NAC Dosing for APAP Overdose

Calculates NAC dosing for acetaminophen overdose based on Rumack-Matthew nomogram and provides standard 21-hour IV and oral protocols.

Patient Weight *

Many institutions cap at 100 kg for NAC dosing

Acetaminophen Serum Level

mcg/mL

Required for Rumack-Matthew nomogram interpretation

Hours Post-Ingestion

hours

Time from ingestion to blood draw. Nomogram valid 4-24 hours.

NAC Route *

IV is preferred for most patients; oral may be used if IV unavailable

IV Protocol

FDA 3-bag is standard; 2-bag is increasingly used for simplicity

Massive Overdose (>300 mcg/mL at 4h or staggered ingestion)

Yes

May require extended or higher-dose NAC therapy

Enter values and click Calculate to see results.

Acetaminophen Toxicity Workup - Medscape — Medscape (2024). https://emedicine.medscape.com/article/820200-workup
Practice Patterns for N-acetylcysteine Dosing for Acetaminophen Overdose — PMC/MDPI (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12090092/
Update: Can a simplified 2-bag acetylcysteine approach improve tolerability — UIC Drug Information Group (2025). https://dig.pharmacy.uic.edu/faqs/2025-2/august-2025-faqs/update-can-a-simplified-2-bag-acetylcysteine-approach-improve-tolerability-in-acetaminophen-overdoses/
Acetylcysteine Treatment of Acetaminophen Overdose — MDPI (2025). https://www.mdpi.com/2673-4389/5/2/20