NACSTOP - Safety of a 12-hour NAC Protocol

Written by Clay Smith

Spoon Feed
A 250mg/kg, 12-hour N-acetylcysteine (NAC) protocol was as effective as the usual 300mg/kg, 20-hour protocol in patients at lower risk for hepatotoxicity.

Why does this matter?
What if it was safe to medically clear a potential APAP overdose in 12 hours instead of 24? That would be good, but is it safe?

Stop the NAC
This was a cluster RCT with about 50 patients per group. To be enrolled in the study, they had to have a 4-hour level of at least 150mg/L but be considered low risk for hepatotoxicity, with “normal serum alanine transaminase (ALT) and creatinine on presentation and at 12 hours, and less than 20 mg/L acetaminophen at 12 hours.” Exclusions included: “pregnancy, acetaminophen modified-release ingestion, and other supratherapeutic ingestions (i.e., unintentional ingestions of more than 10 g or more than 200 mg/kg over 24 hours, more than 6 g/day over 48 hours).”

Patients received a fairly standard 20-hour 300mg/kg NAC protocol (consisting of 200 mg/kg over 4 hours followed by a further 100 mg/kg over 16 hours) or an abbreviated 12-hour 250mg/kg NAC protocol. The truncated protocol held the last 8 hours (50mg/kg) of the infusion if the serum ALT was <40, creatinine was normal, and acetaminophen was < 20 mg/L. There was no difference in the primary outcome of hepatic injury at 20 hours, defined as a doubling of the ALT and peak >100. There was also no difference in secondary outcomes, including ALT > 1,000, peak INR, or adverse drug reaction. Zero patients had hepatic injury in each group; none had delayed hepatic injury; none died; all were well at phone follow up on day 14.

Another Spoonful
I saw this article first in the excellent publication - Journal Watch.

The NACSTOP Trial: A Multicenter, Cluster-Controlled Trial of Early Cessation of Acetylcysteine in Acetaminophen Overdose. Hepatology. 2019 Feb;69(2):774-784. doi: 10.1002/hep.30224. Epub 2019 Jan 19.

Open in Read by QxMD

Reviewed by Thomas Davis

Member Login
Welcome, (First Name)!

Forgot? Show
Log In
Enter Member Area
My Profile Sign up to get full access. Log Out