Clinical efficacy of N-acetylcysteine for COVID-19: A systematic review and meta-analysis of randomized controlled trials

Background: The association between N-acetylcysteine (NAC) and COVID-19 remains undetermined; therefore, this meta -analysis assessed the clinical efficacy of NAC in the treatment of patients with COVID-19. Methods: This study searched PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov for studies published from their inception to December 17, 2022. Only randomized controlled trials (RCTs) that assessed the clinical efficacy of NAC for patients with COVID-19 were included. Results: Five RCTs involving 651 patients were included. There was no significant difference in mortality between the study group receiving NAC and the control group (15.6 % [50/320] vs. 32.3 %, [107/331]; risk ratio [RR]: 0.58; 95 % confidence interval [CI]: 0.24-1.40). In addition, the two groups did not differ with respect to the incidence of invasive mechanical ventilation (RR: 0.93; 95 % CI: 0.65-1.33), the risk of intensive care unit (ICU) admission (RR: 0.86; 95 % CI: 0.62-1.21), the length of hospital stay (mean difference [MD]: 0.17 days; 95 % CI: - 0.67-1.01), and the length of ICU stay (MD: -0.77 days; 95 % CI: - 2.97-1.42). Conclusions: The administration of NAC did not improve the clinical outcomes of patients with COVID-19; its routine use is not recommended for patients with SARS-CoV-2 infections.