More caution is needed in using antimalarials against covid-19 – Claudia Grisanti


May 29, 2020 6:12 PM

On 24 May, the World Health Organization (WHO) suspended the testing of hydroxychloroquine against covid-19. The drug had been included in the Solidarity trial, which is studying the use of some drugs to treat covid-19, against which specific treatments do not yet exist. The drugs included were remdesivir, which was tested against the ebola virus, lopinavir / ritonavir, which is a treatment for HIV, interferon beta 1, which is used against multiple sclerosis, and hydroxychloroquine, used against malaria. and some autoimmune diseases. Hydroxychloroquine and chloroquine are two long-known drugs. The Solidarity project, which involves dozens of countries and hundreds of patients, aims to achieve significant results from the large-scale testing of the most promising drugs against the new coronavirus.

The off-label use of drugs is however possible even without a clinical trial, if you are in particular conditions. Already at the end of March, the WHO noted that against covid-19, doctors often prescribed authorized medicines for the treatment of other diseases.

Growing interest
One of the prescribed drugs was precisely hydroxychloroquine. Interest in this molecule was generated in part outside the scientific community, by a series of tweets in mid-March that promoted its use. U.S. President Donald Trump has also endorsed its use. His tweet cited a study published in the International Journal of Antimicrobial Agents. It was a small study, which involved twenty patients for ten days. A possible antiviral effect of hydroxychloroquine would emerge from this study.

In the week of March 15 to March 21, U.S. prescriptions for hydroxychloroquine and chloroquine increased significantly. For example, prescriptions below 28 pills grew 1,977 percent. The prescriptions for larger quantities have also increased.

Overall, over 480,000 more hydroxychloroquine and chloroquine prescriptions were registered in ten weeks, from 22 February to 25 April compared to the previous year. Long-term prescriptions subsequently declined, signaling the lack of the drug for patients with certain diseases, such as rheumatoid arthritis.

The Food and Drug Administration (FDA), in the United States, authorized the emergency use of chloroquine and hydroxychloroquine for patients hospitalized for covid-19 on March 28. In a comment published in Jama Internal Medicine magazine on May 19, Mike Zhai, Carolyn Lye and Aaron Kesselheim strongly criticized the decision. The FDA has given the green light on the basis of in vitro data and individual clinical cases, not of extensive trials. “Whether hydroxychloroquine and chloroquine have clinical efficacy against covid-19 or not, there is a great risk of damage deriving from the authorization issued on insufficient data,” they write in their comment. The FDA’s decision can push patients to use the two antimalarials outside of clinical trials, slowing down data acquisition.

Furthermore, while it is not yet known whether the two drugs are effective against covid-19, it is known that they can cause heart problems, even fatal ones. Finally, there is a risk of causing a shortage of the two drugs, which are necessary for other patients, not covid-19. “As the covid-19 pandemic continues, the public, members of the government and the pharmaceutical industry can put pressure on the FDA to issue additional authorizations for emergency use of drugs. Instead of succumbing to these pressures, the agency should ensure that authorizations are issued only when supported by sufficient scientific evidence, and all of this evidence should be made public at the time of authorization, “continue the researchers in their comment.


On May 22, the British medical journal The Lancet published a study on the use of hydroxychloroquine and chloroquine, with or without antibiotics, against covid-19, which revealed the risks associated with the two drugs. The study included data from over 96,000 patients in multiple countries. The patients were hospitalized. Among these, almost 15 thousand had received treatment with hydroxychloroquine, chloroquine or with the combination of one of the two preparations with an antibiotic. There was no benefit from treatment with the two drugs. Among the patients who received treatment there were multiple cases of heart arrhythmias and deaths. However, the study is observational and does not investigate the reasons for the increased risk of death.

Following the publication of the study, the World Health Organization suspended testing on hydroxychloroquine. A review of the safety of the treatment is therefore expected.

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