N-acetylcysteine (NAC), an antidote for acetaminophen poisoning, might benefit patients with non-acetaminophen related acute liver failure.
In a prospective, double-blind trial, acute liver failure patients without clinical or historical evidence of acetaminophen overdose were stratified by site and coma grade and randomly assigned to groups that were given NAC or placebo (dextrose) infusion for 72 hours. The primary outcome was overall survival at 3 weeks. Secondary outcomes included transplant-free survival and rate of transplantation.
A total of 173 patients received NAC (n=81) or placebo (n=92). Overall survival at 3 weeks was 70% for patients given NAC and 66% for patients given placebo (one-sided p=0.283). Transplant-free survival was significantly better for NAC patients (40%) than for those given placebo (27%; one-sided p=0.043). The benefits of transplant-free survival appeared to be confined to the 114 patients with coma grade I–II who received NAC (52% compared with 30% for placebo; one-sided p=0.010); transplant-free survival for the 59 patients with coma grade III–IV was 9% in those given NAC and 22% in those given placebo (one-sided p=0.912). The transplantation rate was lower in the NAC group but not significantly different between groups (32% vs. 45%; p=0.093). Intravenous NAC was generally well tolerated; only nausea and vomiting occurred significantly more frequently in the NAC group (14% vs. 4%; p=0.031).
Intravenous NAC improves transplant-free survival in patients with early stage non-acetaminophen related acute liver failure. Patients with advanced coma grades do not benefit from NAC and typically require emergency liver transplantation. (ClinicalTrials.gov number NCT00004467)