She added: “Is it triggered by pure hatred of Trump? Of Fox? Of me?” (Ms. Ingraham prefaced her remarks by reminding viewers: “I’m not a doctor; I don’t play one on TV.”)

Since mid-March, hydroxychloroquine has been a staple of the right-wing news media venues that Mr. Trump follows closely, including Rush Limbaugh’s radio show and Fox News prime time.

Ms. Ingraham was an early and enthusiastic advocate. On April 2, she told her viewers that “nearly all the experts that I’ve talked to, and the studies I’ve read, review this information, the evidence, and at this point, it’s come across as pretty much of a game changer.” The next day, she met with Mr. Trump in the Oval Office to personally pitch him on the drug.

Doctors around the country have prescribed hydroxychloroquine to patients for weeks despite the lack of rigorous trials. Some physicians say, given the speed and severity of the coronavirus, they are turning to any medicinal tools they can to save lives, even as little evidence has emerged that hydroxychloroquine is a panacea. Gov. Andrew M. Cuomo of New York has allowed that, “anecdotally,” doctors have seen positive results from the treatment, while reminding people that reliable data may take months to collect.

On Fox News, though, Ms. Ingraham acknowledged those caveats in passing, leaving an impression that a skeptical bureaucracy was keeping Americans from benefiting from a miracle drug.

On April 9, she began her program by mocking the director of the Centers for Disease Control and Prevention, Dr. Robert Redfield, for “essentially dismissing, trashing” hydroxychloroquine “despite all of its success stories.” She told viewers that the doctors booked on her program that night — “my medicine cabinet” — would “set the record straight.” (Fox News said on Wednesday that Ms. Ingraham’s segments about hydroxychloroquine always included a doctor or recovered coronavirus patient.)

Later on the show, she interviewed a patient, Billy Saracino, who, by his account, recovered from the coronavirus because his wife was inspired by “The Ingraham Angle” to help arrange a prescription for hydroxychloroquine.