In two separate studies by the Department of Veterans Affairs and the American Medical Association, Hydroxychloroquine, the malaria drug touted as a coronavirus treatment by President Donald Trump, and Chloroquine, and older version of the drug, were found to not only have no benefit for coronavirus patients but to carry a significant risk of death.

Hydroxychloroquine, sold under several brand names such as Plaquenil by Sanofi‐Synthelabo Inc (SNY  ), is primarily used as part of treatment for malaria and lupus, among other conditions. The drug has been touted as a treatment for the coronavirus by President Trump. Still, many members of the medical community have been particularly skeptical about the benefits of the drug.

The study by the VA involved 368 patients in Veterans hospitals across the United States, the most extensive Hydroxychloroquine study to date. Of the 368 patients, 28% of those given Hydroxychloroquine died, while only 11% of those receiving routine treatment died. The drug was found to have no beneficial effect on patients and was found to have made no difference in the need for ventilation in severe cases either. Researchers found that the drug may have caused damage to internal organs during use.

The study conducted by the AMA found similar results during testing of Chloroquine. The findings cited a "primary outcome" of death, with the effects on patients being so dangerous that researchers cut the trial short. In the AMA study, conducted in Brazil, patients receiving the drug were found to have developed a heart rhythm disorder as a side effect of the drug. "One can only conclude from this trial that high-dose chloroquine (and by close association, hydroxychloroquine) in combination and azithromycin and possibly oseltamivir, is potentially associated with increased mortality among patients with severe, suspected COVID-19," said Dr. Stephan Fihn of Harborview Medical Center.

The studies conducted by the VA and AMA, along with reports of poisonings and death among users of the malaria drug, may have contributed to the FDA's decision to issue warnings on the use of Hydroxychloroquine and Chloroquine to treat coronavirus. The FDA's warnings mirror the findings of both studies, in that patients taking either drug, sometimes along with the common antibiotic azithromycin (commonly known by the brand name Z-Pak), suffered dangerous side effects.