COVID-19 pandemic has spread worldwide at an exponential rate affecting millions of people instantaneously . Currently, various drugs are under investigation to treat an enormously increasing number of COVID-19 patients . This dreadful situation clearly demands an efficient strategy to quickly identify drugs for the successful treatment of COVID-19 . Hence, drug repurposing is an effective approach for the rapid discovery of frontline arsenals to fight against COVID-19 . Successful application of this approach has resulted in the repurposing of some clinically approved drugs as potential anti-SARS-CoV-2 candidates . Several of these drugs are either antimalarials, antivirals, antibiotics or corticosteroids and they have been repurposed based on their potential to negate virus or reduce lung inflammation . Large numbers of clinical trials have been registered to evaluate the effectiveness and clinical safety of these drugs . Till date, a few clinical studies are complete and the results are primary . WHO also conducted an international, multi-country, open-label, randomized trials-a solidarity trial for four antiviral drugs . However, solidarity trials have few limitations like no placebos were used, additionally any drug may show effectiveness for a particular population in a region which may get neglected in solidarity trial analysis . The ongoing randomized clinical trials can provide reliable long-term follow-up results that will establish both clinical safety and clinical efficacy of these drugs with respect to different regions, populations and may aid up to worldwide COVID-19 treatment research . This review presents a comprehensive update on majorly repurposed drugs namely chloroquine, hydroxychloroquine, remdesivir, lopinavir-ritonavir, favipiravir, ribavirin, azithromycin, umifenovir, oseltamivir as well as convalescent plasma therapy used against SARS-CoV-2 . The review also summarizes the data recorded on the mechanism of anti-SARS-CoV-2 activity of these repurposed drugs along with the preclinical and clinical findings, therapeutic regimens, pharmacokinetics, and drug-drug interactions.
Index: COVID-19, SARS-CoV-2, antivirals, drug repurposing, mechanism of action, pharmacokinetics