clonazepam: clinical use

Prescribing considerations

• Confirm the product-specific licensed age range and indication; selected oral solutions are adult-only because they contain ethanol, while the selected injection is for adults and adolescents from 12 years.
• Assess respiratory disease, hepatic or renal impairment, frailty, falls risk, CNS depressants, substance misuse history and suicide risk.
• Tolerance, physical dependence and withdrawal can occur. Avoid abrupt discontinuation, particularly in epilepsy.
• Concurrent opioids carry a substantial risk of sedation and respiratory depression.
• Consider lactose in selected tablets and ethanol in Rosemont oral solutions.

Contraindications and cautions

• Hypersensitivity to clonazepam, another benzodiazepine or a formulation excipient
• Acute pulmonary insufficiency or severe respiratory insufficiency
• Sleep apnoea syndrome
• Myasthenia gravis
• Severe hepatic insufficiency
• Coma or known misuse of medicines, drugs or alcohol; exact wording varies by product
• The selected injectable product is contraindicated below 12 years

Monitoring

• Seizure control and emergence of breakthrough or status seizures
• Sedation, cognition, coordination, falls and ability to undertake safety-critical tasks
• Respiratory status, especially with pulmonary disease, opioids or other CNS depressants
• Mood, behavioural change and suicidal ideation
• Signs of tolerance, misuse, dependence or withdrawal
• Liver function or blood count when clinically indicated
• Breastfed infants for drowsiness, slow breathing, feeding and weight gain
• Routine plasma concentration monitoring has unproven value because concentrations correlate poorly with response and adverse effects

Clinical pharmacology

Clonazepam is a long-acting benzodiazepine antiepileptic with anticonvulsant, sedative, anxiolytic and muscle-relaxant properties. Oral bioavailability is high, hepatic metabolism involves CYP3A4, and the elimination half-life is prolonged.

Formulation and product differences

• Selected tablets contain lactose; score-line design and divisibility are product-specific.
• Rosemont oral solutions are oily, contain ethanol and come with a graduated measuring spoon. They are incompatible with PVC and polystyrene and require specific enteral-tube handling.
• The lower-concentration Rosemont solution supports measurement of smaller prescribed quantities.
• The injectable concentrate requires appropriate dilution and administration by healthcare professionals. It contains ethanol, benzyl alcohol and propylene glycol.

Oral solution

Route: Oral

Strengths: 0.5 mg/5 mL, 2 mg/5 mL

Tablet

Route: Oral

Strengths: 0.5 mg, 1 mg, 2 mg