As the Food and Drug Administration (FDA) on Monday revoked its emergency use authorization for Hydroxychloroquine to treat COVID-19 patients, President Donald Trump, who himself championed for the anti-malaria drug, said only US agencies have failed to grasp its benefit in fighting the coronavirus.

US regulators revoked the emergency authorisation for Hydroxychloroquine amid growing evidence they don’t work and could cause serious side effects.

The FDA said on Monday that the drugs hydroxychloroquine and chloroquine were unlikely to be effective in treating the novel Coronavirus. Citing reports of heart complications, the agency said the drugs’ unproven benefits “do not outweigh the known and potential risks”.

However, US Health Secretary Alex Azar clarified that the FDA ruling was limited to hospital use with “the most extreme cases” and the medicines have not been completely banned and doctors can continue to prescribe them.

Emergency use authorization allows medication to treat an ailment on an emergency basis without a full authorisation for the specific disease for which other medicines are not available.

House Speaker Nancy Pelosi also denounced its use claiming that HCQ “has not been approved by the scientists”, even though the Indian Council of Medical Research (ICMR) National Task Force on COVID-19 has recommended that healthcare workers and others caring for coronavirus patients use HCQ as a preventive.

The FDA’s assertion that data had not shown that HCQ and CQ were effective is at odds with another development that dealt a blow to the credibility of the prestigious medical journal, The Lancet over a study that claimed HCQ was not effective and appeared to increase the risk of death because of doubts about the data used.

The Lancet had to “deeply apologise” and withdraw the much-cited study when experts questioned the reliability of the data used in the study by three Indian origin scientists and another.

The World Health Organization that had stopped HCQ clinical trials on May 25 based on The Lancet study resumed them after it was withdrawn.

Earlier in May, President Donald Trump himself had taken a two-week dose of Hydroxychloroquine and said he was feeling “absolutely great”.

Trump has claimed to be taking the medicine many a times, while touting it as a “game changer”.

Trump personally phoned Prime Minister Narendra Modi to lift a ban of HCQ exports and allow those ordered by the US before the ban to be released.

Hydroxychloroquine, first approved in 1955, provided no benefit and potentially higher risk of death for patients at US veterans hospitals, according to an analysis that was submitted for an expert review in April.

Hydroxychloroquine sulfate was first synthesised in 1946 and is in a class of medications historically used to treat and prevent malaria. It is approved by the US Food and Drug Administration to treat malaria, rheumatoid arthritis, lupus, childhood arthritis, and other autoimmune diseases.