It's the drug being hailed by scientists as a "major breakthrough" that will "save lives worldwide."
Results from a trial, led by a team from Oxford University, were announced in the U.K. on Tuesday, showing that the cheap and widely-used steroid dexamethasone reduced coronavirus death rates by around a third among the country's most severely ill COVID-19 patients.
It makes dexamethasone, which is used to reduce inflammation in other diseases such as arthritis, the first drug shown to be able to save lives among COVID-19 patients, and the researchers who led the trials said preliminary results suggest the drug should immediately become standard care in coronavirus patients.
"This drug, dexamethasone can now be made available across the NHS."
British Prime Minister Boris Johnson welcomed the good news on Tuesday, and said the drug had been approved for use in the state-run health service and that the U.K. quickly stockpiled enough of the drug in the event of a second peak.
"It's an old drug. Some people would say it's a very boring drug. It's been around for 60 odd years. It's very cheap. It costs pounds and overseas cost pennies."
At the same briefing, the trial's co-lead investigator, Peter Horby, said the drug reduces mortality significantly.
"In patients on the ward who require oxygen and had COVID, it reduces the risk of death by about 20 percent. That covers about 75 percent of patients in the hospital who will receive a mortality benefit from using this drug. There's another group of patients who don't require oxygen but have COVID and we did not see a benefit in those patients. So it's not a drug that you would use in the community or in outpatients or in patients on the ward who didn't have breathing difficulties; but in patients with breathing difficulties, who require oxygen or ventilation, it really is showing quite a significant effect."
There are currently no approved treatments or vaccines for COVID-19, the disease caused by the new coronavirus which has killed more than 431,000 people globally.
The dexamethasone trial was launched in April as a randomized clinical trial to test a range of potential treatments for COVID-19, including the malaria drug hydroxychloroquine.
Testing of that drug was halted this month after the trial's lead investigators said results showed it was "useless" at treating COVID-19 patients.
"I can't complain about it. I took it for two weeks and I'm here. Here we are. And we've had some great studies," said U.S. President Donald Trump about hydroxychloroquine on Monday. "All I know is that we've had some tremendous reports. I've had a lot of people tell me that they think it saved their lives... So, I don't know, but I took it and I felt good about taking it. I don't know if it had an impact. But it certainly didn't hurt me."
Dexamethasone is on the U.S. Food and Drug Administration's list of drugs in shortage, but several manufacturers, including the largest supplier to the United States, say it is available.