Major clinical outcomes of melatonin use in COVID-19 patients: a systematic review

Introduction: In the context of the Sars-Cov-2 (COVID-19) pandemic, as well as other viral infections, these viruses can lead to significant morbidity and mortality. Thus, in the context of melatonin science in viral infections such as influenza and COVID-19, there is a growing realization that the regulation of melatonin pathways, both pineal and systemic, may be an important aspect of the regulation of viruses in cellular functions. Objective: It was to list the main results of clinical studies of the use of melatonin in patients infected with Sars-Cov-2 through a systematic review. Methods: The rules of the Systematic Review-PRISMA Platform. The search was carried out from December 2021 to April 2022 in Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: It was found 164 articles. A total of 86 articles were fully evaluated and 30 studies were developed in a systematic review. Melatonin is known as an anti-inflammatory agent and immune modulator that may address the progressive pathophysiology of coronavirus disease 2019 (COVID-19). According to the objective and results obtained in the present study that evaluated the treatment in patients with COVID-19, the use of melatonin can help reduce thrombosis, sepsis and mortality. Furthermore, the combination of 3.0 mg oral melatonin tablets and standard care can substantially improve sleep quality and blood oxygen saturation in hospitalized patients. Clinical symptoms such as cough, dyspnea and fatigue, as well as the polymerase chain reaction (PCR) level and lung involvement in patients receiving melatonin can improve significantly. Also, the mean time of patients' hospital discharge and return to initial health was significantly shorter in patients who received melatonin compared to the control group. There was evidence of benefit of sustained-release melatonin 2 mg in therapy in patients, as well as evidence that the use of melatonin was associated with a reduced probability of a positive SARS-CoV-2 test result compared to the use of blockers of the angiotensin II receptor or angiotensin-converting enzyme inhibitors.