suxamethonium chloride: clinical use

Prescribing considerations

• Administer only during adequate anaesthesia by, or under close supervision of, an anaesthetist able to intubate and provide positive-pressure ventilation.
• Review potassium risk, neuromuscular disease, immobility, burns, major trauma, denervation, severe sepsis and reduced plasma cholinesterase activity.
• Previous suspected peri-anaesthetic hypersensitivity warrants appropriate investigation because cross-sensitivity between neuromuscular blockers can occur.
• Use particular care in children because occult neuromuscular disease and bradycardia increase risk.
• Advanced myasthenia gravis, myasthenic syndromes, open eye injury and glaucoma require careful benefit–risk assessment.

Contraindications and cautions

• Hypersensitivity to suxamethonium chloride or an excipient
• Patient not fully anaesthetised
• Personal or family history of malignant hyperthermia
• Inherited atypical or abnormal plasma cholinesterase activity
• Hyperkalaemia from any cause
• Muscular dystrophy or another relevant myopathy
• Personal or family history of congenital myotonic disease

Monitoring

• Maintain continuous airway, ventilation and cardiovascular monitoring.
• Assess neuromuscular function during infusion or substantial cumulative exposure.
• Consider potassium status where hyperkalaemia risk factors are present.
• Watch for anaphylaxis, bradycardia, arrhythmia, prolonged apnoea, muscle breakdown and malignant hyperthermia.
• If paralysis is unexpectedly prolonged, continue ventilatory support until spontaneous recovery and investigate plasma cholinesterase activity when appropriate.

Clinical pharmacology

Suxamethonium is an acetylcholine-receptor agonist that produces a phase I depolarising block at the skeletal neuromuscular junction. It is rapidly hydrolysed by plasma cholinesterase; reduced enzyme activity can markedly prolong blockade. Repeated or prolonged exposure may produce a phase II block.

Formulation and product differences

• The selected product is a clear, colourless solution for intravenous injection or infusion in a single-use glass ampoule.
• It requires refrigerated storage, protection from light and immediate use after opening.
• The acidic solution must not be mixed with highly alkaline preparations such as barbiturates, or placed in the same syringe as another agent.

Injection

Route: Parenteral

Strengths: 50 mg/mL