Efficacy and safety of acetylcysteine in "non-acetaminophen'' acute liver failure: A meta-analysis of prospective clinical trials

Background: Acute liver failure (ALF) is a rare but highly mortal condition without liver transplantation (LT). N-acetylcysteine (NAC), a glutathione precursor that detoxifies the reactive metabolite of acetaminophen and replenishes hepatic glutathione stores, is a highly effective drug for the prevention of ALF caused by acetaminophen. However, therapeutic use of NAC in non-acetaminophen-induced ALF (NAI-ALF) including alcohol intoxication, hepatitis virus infection, or drug and toxin-related hepatotoxicity is still inconclusive. The aim of this article is using meta-analysis method to analyze recent prospective clinical trials for the safety and efficacy of NAC in patients with ALF not caused by acetaminophen poisoning. Methods: Prospective clinical trials comparing efficacy and safety between NAC and control in the treatment of NAI-ALF were identified by searching Pubmed (2000-2014) and EMBASE (2000-2014) using the search terms acetylcysteine or NAC and NAI-ALF. The primary outcome was overall survival. Secondary outcomes included liver transplantation-free survival, post transplantation survival, length of ICU and hospital stays, and the relationship with coma grade. The safety profiles were also analyzed. Results: Four clinical trials were selected for meta-analysis. A total of 331 patients receiving treatment with NAC (oral or intravenously) and 285 patients in control group were included for meta-analysis. No statistical difference was identified between NAC group and control group for overall survival [236/331 (71%) vs 191/285 (67%); 95% CI 1.16 (0.81-1.67); P = 0.42]. However, there were significant differences between NAC group and control group regarding the survival with native liver [112/273 (41%) vs 68/226 (30%); 95% CI 1.61 (1.11-2.34); P = 0.01] and posttransplantation survival [78/91 (85.7%) vs 50/70 (71.4%); 95% CI 2.44 (1.11-5.37); P = 0.03]. The identified side effects of NAC included nausea, vomiting, and diarrhea or constipation. Rarely, it could cause rashes, fever, headache, drowsiness, low blood pressure, and elevated serum transaminase levels in a patient with cystic fibrosis. At the dose used for acetaminophen toxicity, acetylcysteine does not have hepatotoxic effects. Conclusion: NAC is safe for NAI-ALF. It can prolong patients' survival with native liver without transplantation and survival after transplantation, but it cannot improve the overall survival. (C) 2015 Published by Elsevier Masson SAS.