Small Chloroquine Study Halted Over Risk of Fatal Heart Complications

“To me, this study conveys one useful piece of information, which is that chloroquine causes a dose-dependent increase in an abnormality in the ECG that could predispose people to sudden cardiac death,” said Dr. David Juurlink, an internist and the head of the division of clinical pharmacology at the University of Toronto, referring to an electrocardiogram, which reads the heart’s electrical activity.

Roughly half the study participants were given a dose of 450 milligrams of chloroquine twice daily for five days, while the rest were prescribed a higher dose of 600 milligrams for 10 days. Within three days, researchers started noticing heart arrhythmias in patients taking the higher dose. By the sixth day of treatment, 11 patients had died, leading to an immediate end to the high-dose segment of the trial.

The researchers said the study did not have enough patients in the lower-dose portion of the trial to conclude if chloroquine was effective in patients with severe disease. More studies evaluating the drug earlier in the course of the disease are “urgently needed,” the researchers said.

Several clinical trials for chloroquine and hydroxychloroquine are testing low doses for shorter periods of time in coronavirus patients. But the Health Commission of Guangdong Province in China had initially recommended those sick with the virus be treated with 500 milligrams of chloroquine twice daily for 10 days.

One of the authors of the Brazilian study, Dr. Marcus Lacerda, said in an email on Sunday that his study found that “the high dosage that the Chinese were using is very toxic and kills more patients.”

“That is the reason this arm of the study was halted early,” he said, adding that the manuscript was being reviewed by the journal Lancet Global Health.

Article source: https://www.nytimes.com/2020/04/12/health/chloroquine-coronavirus-trump.html