Drug Candidates for COVID-19 Treatment in Brazil: Updated Review and New Therapeutic Approaches

Background: The COVID-19 pandemic has evolved rapidly, causing significant global mortality and straining healthcare systems. While new therapeutic strategies are continually emerging, several repurposed drugs have been evaluated for their potential efficacy against SARS-CoV-2. Recent advancements in treatment protocols and the emergence of new variants necessitate an updated analysis of therapeutic options. Objective: This review critically analyzes the role of repurposed drugs, including chloroquine, ivermectin, and nitazoxanide, as well as corticosteroids, immunomodulators, and novel antiviral strategies for the treatment of COVID-19 in Brazil. The discussion incorporates emerging evidence from clinical trials and the latest research on treatment responses to new variants of the virus. Methodology: This study synthesizes evidence from clinical trials, systematic reviews, and meta-analyses available in databases such as PUBMED, BVS/BIREME, Web of Science, Science Direct, CAPES Portal, Cochrane Library, and PROSPERO. Studies evaluating the efficacy and safety of repurposed drugs and novel interventions in different phases of the disease were included. Results: While chloroquine, ivermectin, and nitazoxanide initially showed in vitro antiviral activity, randomized controlled trials have not demonstrated significant clinical benefits. However, dexamethasone and other corticosteroids remain the cornerstone for managing severe COVID-19 cases with respiratory failure. Additionally, monoclonal antibodies, antiviral drugs like remdesivir and molnupiravir, and immunomodulatory therapies, such as tocilizumab and baricitinib, have emerged as effective options, particularly against severe disease forms caused by new variants. Conclusion: Although initial enthusiasm for repurposed antiparasitic drugs has waned due to lack of robust evidence, corticosteroids, targeted antiviral therapies, and immunomodulators have demonstrated efficacy, especially in severe cases. Ongoing research is essential to refine treatment protocols and optimize therapeutic strategies for emerging SARS-CoV-2 variants.