Effectiveness of hydroxychloroquine to treat COVID-19 – a comprehensive review

Effectiveness of hydroxychloroquine to treat COVID-19 – a comprehensive review

Last Reviewed : 12/16/2020
Effectiveness of hydroxychloroquine to treat COVID-19 – a comprehensive review

As COVID-19 pandemic is sweeping across the globe, taking thousands of lives, there has been extensive research for a potent medication that can cure the illness. Lately, hydroxychloroquine is being touted as the curative medicine for COVID-19. On March 28, 2020, U.S Food and Drug Administration (FDA) even authorized emergency approval to use hydroxychloroquine for patients admitted to hospital with COVID-19. In this article, we review all the existing evidence and conclude if hydroxychloroquine is as effective as it is being touted.

An article published in The British Medical Journal on April 8, 2020, mentioned that there are at least 80 trials of chloroquine, hydroxychloroquine or combination with other drugs, registered worldwide. This article reviewed all the existing evidence and concluded that “use of these drugs is premature and potentially harmful”.

So far, there are only two published studies that included clinical trials. Some review articles have also been published. There are several unpublished studies and abstracts that are not authoritative and they are not reviewed here. Multiple other studies were conducted on cell cultures and not on human beings. Several large authentic studies have yet to publish their findings.

The first clinical trial published in Zhejiang University Journals included 30 patients. 15 patients received hydroxychloroquine and 15 patients received supportive care. On day 7, 88% of patients who receieved hydroxychloroquine had a negative COVID-19 test. 93% of patients who did not receive hydroxychloroquine had a negative test. There is no much difference between the two groups. The study concluded that a larger study may be needed to investigate the effects of hydroxychloroquine in the treatment of COVID-19.

The second study that recently gained prominence included hydroxycloroquine and azithromycin combination to treat COVID-19. Twenty-six patients participated in the study but six patients dropped out. After 6 days of treatment, there was a significant reduction in the viral load. Even though this study attracted international audience including the president of the United States, the sample size of 20 patients is too small to deduce any significant findings. The study also focused on the viral load and not on the clinical features of the patients.

A retrospective review published in the journal Bioscience Trends, looked at 15 Chinese studies that included more than 100 patients with COVID-19 associated pneumonia. The review concluded that chloroquine is superior to the control treatment to shorten the disease course and inhibit exacerbation of pneumonia.

Singh AK et al. published a review recommending a fast track clinical trial including chloroquine and hydroxychloroquine drugs. They concluded that these drugs may be carefully considered for clinical use as experimental drugs. Similarly, another review by Cortegiani et al. recommended clinical use of chloroquine as part of emergency protocol and further trials are urgently needed.

A comprehensive review published in British Journal of General Practice on April 7, 2020, concluded that “there is insufficient evidence to recommend these drugs by primary care physicians for COVID-19 outside of the context of research”. It reported that “the data from clinical trials is limited, with mixed findings, which are likely to be prone to bias due to methodological limitations”.

In summary, it is still too early to jump to the conclusion that hydroxychloroquine is the holy grail for the treatment of COVID-19. While it shows some promising results, large clinical trials are needed to validate these findings. We may have to wait for the final results of large studies like ORCHID study, conducted by National Institutes of Health (NIH), to figure out if hydroxychloroquine can be a sustainable treatment option for COVID-19.



  • Covid-19: US gives emergency approval to hydroxychloroquine despite lack of evidence. BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1335 (Published 01 April 2020)
  • Chrloroquine and hydroxychloroquine in covid-19. BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1432 (Published 08 April 2020)
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