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Suxamethonium IOP Increase — FRCA Primary MCQ

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HardPharmacology - NeuromuscularSuxamethonium IOP IncreaseFRCA Primary

After thiopental and suxamethonium for rapid-sequence induction, when is the drug-related intraocular-pressure increase most likely to be greatest?

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Correct answer: B — Two to four minutes after suxamethonium administration

The best answer is “Two to four minutes after suxamethonium administration”. Suxamethonium causes a transient rise in intraocular pressure that peaks around two to four minutes and usually returns towards baseline within several minutes. The increase matters when timing airway manipulation in an open-globe context, though the overall anaesthetic risk–benefit decision is clinical. The other timings do not match its brief pharmacodynamic effect.

Reference: RCoA, Primary FRCA syllabus: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf; Intraocular pressure: physiology and implications for anaesthetic management: https://pubmed.ncbi.nlm.nih.gov/3516335/