© George Frey | AFP | Getty ImagesHydroxychloroquine
The Food and Drug Administration said Monday it is ending its emergency use authorization for chloroquine and hydroxychloroquine, the anti-malaria drugs backed by President Donald Trump to combat Covid-19.

The agency determined the drugs were "unlikely to be effective in treating COVID-19 for the authorized uses in the EUA."

"Additionally, in light of ongoing serious cardiac adverse events and other serious side effects, the known and potential benefits of CQ and HCQ no longer outweigh the known and potential risks for the authorized use," the FDA wrote in its notice Monday.

The FDA issued the emergency use authorization for the drugs in March. The EUA meant that doctors would be allowed to use the drugs on patients hospitalized with Covid-19 even though they had not been formally approved by the agency.

However, the agency warned consumers a month later against taking the drugs to treat Covid-19 outside a hospital or formal clinical trial setting due to the risk of "serious heart rhythm problems" in some patients.

Trump disclosed last month that he was taking hydroxychloroquine daily to prevent infection from the coronavirus.White House physician Dr. Sean Conley released a memo that said that after discussing evidence for and against hydroxychloroquine with Trump, they concluded "the potential benefit from treatment outweighed the relative risks."

In addition to treating malaria, hydroxychloroquine is often used by doctors to treat rheumatoid arthritis and lupus. It is known to have serious side effects, including muscle weakness and heart arrhythmia. Numerous clinical trials are looking to see if it's effective in fighting Covid-19, but it is not a proven treatment.

A recent study published in the New England Journal of Medicine found hydroxychloroquine was no better than a placebo in preventing infection of the coronavirus.

The study, the first randomized, placebo-controlled trial, which is considered the "gold standard" in science, looked at 821 people in the United States and Canada who had been exposed to the coronavirus.

There are no FDA-approved drugs for the treatment of Covid-19, which has infected more than 7.9 million people worldwide and killed at least 434,060, according to data compiled by Johns Hopkins University. On May 1, the FDA granted emergency use authorization for Gilead Sciences' remdesivir drug to treat Covid-19.

Even though hydroxychloroquine is not a proven treatment for the coronavirus, some people across the world have been taking it after a handful of small studies published earlier in the year suggested it could be beneficial and Trump promoted the drug as a potential treatment for the virus.

A recent JAMA study found U.S. prescriptions for the drug surged nearly 2,000% in March when the president initially touted the drug as a possible treatment.