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Paracetamol Overdose — RACP Adult Medicine MCQ

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EasyClinical PharmacologyParacetamol OverdoseRACP Adult Medicine

A 45-year-old man accidentally ingests an unknown quantity of paracetamol. He presents 6 hours post-ingestion with nausea but is otherwise well. His serum paracetamol level at 6 hours is 180 mg/L (reference: above modified Rumack-Matthew nomogram treatment line). What is the most appropriate management?

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Correct answer: E — IV N-acetylcysteine (NAC)

When the paracetamol level is above the treatment line on the modified Rumack-Matthew nomogram, IV NAC should be commenced immediately. The Australian two-bag NAC protocol (200 mg/kg over 2 hours loading, then 100 mg/kg over 22 hours) is increasingly used, replacing the traditional three-bag protocol. Activated charcoal is only beneficial within 1–2 hours of ingestion. NAC is most effective when commenced within 8 hours of ingestion.

Reference: eTG – 2025 – Toxicology; Austin Health Toxicology – 2024 – Modified 2-Bag NAC Protocol