Acetaminophen OverdoseUrgent

Emergency / Toxicology · Ward Pathways · Free — no sign-in

Nausea early → hepatic failure late

ABCDE

Assess airway if drowsy; timed level; start NAC per protocol; bloods (INR/LFT/gas).

Calculators:
  1. Level at 4 h → plot on Rumack-Matthew nomogram
  2. Treat: N-acetylcysteine (NAC) + activated charcoal — do NOT wait for the level if presentation is late/large

Order set

  • Paracetamol level at 4 h
  • LFTs, INR, U&E, VBG
  • Rumack-Matthew nomogram
  • NAC per protocol

Criteria

AdmitTreatment-line level or staggered/late ingestion
ICUHepatic failure / encephalopathy
DischargeNAC complete, LFTs/INR improving, criteria not met, psych review
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
  • Encephalopathy
  • Rising INR/lactate (King's criteria)
Differentials
  • Co-ingestants
  • Other hepatotoxins
Common mistakes
  • Waiting for level in late/staggered ingestion
  • Stopping NAC too early
  • Massive ingestion (>500 mg/kg or level >300 mg/L) — discuss augmented-dose NAC + consider hemodialysis (EXTRIP 2024 acetaminophen workgroup)
Disposition & follow-up

NAC; liver unit referral if criteria met.

Discharge package
Medications—
Follow-upPsychiatry review; hepatology if LFT/INR abnormal
Warning symptomsVomiting, jaundice, confusion
💊 Treatment detail — doses & preparation
N-acetylcysteine (NAC)paracetamol antidote
Dose150 mg/kg in 200 mL D5W over 1 h → 50 mg/kg in 500 mL over 4 h → 100 mg/kg in 1 L over 16 h (150/50/100 protocol); continue if still acidotic/INR rising
Preparation200 mg/mL ampoules — dilute in D5W as above; weight-capped at 110 kg
MonitorAnaphylactoid reactions (flush/wheeze — slow/stop, antihistamine, restart slower); INR, glucose
Dextrose 10% infusionhypoglycaemia/ALF
Dose100–200 mL/h of 10% titrated to glucose 5–8 mmol/L
Preparation500 mL/1 L bags; give with thiamine in at-risk patients
MonitorCapillary glucose q1–2 h in liver failure
📖 AASLD / national paracetamol protocolReviewed July 2026

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