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Fatal heart complications halt Brazilian study of chloroquine in treating COVID-19

Published on 14/04/20 at 10:45am
Photo by Joegoauk Goa

A chloroquine study investigating its effects in treating the COVID-19 coronavirus in Brazil has been postponed for safety reasons.

It was discovered that taking a higher dose of the drug made some patients develop irregular heart rates that increased their risk of a fatal heart arrhythmia.

The study involved 81 patients who had been hospitalised in the city of Manaus and was uploaded for peer review on Saturday. Half the participants were given a dose of 450 milligrams of chloroquine twice a day for five days, while the rest were prescribed 600 milligrams for 10 days. After three days, the researchers started noticing heart arrhythmias in patients taking the higher dose. After 6 days, 11 patients had died which led to an immediate end to the trial.

Brazil’s national guidelines recommend the use of chloroquine in COVID-19 patients.

Drug safety experts said that this was further evidence that chloroquine and hydroxychloroquine can pose a significant harm to some patients.

Dr David Juurlink, the Head of the Division of Clinical Pharmacology at the University of Toronto, commented on the study and said: “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.”

The anti-malaria drug has been constantly touted by President Trump as a coronavirus treatment, and is currently being used in multiple countries to treat patients suffering with COVID-19.

However, there is not much evidence to show its effectiveness. The original evidence supposedly showing its effectiveness was study of 36 people in France, which alledgely cured 100% of the patients. However, the study’s author left out that six dropped out after the first six days and they died, were transferred to the ICU or couldn't tolerate the drug.

Since Trump first mentioned the drug on 19 March, there have been 76 cases of hydroxychloroquine abuse compared to 35 during this same period last year. 77% of these cases were non-toxic meaning most patients taking the drug inappropriately were not poisoned. 

The study from Brazil will convince many that the drug is not safe to use in many types of patients and can be fatal for people with heart problems or those taking anti-depressants.

Conor Kavanagh

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