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Chloroquine and hydroxychloroquine in covid-19

BMJ 2020; 369 doi: (Published 08 April 2020) Cite this as: BMJ 2020;369:m1432

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  1. Robin E Ferner, honorary professor of clinical pharmacology1,
  2. Jeffrey K Aronson, clinical pharmacologist2
  1. 1Institute of Clinical Sciences, University of Birmingham, Birmingham, UK
  2. 2Centre for Evidence-Based Medicine, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
  1. Correspondence to: R E Ferner r.e.ferner{at}

Use of these drugs is premature and potentially harmful

TheBMJ in 1925 cautiously endorsed Moellgaard’s gold treatment for tuberculosis,1 although it found his pharmacological reasoning “both interesting and instructive.”2 We should be similarly cautious about proposed treatments for people infected with SARS-CoV-2, the virus that causes covid-19. Many proposals are based on in vitro investigations, studies in experimental animals, or experience with interventions in infections with other viruses, whether similar to SARS-CoV-2 (eg, SARS-CoV-1) or not (HIV).

This is all true of chloroquine and hydroxychloroquine, both 4-aminoquinolines, which have been suggested as potential treatments for covid-19. Currently, at least 80 trials of chloroquine, hydroxychloroquine, or both, sometimes in combination with other drugs, are registered worldwide.

The possible activity of 4-aminoquinolines in infectious mononucleosis was first proposed in 1960, before its viral cause was known.3 Several unsatisfactory clinical trials followed, some with positive results and some negative. In 1967 the authors of a small but well conducted randomised, double blind, placebo controlled trial of chloroquine concluded that “except for supportive measures, infectious mononucleosis is essentially untreatable.”4

Since then, many studies have shown that 4-aminoquinolines are active in vitro against a range of viruses. Their efficacy has …

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