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Acetaminophen overdose — MCCQE Part 1 MCQ

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HardPoisoning/OverdoseAcetaminophen overdoseMCCQE Part 1

A 19-year-old woman presents 10 hours after taking an unknown number of acetaminophen tablets. She is nauseated, ALT is normal, and acetaminophen level will not return for 3 hours. The time of ingestion is uncertain because she vomited and slept. What is the most appropriate next step in management?

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Correct answer: B — Start N-acetylcysteine while awaiting levels

When acetaminophen ingestion time or dose is uncertain and potentially toxic, N-acetylcysteine should be started while levels are pending. Early ALT may be normal despite impending toxicity. Activated charcoal may help early after ingestion but is not definitive at 10 hours. Flumazenil is irrelevant.

Reference: Canadian poison centre acetaminophen guidance