Doctors should not use a drug combination strongly pushed by U.S. President Donald Trump to treat patients with coronavirus infections, a National Institutes of Health panel says in new guidelines published Tuesday. And any other experimental drugs should only be tried as part of a clinical trial, the panel said, according to CNN.

The guidelines, published online, are meant to guide doctors, nurses and other medical professionals treating patients with Covid-19 and will be updated in real time as more is learned in fighting the pandemic, the NIH said.

Trump has touted an antimalarial drug known as hydroxychloroquine, especially in combination with an antibiotic azithromycin, for treating Covid-19 even though there has been no medical recommendation to use it. Although a few very small studies have suggested it might help patients recover, more and more studies have shown that the drug combination may do little or no good and may increase the rate of other complications.

Asked about the NIH guidance on hydroxychloroquine and azithromycin during Tuesday, April 21's White House coronavirus task force meeting, President Trump said, "we'll take a look at that. I'm always willing to take a look."

The guidelines give details on which drugs should be used, but also when and how to provide extra oxygen to patients struggling to breathe, how to safely use equipment on potentially infectious patients and include what's known about heart, liver and kidney complications in patients.

The panel also urges caution in another treatment making headlines: the use of plasma from Covid-19 survivors. "There are insufficient clinical data to recommend either for or against the use of convalescent plasma or hyperimmune immunoglobulin for the treatment of COVID-19," it said.

More than 825,000 cases of Covid-19 have been registered in the United States so far, with over 45,000 deaths and more than 75,000 recoveries.