WASHINGTON — Rudy Giuliani, who was in the center of the impeachment storm earlier this year as an unpaid private attorney for President Trump, has cast himself in a new role: as personal science adviser to a president eager to find ways to short circuit the coronavirus epidemic.

Rudy Giuliani

In one-on-one phone calls with Trump, Giuliani said, he has been touting the use of an anti-malarial drug cocktail that has shown some early promise in treating COVID-19, but whose effectiveness has not yet been proved. He said he now spends his days on the phone with doctors, coronavirus patients and hospital executives promoting the treatment, which Trump has also publicly lauded.

“I discussed it with the president after he talked about it,” Giuliani said in an interview. “I told him what I had on the drugs.”

Giuliani’s advice to Trump echoes comments the former New York mayor has made on his popular Twitter feed and a podcast that he records in a makeshift radio studio installed at his New York City apartment, where he has repeatedly pushed the drug combination, as well as a stem cell therapy that involves the extraction of what Giuliani termed “placenta ‘killer cells.’ ”

The former New York mayor is part of a chorus of prominent pro-Trump voices who at first downplayed the severity of the virus and then embraced possible cures – worrying health experts who fear such comments undermine efforts to slow the virus’s spread and downplay the risks of the unproven treatments.

Giuliani’s controversial comments have helped him regain a bit of the prominence he had during impeachment – last week, he was back in the spotlight when Twitter briefly locked his account for promoting misinformation about COVID-19, the disease caused by the novel coronavirus.

“​He’s been out of the news and out of the limelight since the end of the impeachment drama,” said Andrew Kirtzman, a Giuliani biographer who is writing his second book about the former New York mayor. “What you’re seeing is an effort to regain relevance.”

The White House did not respond to a request for comment about the president’s conversations with Giuliani.

Giuliani’s name has not come up during meetings of the administration’s coronavirus task force, according to two members of the group, who spoke on the condition of anonymity to describe internal dynamics.

However, Giuliani said he has spoken directly to Trump “three or four times” about the potential coronavirus treatment, describing to him the results of an initial small-scale study in France that suggested the anti-malarial drug hydroxychloroquine may help treat COVID-19. Giuliani said he has not spoken to other White House officials about his views.

“There are obviously other people around him who agree with me,” Giuliani said.

The drug cocktail has been touted on Fox News and One America News Network, a cable news favorite of the president, and New York Gov. Andrew Cuomo, a Democrat, has said there is a “good basis” to believe the treatment could work and directed that it be distributed to New York hospitals.

At his daily briefings, Trump has praised the drug combo, saying it could be one of “the biggest game changers in the history of medicine.”

Last week, the FDA issued emergency authorization for the use of the anti-malarial drug for some COVID-19 patients.

FDA spokesman Michael Felberbaum said decision was made by expert career staffers, after extensive discussions with officials at other government agencies and based on the scientific evidence available.

“The known and potential benefits to treat this serious or life-threatening virus outweigh the known and potential risks when used under the conditions described in (the order),” he said.

On Saturday, Trump said the drug had passed the “safety test” and that he had seen results that were positive.