(CNN) A drug that's been touted by President Donald Trump as a "game changer" didn't help hospitalized patients with coronavirus and was associated with heart complications, according to a new study.

"This provides evidence that hydroxychloroquine does not apparently treat patients with Covid 19," said Dr. Paul Offit, an infectious disease specialist at Children's Hospital of Philadelphia. "Even worse, there were side effects caused by the drug -- heart toxicities that required it be discontinued."

Trump has said that hydroxychloroquine shows "tremendous promise" and has made it sound like the drug is harmless.

"I think it's going to be great," Trump said at a White House briefing on March 19.

"What do you have to lose? Take it," he said on April 4.

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