The United States’ Food and Drug Administration on Monday withdrew emergency use authorization for anti-malarial drug hydroxychloroquine in the treatment of the novel coronavirus, Politico reported. The authorisation for chloroquine was also withdrawn. President Donald Trump had heavily endorsed both drugs for the treatment of Covid-19 over the past couple of months.

The authorisations were withdrawn after a request from Gary Disbrow, acting director of the Biomedical Advanced Research and Development Authority. FDA Chief Scientist Denise Hinton said in a letter announcing the decision that the agency, after reviewing results from large clinical trials, believes the drugs are unlikely to produce any antiviral effect.

The FDA also said that the version of chloroquine that had been authorised for emergency use is not approved in the United States, and so all use of that drug will be stopped.

Use of hydroxychloroquine to prevent and treat Covid-19 has been a focus of public attention. India has been using the drug extensively and has also exported it to many foreign countries, including the United States. On May 22, the Ministry of Health and Family Welfare revised its advisory on the use of hydroxychloroquine as a prophylactic against the coronavirus. The ministry’s decision came after the National Task Force, constituted by the Indian Council of Medical Research, reviewed and recommended the use of the drug for coronavirus patients.

On May 25, the World Health Organization temporarily suspended trials of hydroxychloroquine, after a report in medical journal The Lancet claimed that it could increase patient mortality rate in hospitals. The study also found that those administered the drug showed a higher frequency of arrhythmia, or irregular heartbeat.

However, earlier this month, the journal retracted the study, after three of its authors said they could no longer vouch for its veracity as the healthcare firm that supplied the records would not allow an independent review of its dataset.

The United States is the worst-affected country in the world, with over 21 lakh cases, according to the Johns Hopkins University. More than 1,17,000 people have died.

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