A coronavirus drug trial was halted early in Brazil after hospitalized patients receiving high doses of chloroquine developed irregular heart rates known to cause sudden cardiac death.
Chloroquine and its sister drug hydroxychloroquine have been touted by President Trump and his allies as possible coronavirus treatments. Studies so far have shown scant evidence, if any, that the anti-malaria drugs curb COVID-19.
The Brazilian study, posted on medRxiv for peer review, said researchers prematurely halted enrollment in the portion of the 81-person study involving high doses of of chloroquine (CQ) because they noticed “potential safety hazards.”
“We found that a higher dose of CQ for 10 days presented toxicity red flags, particularly affecting QTc prolongation,” the study authors said.
QTc prolongation is a heart rhythm disorder that can be fatal.
“The trend towards higher fatality associated with the higher dose by day 6 of follow-up resulted in a premature halting of this arm,” the study that involved hospitalized patients in the Brazilian state of Amazonas said.
The study was broken down into two groups. One group was slated to receive 600 milligram doses of chloroquine twice daily for 10 days and the other group was due to receive 450 milligram doses twice on the first day and then once a day after that.
By the sixth day, 11 of the 81 total enrolled patients had died.
The trial also gave patients azithromycin, an antibiotic also known to prolong QTc intervals.
Last month, the Food and Drug Administration granted emergency approval to the Trump administration’s plan to distribute millions of doses of hydroxychloroquine and chloroquine.
One concerned physician who spoke to the Daily News said hydroxychloroquine has the potential to cause life-threatening abnormal heartbeats in 1% of patients.
If the drug is given to 1 million people, this “lethal dark side” could become significant.
“That’s 10,000 people standing close to the edge,” Dr. Michael Ackerman, a genetic cardiologist and director of Mayo Clinic’s Windland Smith Rice Sudden Death Genomics Laboratory, said.
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