Pharmacological Aspects and Clues for the Rational Use of Chloroquine / ydroxychloroquine Facing the Therapeutic Challenges of COVID-19 Pandemic

Abstract

Since there is an urgent need for COVID-19 treatment, the pandemic disease caused by SARS-CoV-2, the repurposing of available drugs is a quick and cheap option, with chloroquine (CQ) and hydroxychloroquine (HCQ) being the most quoted drugs in this context. As a rigorous evaluation of the available data is needed to help to decide on the eventual use of these drugs, the first objective of this work is to critically review the available in vitro assay, clinical studies and putative mechanism(s) of action of CQ/HCQ concerning COVID-19, either alone or in association with azithromycin (AZM). The second objective is to discuss the drug alternatives to treat COVID-19, with emphasis on Brazil, Latin America, and countries where malaria is endemic. Finally, we describe some of the on-going international clinical trials and their therapeutic schemes. We conclude that: 1) there is a good rationale for HCQ use, at least within a compassionate approach, for COVID-19 treatment, possibly at not to severe stage of the disease; 2) the risk/benefit ratio of HCQ use alone or in combination with other drugs such as AZM has yet to be established with the available level of evidence, according to the evidence-based medicine principles.