Revised IV acetylcysteine (NAC) protocol launching April 1, 2026
October 20, 2025
Dear Hospital Colleagues,
In 2024, the Ontario Poison Centre (OPC) supported health care providers in the care of more than 5,700 patients with acetaminophen poisoning. IV acetylcysteine (NAC) remains the cornerstone antidote for treating these cases.
On April 1, 2026, the OPC will launch a revised NAC protocol for acetaminophen poisoning. This update aligns with national standards across Canadian poison centres and reflects extensive consultation with pharmacists and clinical leaders across Ontario, Manitoba, and Nunavut.
To support a smooth and safe transition to the new protocol, we encourage you to share this information with medical, nursing, and pharmacy colleagues across all disciplines at your hospital. Several education and information sessions are available for health care providers, and additional resources can be found on our website.
Summary of the Revised Protocol:
Two-step, single concentration approach
- Use a 3% NAC solution (30mg/mL) in D5W, ½ NS, or NS
- Loading dose: 150 mg/kg over 1 hour
- Maintenance infusion: 15 mg/kg/hour, continued until stopping criteria are met (minimum duration of 12 hours)
Two methods of administration supported by OPC staff
- ““1 bag method”: Single admixture for both loading and maintenance steps
- Suitable if infusion pump can automatically switch between steps, with separate limits for
- On some pumps (e.g., Alaris, Plum 360), this can be programmed by building a continuous entry and using the bolus function for the loading
- “2 bag method”: Separate admixtures prepared for loading and maintenance steps
- Recommended if your infusion pump cannot automatically switch between steps (e.g., Baxter, B. Braun).
Additional activities to support implementation:
- Train-the-Trainer webinars: December 2025- January 2026 (registration link here, or on our website).
- Frontline “just-in-time” information sessions: February-March 2026
- Post-Implementation feedback sessions: April-June 2026
Thank you for your continued collaboration in improving care for poisoned patients across the province.
Sincerely,
Emily Austin, MD, FRCP(C)
Medical Director, Poison Centre
Additional Resources/Information: