Chloroquine or hydroxychloroquine (HCQ), with or without an antibiotic, in hospitalized COVID-19 patients were associated with increased risk of death in the hospital and higher rates of arrhythmias, analysis of outcomes in almost 100,000 patients indicated.
As part of the trial, 40,000 healthcare workers from four continents will be given chloroquine, hydroxychloroquine, or a placebo.
The drugs are approved for treating lupus and rheumatoid arthritis and for preventing and treating malaria, but no large rigorous tests have found them safe or effective for preventing or treating COVID-19.
The study was published Friday in the medical journal The Lancet and detailed in a report by The Washington Post. It is known that the drug can cause heart irregularities, but many have claimed it is safe because of its long use treating malaria. People sick enough to be hospitalized with the coronavirus are not the same as healthy people taking the drugs in other situations, so safety can not be assumed from prior use, Mehra said.
Trump said this week that he's taking hydroxychloroquine in an effort to ward off the coronavirus.
"An association of increased overall mortality was identified in patients treated with hydroxychloroquine alone", the researchers wrote.
A Wisconsin woman has taken the unproven coronavirus drug hydroxychloroquine for almost two decades for another health condition - and says she was still infected by the virus, according to a report.
Professor Landray said thousands of lives could be saved if a drug could reduce fatalities even by one fifth, however he believes that combination therapies may be needed. The death rate among patients not taking the drugs was one in 11.
The statistics are not exactly comparable because, as this was not a trial, there were differences in the age, gender, general health and stage of illness of the patients. "The fever was very high", Kim said. The risk of developing a serious heart rhythm problem is more than five times greater.
They compared the outcomes for almost 15,000 patients who had been treated with chloroquine or hydroxychloroquine - either alone or in combination with antibiotics - with more than 81,000 patients who had not been treated with any of those drugs.
"This is the first large scale study to find statistically robust evidence that treatment with chloroquine or hydroxychloroquine does not benefit patients with COVID-19", he said. "Instead, our findings suggest it may be associated with an increased risk of serious heart problems and increased risk of death".
"We were unable to confirm a benefit of hydroxychloroquine or chloroquine, when used alone or with a [an antibiotic], on in-hospital outcomes for COVID-19".
It said the drugs should not be used outside ongoing clinical trials which have reached no conclusions over the safety and effectiveness of the medicine on coronavirus. A study of 368 US veterans also showed that the drugs might be potentially harmful.
"It should not be used in the general population to prevent or to treat Covid-19 infection".
Even though it is only observational, the size and scope of the study gives it a lot of impact, said Dr. David Aronoff, infectious diseases chief at Vanderbilt University Medical Center.