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Acetaminophen overdose — RCPSC EM MCQ

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ModerateToxicologyAcetaminophen overdoseRCPSC EM

A 23-year-old woman presents CTAS 2 four hours after ingesting an unknown number of extended-release acetaminophen tablets. She is nauseated but alert; BP is 118/72 and HR 94. The acetaminophen level is not yet available and the laboratory reports a likely delay. What is the most appropriate next step?

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Correct answer: B — Start N-acetylcysteine while awaiting the acetaminophen concentration

When a potentially toxic acetaminophen ingestion is near or beyond 4 hours and levels are delayed, NAC should be started early because benefit is time-sensitive and initial transaminases may be normal.

Reference: Poison centre toxicology guidance; Goldfrank-style ED toxicology principles