Oral high-dose acetylcysteine: Effective against the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)?

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a high rate of transmission and it exhibits immune escape characteristics. N-acetyl-L-cysteine (NAC) is a precursor of reduced glutathione (GSH), which can enter cells to play an antioxidant role, so it is better than glutathione. Patients tolerate NAC well, and adverse reactions are rare and mild, so this type of drug with multiple actions is considered to be a mucolytic agent as well as a drug for the prevention/treatment of various diseases, including COVID-19. Previous studies indicated that the clinical effectiveness of NAC is dose-dependent. Low-dose NAC (0.2 g tid for adults) is a mucolytic expectorant, high-dose NAC (0.6 g bid or tid) has expectorant action as well as antioxidant action, and extreme-dose NAC (300 mg/kg.d) is used for detoxification in cases of an acetaminophen overdose. Presumably, orally administered high-dose NAC (0.6 g tid for adults and 10 mg/kg tid for children) could be used as an adjuvant to treat an Omicron infection. It should reduce the time to negative conversion and prevent severe COVID-19, reducing the duration of hospitalization and increasing the bed turnover rate.