Australian and New Zealand guideline authors, with representation from Poisons Information Centres, recommend a standard 20-hour, two-bag IV acetylcysteine regimen for most treated paracetamol-poisoning patients: 200 mg/kg over 4 hours followed by 100 mg/kg over 16 hours. RCH implementation guidance uses actual body weight with a 110 kg ceiling and the same 7 mL/kg then 14 mL/kg dilution-volume guide shown in this calculator.

Guideline role: the 2020 ANZ update states that the paracetamol nomogram applies to acute immediate-release ingestions with a known time, while modified-release overdose, massive overdose, accidental liquid ingestion in young children and repeated supratherapeutic ingestion require separate pathways.
Dose escalation: the same guideline recommends increased acetylcysteine dosing for massive ingestions with paracetamol concentrations more than double the nomogram treatment line. This is why the calculator includes a double-dose second-bag option.
Implementation data: the 2NAC multicentre observational study compared a 200 mg/kg over 4 hours plus 100 mg/kg over 16 hours regimen with the older three-bag regimen across paracetamol-overdose presentations from 2009 to 2019, reporting similar efficacy with fewer cutaneous and systemic non-allergic anaphylactic reactions (1.3% vs 7.1%).

This calculator only displays dose amounts and suggested dilution volumes. It does not decide whether acetylcysteine is indicated, handle repeated supratherapeutic ingestion or modified-release products, set stopping criteria, or replace local toxicology/Poison Information Centre advice for massive ingestion, pregnancy, established liver injury or complex presentations.

Australian/New Zealand dosing note

This calculator displays the ANZ two-bag IV acetylcysteine dose only after the decision to treat has been made. Nomogram eligibility, modified-release or repeated supratherapeutic ingestion pathways, pregnancy, paediatric fluids and massive-ingestion dose escalation should follow Poisons Information Centre and local hospital guidance.

ANZ Two-Bag IV Acetylcysteine Dosing for Paracetamol Poisoning