Repurposing of chloroquine and hydroxychloroquine for the management of COVID-19

The Coronavirus Disease-19 (COVID-19) pandemic has impacted adversely on the global health and socio-economic activities. There is currently no evidence-based anti-SARS-CoV-2 drug for COVID-19 therapy. This review highlights some pharmacological properties of chloroquine and hydroxychloroquine and prospects of repurposing them for the treatment of COVID-19. Google scholar was employed in searching relevant published journal articles (n=118) in English. The search was later narrowed down to SARS-CoV-2, pathophysiology of COVID-19, available drugs for the management of COVID-19, clinical trials on repurposing drugs for COVID-19 therapy, and the role of chloroquine and hydroxychloroquine in the treatment of COVID-19. Documented evidence revealed that chloroquine and hydroxychloroquine have antiviral and immune-modulatory properties. Their antiviral effect is due to inhibition of the spike proteins of SARS-CoV-2 from binding to the cellular transmembrane receptors, angiotensin converting enzyme2 thereby preventing viral infections. Also, sequestration of these drugs into the lysosomes elevates lysosomal pH thus inhibiting lysosomal enzymatic functions vital for viral replication in those cells. Whereas, their immune-modulatory activity averts the inflammatory complications of COVID-19, particularly acute respiratory syndrome, by preventing cytokine storm through suppression of the production and putative release of pro-inflammatory cytokines. The adverse effects from these drugs, notably irreversible retinopathy and cardiac arrhythmia are rare but become life-threatening when they occur. These are minimal with hydroxychloroquine compared to chloroquine. Chloroquine and hydroxychloroquine could be repurposed for managing COVID-19 cases because they are already extensively used for treating acute nonresistant malaria and auto-immune diseases. Also, a viable vaccine cannot be available in the near future while there is a pressing need for treatments to lower the daily rise in morbidity and mortality associated with the disease. Nevertheless, we suggest that emphasis should be on hydroxychloroquine because of its superior antiviral effect and clinical safety.