Scientists in Brazil halted part of a study on a malaria drug presented as a possible treatment for coronaviruses after heart rhythm problems developed in a quarter of people given the higher of the two doses tested.
Chloroquine and a similar new drug called hydroxychloroquine were pushed by President Donald Trump after some preliminary tests suggested that the drugs could prevent the virus from entering cells.
But the drugs have long been known to have potentially serious side effects, including an alteration in heart rate that can lead to sudden death.
The Brazilian study, in the Amazon city of Manaus, planned to enroll 440 seriously ill COVID-19 patients to test two doses of chloroquine, but the researchers reported results after only 81 were treated.
A quarter of those affected with 600 milligrams twice a day for 10 days have developed heart rhythm problems, and trends suggest that more deaths are occurring in this group, so the scientists stopped this part of the study.
Scientists in Brazil halted part of a study of the malaria drug presented as a possible treatment for coronaviruses after heart rhythm problems developed in a quarter of people given the higher of the two doses tested . In the photo: a chemist in New Delhi, India, displays hydroxychloroquine tablets (AP Photo / Manish Swarup, File)
The other group received 450 milligrams twice a day on the first day and then once a day for four more days.
This is closer to what is attempted in other studies, including some in the United States.
It is too early to know whether this will prove to be safe or effective; the Brazilian study did not have a comparison group that received no treatment.
Only one study participant in Brazil had no signs of a virus in throat swabs after treatment, the researchers noted.
The results of the study in Brazil have been posted on a research website and have not yet been reviewed by other scientists.
To make matters worse, all of the patients in the study also received two antibiotics, ceftriaxone and azithromycin.
The latter can also have side effects on the heart. Trump touted the combination of hydroxychloroquine and azithromycin.
Brazilian President Jair Bolsonaro has also repeatedly praised the benefits of chloroquine and azithromycin without evidence.
He said at one point that he had heard reports of 100% effectiveness when administered in the correct doses, reduced tariffs to zero for the importation of drugs and, at the end of last month, military laboratories had announced an increase in their production of chloroquine.
In fact, the results of the hydroxychloroquine trials have been mixed.
The drug is already widely deployed in countries like South Korea and China, but data on its safety and effectiveness are still collected in these countries as well as in the United States.
As coronavirus cases in the United States continue to exceed 570,000, the search for an effective treatment is intensified with tests for hydroxychloroquine and remdesivir in the United States.
However, a recent global survey has revealed that hydroxychloroquine is not only the potential treatment most often used by doctors internationally, but also the one they thought most likely to be effective.
The failed trial in Brazil comes when the coronavirus itself can attack the heart.
The first evidence that the virus can be dangerous for the heart came from China, which, at the origin of the coronavirus, was the spokesperson for the patterns of the disease.
Nearly 20 percent of the 416 coronavirus patients hospitalized in a study there showed signs of heart damage.
And more than half of the patients with heart damage died during their hospitalization for a coronavirus. In comparison, only 4.5% of patients without heart damage died.
This month’s daily coronaviruses in the U.S. surpassed 1,000 every day except one
Not surprisingly, rates of heart damage from coronavirus were much higher in people who already had heart disease before they became infected.
But worryingly, patients without previous health conditions were the hardest hit by the heart damage they suffered during their infection with the coronavirus.
This small group of patients was at higher risk of dying from heart complications from the disease.
However, as with all facets of COVID-19, the elderly and those with underlying health conditions are also the hardest hit by its heart effects.
Doctors believe that inflammation triggered by the coronavirus, the potential ability of the virus to attack blood vessels and infect the heart itself, can trigger heart attacks or heart failure in patients with COVID-19.
The combination of the impact of the coronavirus itself on the heart and the potential of hydroxychloroquine to trigger cardiac arrhythmias could therefore be dangerous for patients.
But it may be that at a lower dose – an NIH trial gives patients two doses of 400 mg of drug on the first day of treatment, followed by 200 mg twice a day for the next eight days – the drug poses a risk lower heart rate.