Suxamethonium Side Effects — FRCA Primary MCQ
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Correct answer: A — Decreased intraocular pressure
The correct answer is A. Suxamethonium causes a transient increase, not decrease, in intraocular pressure, so decreased intraocular pressure is not a recognised adverse effect. Depolarisation of skeletal muscle also produces potassium efflux; the rise is usually modest in healthy patients but may cause severe hyperkalaemia in susceptible states. Bradycardia is recognised, particularly in children and after repeated doses, reflecting autonomic and muscarinic effects. Suxamethonium is a recognised trigger of malignant hyperthermia in genetically susceptible patients. Masseter spasm, also described as trismus or masseter muscle rigidity, may occur and can be associated with susceptibility to malignant hyperthermia, although isolated spasm is not diagnostic of it.
Reference: electronic Medicines Compendium, Suxamethonium Chloride 50 mg/ml Solution for Injection, SmPC sections 4.3, 4.4 and 4.8, updated 25 September 2023. https://www.medicines.org.uk/emc/product/5189/smpc