United States President Donald Trump on Monday stood by his support of hydroxychloroquine, saying that other countries provided “great reports” on the effectiveness of the anti-malarial drug for treating coronavirus, and only American agencies have failed to grasp its benefit, Reuters reported.

This came hours after the United States Food and Drug Administration revoked its emergency use authorisation for hydroxychloroquine and chloroquine. Trump has frequently touted the drugs for its effectiveness to stave off Covid-19, the disease caused by the coronavirus, and has even claimed to use it himself.

“All I know is that we’ve had some tremendous reports,” Trump said at a White House roundtable, according to The New York Times. “It certainly didn’t hurt me. I feel good.”

The authorisations were withdrawn after a request from Gary Disbrow, acting director of the Biomedical Advanced Research and Development Authority.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 anti-viral effect.

The drugs do not meet “the statutory criteria” for emergency use authorisation as they are unlikely to be effective in treating Covid-19, the Food and Drug Administration noted on its website. “Additionally, in light of ongoing serious cardiac adverse events and other serious side effects, the known and potential benefits of chloroquine and and hydroxychloroquine no longer outweigh the known and potential risks for the authorized use,” it added.

However, doctors can continue to legally prescribe the drugs off-label, as they can with any drug that’s approved for other conditions, PTI reported. The FDA’s action only ended the authorisation for hospitals to use the government’s stockpiles of the drugs on hospitalised patients, United States Secretary of Health and Human Services Alex M Azar said.

“In fact the FDA removal of the emergency use authorisation takes away what had been a significant misunderstanding by many that had made people think it could only be used in a hospital setting,” Azar added. “If a doctor wishes to prescribe it, working with a patient, they may prescribe it for any purpose that they wish to do so. And, this [the FDA’s decision] actually removes a potential barrier to them.”

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 World Health Organization on June 3 said that it will resume clinical trials of anti-malarial drug hydroxychloroquine.