The double-blinded study was meant to assess the safety and effectiveness of two different chloroquine dosages in patients hospitalized with COVID-19 at Hospital e Pronto-Socorro Delphina Rinaldi Abdel Aziz in Manaus.
Patients in one group received 600 milligrams of the drug daily for 10 days while another group was getting 450 milligrams for five days, twice daily for the first day and once daily for the following days. All patients also received azithromycin, an antibiotic, along with chloroquine, which has traditionally been used against malaria, lupus, and several other illnesses.
Out of 440 patients identified, 81 hospitalized patients were enrolled. About half were given the high dosage and the others were given the lower dosage.
Researchers said they began noticing heart issues in patients taking the higher dose within three days and by the sixth day, 11 patients had died, prompting the premature halting of that arm.
“High dosage of chloroquine in critically-ill patients with COVID-19 needs to be stopped now,” Marcus Lacerda, one of the researchers, who works at the Fundação de Medicina Tropical, told The Epoch Times in an email.
Researchers wrote in the study that preliminary findings suggest against high dosage of chloroquine “because of its potential safety hazards,” adding, “Such results forced us to prematurely halt patient recruitment to this arm.”
The lower-dosage arm of the study is still ongoing, Lacerda confirmed.
The article is preprint and has not been peer reviewed. It was submitted to JAMA on Monday.
Chloroquine and the closely related hydroxychloroquine have been widely touted as effective against COVID-19 across multiple countries but some recent research suggests the need for doctors to be cautious in what doses they give and which patients they choose to treat with the unproven treatments.
Dozens of heart incidents were linked to hydroxychloroquine in patients given the drug, French officials said last week.
Little research has come out yet for chloroquine and hydroxychloroquine but preprint studies in France and at least one study in China suggested the drugs can be effective against COVID-19, the disease caused by the CCP (Chinese Communist Party) virus, commonly known as novel coronavirus.
Multiple clinical trials are ongoing in the United States and other countries. South Dakota announced Monday it was launching the first state-wide trial of hydroxychloroquine in the nation and New York Gov. Andrew Cuomo said initial results from a study there are expected next month.