prolactin-related effects and venous-thromboembolism risk as clinically appropriate

Clinical pharmacology

Promazine is an aliphatic phenothiazine dopamine inhibitor with central depressant, alpha-adrenergic blocking and weaker anticholinergic activity. Oral absorption is followed by substantial first-pass and hepatic metabolism, extensive protein binding and wide interpatient variability in plasma exposure.

Formulation and product differences

• The selected preparation is an oral syrup requiring accurate volume measurement.
• It contains glucose, sucrose, propylene glycol, parabens and a small amount of ethanol; these excipients may matter in diabetes, sugar intolerance, renal or hepatic impairment, allergy risk and dental care.
• Store in the original bottle protected from light and observe the stated in-use shelf life.

Syrup

Route: Oral

Strengths: 25 mg/5 mL, 50 mg/5 mL