The effect of N-acetylcysteine on exacerbations of chronic obstructive pulmonary disease: A meta-analysis and systematic review

Heart Lung. 2017 Mar-Apr;46(2):120-128. doi: 10.1016/j.hrtlng.2016.12.004. Epub 2017 Jan 18.


N-acetylcysteine (NAC) is an antioxidant and anti-inflammatory. Its effects on chronic obstructive pulmonary (COPD) outcomes, including exacerbation of and changes in lung function parameters, are controversial. To investigate the effects of NAC on COPD exacerbation and changes in lung function parameters in patients with COPD. A meta-analysis of randomized controlled trials retrieved from PubMed and Medline databases (12 trials; 2691 patients). High-dose [relative ratio (RR) = 0.90, 95% confidence interval (CI) = 0.82-0.996, P = 0.041] and low-dose (RR = 0.83, 95% CI = 0.69-0.99, P = 0.043) NAC reduced COPD exacerbation prevalence. Long-term (≥6 months), but not short-term, NAC reduced exacerbation prevalence (RR = 0.85, 95% CI = 0.74-0.98, P = 0.024). NAC did not affect exacerbation rate, forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), or inspiratory capacity (IC). Long-term NAC therapy may reduce risk of COPD exacerbation.

Keywords: Chronic obstructive pulmonary disease; Effect; Exacerbation; Meta-analysis; N-acetylcysteine.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Acetylcysteine / therapeutic use*
  • Anti-Inflammatory Agents / therapeutic use
  • Forced Expiratory Volume / drug effects
  • Free Radical Scavengers / therapeutic use
  • Humans
  • Inspiratory Capacity / drug effects
  • Pulmonary Disease, Chronic Obstructive / drug therapy*
  • Pulmonary Disease, Chronic Obstructive / physiopathology


  • Anti-Inflammatory Agents
  • Free Radical Scavengers
  • Acetylcysteine