PONV Rescue Antiemetic — FRCA Final MCQ

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ModerateDay SurgeryPONV Rescue AntiemeticFRCA Final

A 45-year-old woman (ASA II) undergoes arthroscopic knee surgery under general anaesthesia. Post-operatively she vomits three times in recovery despite ondansetron 4 mg IV. Which antiemetic with a different mechanism of action should be given next?

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Correct answer: C — Cyclizine 50 mg IV

After failure of a 5-HT3 antagonist (ondansetron), an antiemetic from a different class should be used. Cyclizine (H1 antihistamine) acts at a different receptor and provides complementary antiemetic effect. The combination approach to PONV uses agents from different classes: 5-HT3 antagonists, corticosteroids, dopamine antagonists, antihistamines, and NK-1 antagonists. Dexamethasone is effective but works best as prophylaxis given at induction. Repeating ondansetron within 6-8 hours is unlikely to add benefit. Apfel score risk factors determine baseline risk.

Reference: Association of Anaesthetists – 2020 – PONV guidelines; RCOA – 2023 – Day surgery module