Background: SARS-CoV-2 infection produces pneumonia with pulmonary alveolar collapse and in some cases sepsis and septic shock. There is no specific treatment for COVID-19. Vitamin C (Vit C), Vitamin E (Vit E), N-acetylcysteine (NAC) and Melatonin (MT) increase the intracellular content of GSH, kidnap free radicals and protect DNA, proteins in the cytosol and lipids of cell membranes. Pentoxifylline (Px) has anti-inflammatory activities. Methods: Here we evaluate the effect of Vit C, Vit E, NAC, and MT plus Px in COVID-19 patients with moderate and severe pneumonia. 110 patients of either sex were included. They were divided into five groups with 22 patients each. Group 1 received Vit C+Px, group 2 Vit E+Px, group 3 NAC+Px, group 4 MT+Px, and group 5 only Px. Oxidative stress markers as Lipid peroxidation levels, evaluation of total antioxidant capacity and nitrites were evaluate by spectrophotometry, and by ELISA assay IL-6 levels. Results: The antioxidant therapy improved the survival scores including SOFA, Apache II, SAPS II, COVIDGRAM and GCS. OS markers in plasma such as LPO (p≤0.04) and TAC (p≤0.03) decreased in COVID-19 patients administered with antioxidants. There was an increase of IL-6 (p≤0.01) and decreases of CRP (p≤0.01) and PCT (p≤0.05) in COVID-19 patients when entering the hospital and the different antioxidants reversed this alteration at the end of the hospital stay. Conclusions: This study confirms the presence of OS in COVID-19 patients. The results suggest that the treatment with antioxidant supplements such as Vit C, E, NAC, and MT plus Px could contribute to the deceleration of the aggressive and lethal development COVID-19. There is evidence that antioxidants in moderate doses decrease inflammation and control of OS; therefore, their use as an adjuvant therapy to improve prognosis is confirmed. The antioxidant therapy can be effective in this pandemia since it improves all of the survival scores including SOFA, Apache II, SAPS II, COVIDGRAM, GCS by lowering the LPO, IL-6, CRP, PCT and increasing systemic TAC.
