The new findings come two weeks after the Food and Drug Administration warned consumers against chloroquine or hydroxychloroquine to treat Covid-19 outside a hospital or formal clinical trial setting.
The agency said it became aware of reports of “serious heart rhythm problems” in patients with the virus who were treated with the malaria drugs, often in combination with antibiotic azithromycin, commonly known as a Z-Pak.
Hydroxychloroquine, which is available as a generic drug and is also produced under the brand name Plaquenil by French drugmaker Sanofi, can have serious side effects, including muscle weakness and heart arrhythmia. A small study in Brazil was halted for safety reasons after coronavirus patients taking chloroquine, which hydroxychloroquine is derived from, developed arrhythmia, including some who died.
Chloroquine was approved by FDA in 1949 to treat malaria. Hydroxychloroquine is often used by doctors to treat rheumatoid arthritis and lupus.
The study published Thursday is one of several looking at the drug as a potential treatment for the coronavirus, which has infected more than 1.2 million people across the United States, according to data compiled by Johns Hopkins University.
The New York State Department of Health, in partnership with the University of Albany, is conducting an observational study that researchers hope can shed some insight into the drug’s potential effectiveness. They are examining the medical records of Covid-19 patients who have been discharged from the hospital or have died to see what was prescribed and what may have been effective.
David Holtgrave, dean at the University of Albany’s School of Public Health and a researcher working with the state, told CNBC on Thursday that the study is not ready to be published but is nearing completion.
Observational studies aren’t considered as conclusive as randomized controlled trials because doctors can prescribe a variety of other drugs to treat an infection. The less formal process, however, can yield faster results and help with the approval process of some treatments.
There are no FDA-approved treatments for Covid-19 and U.S. health officials say a vaccine will take 12 to 18 months at the earliest.
Last week, the FDA granted emergency use authorization for Gilead Sciences’ antiviral drug remdesivir to treat Covid-19. The move came after the National Institute of Allergy and Infectious Diseases released results from its study showing Covid-19 patients who took remdesivir usually recovered after 11 days, four days faster than those who didn’t take the drug.