Early studies suggesting that chloroquine (CQ) and hydroxychloroquine
(HCQ) could benefit coronavirus patients brought these old medicines
back to the spotlight. This led to an increase in demand and price,
turning their counterfeiting a pharmacovigilance issue worldwide.
Meanwhile, lack of evidence on effectiveness and safety concerns have
reduced their clinical trials in severe COVID-19 cases. Despite the
knowledge that CQ and HCQ toxic effects are stereo specific rather than
their therapeutic effects, these drugs are available only as racemates.
In this context, this work brings a discussion about chiral switching to
their eutomers so that CQ and HCQ distomers would become impurities,
what may be a viable alternative to test new dose-response curves. Even
if it is proven that the use of pure CQ and HCQ enantiomers are useless
against COVID-19, chiral switching would certainly improve safety and
efficacy in the treatment of many autoimmune inflammatory diseases,
benefiting chronic users of these drugs.