levomepromazine hydrochloride: clinical use

Prescribing considerations

• Assess susceptibility to sedation, postural hypotension, anticholinergic effects, falls and extrapyramidal reactions, particularly in older or debilitated people.
• Review cardiac disease, QT-prolonging medicines, electrolyte disturbance and other arrhythmia risk factors.
• Assess venous-thromboembolism and stroke risks; selected products are not indicated for dementia-related behavioural disturbance.
• Use particular caution with epilepsy, Parkinson's disease, glaucoma, urinary retention, prostatic enlargement, constipation, diabetes and renal or hepatic impairment.
• Avoid abrupt withdrawal after prolonged treatment where clinically feasible.

Contraindications and cautions

• Hypersensitivity to levomepromazine or relevant formulation ingredients; the oral solution additionally lists phenothiazine or thioxanthene hypersensitivity.
• The oral solution should not be used during acute intoxication with alcohol, hypnotics, analgesics or psychotropic medicines, or in shock, coma or haematopoietic impairment.
• Citalopram, escitalopram, hydroxyzine, piperaquine and domperidone are contraindicated with the selected Nozinan injection.
• The oral solution is not recommended for children or adolescents under 16 years.

Monitoring

• Consider ECG and calcium, magnesium and potassium assessment where clinically appropriate.
• Monitor blood pressure, sedation, falls, bowel and urinary function, movement symptoms and temperature regulation.
• Check blood glucose in people with diabetes or risk factors.
• Obtain a full blood count promptly for persistent fever, sore throat or infection.
• Consider liver and renal function, particularly with impairment or use of the propylene-glycol-containing oral solution.

Clinical pharmacology

A phenothiazine antagonist at dopamine, serotonin, histamine, alpha-adrenergic and muscarinic receptors. Extensive first-pass metabolism reduces oral bioavailability. Hepatic metabolism includes CYP3A4 pathways, and levomepromazine inhibits CYP2D6.

Formulation and product differences

• The oral solution includes a graduated oral syringe and bottle adapter. It contains propylene glycol, sodium benzoate and benzyl alcohol and should be used within three months of opening.
• The injection may be administered intramuscularly, intravenously after appropriate dilution, or by continuous subcutaneous infusion by healthcare professionals.
• The injection contains sulphite, which may rarely cause severe hypersensitivity or bronchospasm, and is incompatible with alkaline solutions.
• Licensed indications differ between the oral solution and injection.

Oral solution

Route: Oral

Strengths: 5 mg/mL

Injection

Route: Parenteral

Strengths: 25 mg/mL