Hamadan University of Medical Sciences Avicenna Journal of Pharmaceutical Research 2717-1884 4 2 2023 12 29 The Effect of Methylene Blue on COVID-19 Patients’ Treatment: A Double-Blind Placebo-Controlled Clinical Trial 87 91 10.34172/ajpr.1103 EN Javad Saffari-Chaleshtori https://orcid.org/0000-0001-9739-5907 Masoud Hafizi https://orcid.org/0000-0001-8003-9041 Ali Baradaran https://orcid.org/0000-0003-4992-1989 Keyhan Ghatreh-Samani https://orcid.org/0000-0001-8993-0527 Roohollah Mohseni https://orcid.org/0000-0001-9759-0876 Akbar Soleimani https://orcid.org/0000-0002-0763-6285 Journal Article 10.34172/ajpr.1103 2024 10 12 2025 01 20 Background: COVID-19 became widespread in 2019 worldwide and affected everyone. Even though it was a disease caused by a new strain of coronavirus with severe symptoms, some drugs could be effective in its treatment. It seems that methylene blue (MB), a drug for treating methemoglobinemia, can be a useful COVID-19 treatment. Methods: Overall, 60 COVID-19 patients with an O2 saturation of less than 85% and with no underlying diseases were chosen and included in this study. The patients were divided into the placebo control group (n=30) and the MB-treated group (n=30) and received 1 mg/kg of MB for 4 days. Some serum parameters were measured before and after 4 days of treatment. In addition, the O2 saturation was measured every 12 hours. Then, the results were compared with each other. Results: MB decreased the serum C-reactive protein (P=0.14), lactate dehydrogenase (P=0.08), and creatinine (P=0.12) in the COVID-19 patients non-significantly and increased the serum aspartate aminotransferase (P=0.40) and alanine aminotransferase (P=0.36) parameters in comparison with the control placebo group. However, it had no significant effect on O2 saturation (P=0.52) in COVID-19 patients. Conclusion: MB, a specific drug for treating methemoglobinemia, had no significant effect on COVID-19 patients.