N-acetylcysteine : Liver Injury

• N-acetylcysteine is commonly used for the treatment of acetaminophen toxicity, but it may be beneficial in other forms of acute liver failure.¹
• N-acetylcysteine is reasonable to give to patients who are not candidates for liver transplantation, to patients in whom acetaminophen toxicity may be contributing to the liver failure (eg, a patient with acute hepatitis B who was taking acetaminophen for right upper quadrant pain), and to patients with an indeterminate cause for the acute liver failure. ¹

Evidences: Acute Liver Failure

• A placebo-controlled trial involving 173 patients with acute liver failure due to causes other than acetaminophen (mainly drug-induced liver injury, autoimmune hepatitis, hepatitis B virus, or indeterminate) found significantly higher transplant-free survival (40 versus 27 percent) in patients randomized to N-acetylcysteine (initial loading dose 150 mg/kg per hour over one hour followed by 12.5 mg/kg per hour for four hours, then continuous infusions of 6.25 mg/kg per hour for the remaining 67 hours). 
• The benefit appeared to be confined to patients with early stage hepatic encephalopathy. ¹
• 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.⁴
  There is one study on the role of N-acetylcysteine in adults with non-acetaminophen-induced acute liver failure (NAI-ALF) in a center without facility of liver transplantation shows that the usage of NAC is associated with a reduction in NAI-ALF moratlity and was safe to use.⁵
• Evidences: non-alcoholic fatty liver disease. 
• Better results may be achievable in a longer follow up in this kind of patient. ²

Evidences: Dengue fever

• The usage of N-acetylcysteine as an artificial liver support are currently used as a bridge to liver transplantation but there are some limitations including lack of randomization, small sample size, and the nature of multiple organ failure in severe forms of dengue infection. 
• Thus, the usage of N-acetylcysteine should be considered for use on a case by-case basis.³

Conclusion

• Generally NAC can be used in the treatment of acetaminophen toxicity and it is also beneficial in patient who has liver injury due to other causes but the usage of the NAC in this kind of patient must be monitored and and should be considered to use on a case by-case basis.

References: 1. uptodate.com
2. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3270338/
3. http://www.tm.mahidol.ac.th/seameo/2015-46-1-suppl/c4-03p99-107.pdf
4. http://www.gastrojournal.org/article/S0016-5085(09)00915-9/abstract
5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790590/