N‑acetylcysteine and coronavirus disease 2019: May it work as a beneficial preventive and adjuvant therapy? A comprehensive review study

Background: Coronaviruses are major pathogens of respiratory system causing different disorders, including the common cold, Middle East respiratory syndrome, and severe acute respiratory syndrome. Today’s global pandemic coronavirus disease 2019 (COVID‑19) has high mortality rate, with an approximate of 20% in some studies, and is 30–60 times more fatal than the common annual influenza, However, there is still no gold standard treatment for it. N‑acetylcysteine (NAC) is a well‑known multi‑potential drug with hypothetically probable acceptable effect on COVID‑related consequences, which we completely focused in this comprehensive review. Materials and Methods: PubMed, Scopus, Science Direct, and Google Scholar have been searched. Study eligibility criteria: efficacy of NAC in various subclasses of pathogenic events which may occur during COVID‑19 infection. Efficacy of NAC for managing inflammatory or any symptoms similar to symptoms of COVID‑19 was reviewed and symptom improvements were assessed. Results: Randomized clinical trials introduced NAC as an antioxidant glutathione analog and detoxifying agent promoted for different medical conditions and pulmonary disorders to alleviate influenza and reduce mortality by 50% in influenza‑infected animals. The beneficial effects of NAC on viral disorders, including Epstein–Barr virus, HIV and hepatitis, and well‑known vital organ damages were also exist and reported. Conclusion: We classified the probable effects of NAC as oxidative‑regulatory and apoptotic‑regulatory roles, antiviral activities, anti‑inflammatory roles, preventive and therapeutic roles in lung disorders and better oxygenation functions, supportive roles in intensive care unit admitted patients and in sepsis, positive role in other comorbidities and nonpulmonary end‑organ damages or failures and even in primary COVID‑associated cutaneous manifestations. Based on different beneficial effects of NAC, it could be administered as a potential adjuvant therapy for COVID‑19 considering patient status, contraindications, and possible drug‑related adverse events.