Paracetamol overdose risk — ORE Part 1 MCQ

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HardDental Pharmacology and TherapeuticsParacetamol overdose riskORE Part 1

A 44-year-old man with severe dental pain has taken two 500 mg paracetamol tablets every 2 hours for the last 24 hours. He has also taken a proprietary cold remedy containing paracetamol. He weighs 58 kg, has eaten very little for 2 days, and now reports nausea and right upper-quadrant abdominal discomfort. What is the most likely explanation?

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Correct answer: B — Paracetamol-related hepatotoxicity

Explanation lettering: E = shown as A · A = shown as B · B = shown as C · C = shown as E

A is correct. He has taken about 12 g of paracetamol in 24 hours before counting the cold remedy: approximately 207 mg/kg/day at 58 kg. This greatly exceeds both the licensed maximum of 4 g/day and SDCEP’s threshold for emergency assessment following therapeutic excess. Concurrent paracetamol-containing preparations and poor intake increase concern; starvation is a recognised glutathione-depleting risk factor. Nausea and abdominal pain are compatible with early paracetamol toxicity, although serious liver injury can initially be clinically subtle. B is impossible because paracetamol is not an opioid. C requires aspirin/NSAID sensitivity and bronchospasm, neither of which is present. D requires relevant local-anaesthetic exposure and typically causes cyanosis or hypoxia. E requires metronidazole with alcohol exposure.

Reference: Scottish Dental Clinical Effectiveness Programme. Management of Acute Dental Problems: Analgesia, 2026. https://www.acutedentalproblems.sdcep.org.uk/supporting-tools/analgesia/