Where are we with the use of N-acetylcysteine as a preventive and adjuvant treatment for COVID-19?

OBJECTIVE: As N-acetylcysteine (NAC) is promising as a re-purposed drug for the adjunctive or supportive treatment of serious COVID-19, this article aimed to describe current evidence. MATERIALS AND METHODS: A search was performed in PubMed/Medline for "NAC", "viral Infection", COVID-19", oxidative stress", "inflammation", retrieving preclinical and clinical studies. RESULTS: NAC is a pleiotropic molecule with a dual antioxidant mechanism; it may neutralize free radicals and acts as a donor of cysteine, restoring the physiological pool of GSH. Serious COVID-19 patients have increased levels of reactive oxygen species (ROS) and free radicals and often present with glutathione depletion, which prompts a cytokine storm. NAC, which acts as a precursor of GSH inside cells, has been currently used in many conditions to restore or protect against GSH depletion and has a wide safety margin. In addition, NAC has anti-inflammatory activity independently of its antioxidant activity. CONCLUSIONS: Clinical and experimental data suggest that NAC may act on the mechanisms leading to the prothrombotic state observed in severe COVID-19.