Doctors are cautioning that using hydroxychloroquine to treat coronavirus may be dangerous after more than 90 percent of COVID-19 patients in two studies of the drug developed signs of dangerous heart arrhythmias.
If heart rhythms remain irregular for too long, it can trigger heart attack and stroke.
Heart arrhythmias are a known and potentially life-threatening side effect of the malaria and lupus drug touted by Trump, so researchers in the US and France carefully monitored 90 and 40 patients, respectively, for them.
Each found that more than 90 percent of coronavirus patients in ICUs showed longer-than-normal delays between heartbeats, a worrisome sign that the drug might be disrupting their cardiac function.
In an accompanying editorial in JAMA Cardiology, Northwestern University cardiologist Dr Robert Bonow warned that once these signs emerge, ‘allowing treatment beyond these limits…in patients with COVID-10 should not be recommended unless there are clear benefits associated with anti-inflammatory or antiviral effects that are yet to be clinically demonstrated.’
Doctors, patients and President Trump looked to hydroxychloroquine with optimism after a French study suggested it had drastically improved survival rates and recovery times for coronavirus patients.
The FDA gave emergency use authorization for doctors to try the drug for US coronavirus patients, although the journal that published the French study later said the research did not meet the publication’s standards.
Nonetheless, trials, off-label uses, hoarding and internet searches for hydroxychloroquine surged in the US and around the world.
‘Among possible therapies, hydroxychloroquine has been advocated and even politicized as a promising therapy because of its anti-inflammatory and potential antiviral properties,’ Dr Bonow noted in his editorial.
‘The drug, known for its immunosuppressive and antimalarial effects, has risen to the top of many treatment algorithms alone or in combination with azithromycin.’
In lab studies, the drug, approved by the Food and Drug Administration (FDA) in 1955, appeared to have antiviral qualities, and the possible ability to bat back out of control inflammation thought responsible for the deaths of many coronavirus patients.
But the drug is not without its own dangers.
Although it’s used to treat malaria and autoimmune conditions like lupus and rheumatoid arthritis, hydroxychloroquine may throw off the process that makes the heart beat in time.
One trial in Brazil was stopped short because so many of the enrolled coronavirus patients being treated with the drug developed these arrhythmias.
In order to try to quantify when, why and how frequently this was happening, researchers at Massachusetts General Hospital in the US and the University of Lyon in France closely monitored so-called QT intervals in critical coronavirus patients treated with hydroxychloroquine.
The QT interval measures, in effect, the time that passes between when the heart’s ventricular muscle contracts and then relaxes.
When this interval becomes too long, the patient has developed a dangerous form of heart arrhythmia, called atrial fibrillation – the same condition that Apple Watches have been hailed for catching, saving the lives of their wearers.
It’s also one of the leading reasons that patients are advised to stop taking a given medication.
A normal QT interval lasts between 400 and 440 milliseconds (men have shorter QT intervals than women).
In the French study, a quarter of the patients had QT intervals that lasted 60 milliseconds too long or more and 18 percent had intervals lasting 500 milliseconds or longer.
Out of the 40 patients in the study, 37, or 93 percent, experienced prolonged QT levels.
In the Mass Gen study, 20% of the 90 patients treated developed QT levels that lasted or exceeded 500 milliseconds. Of those, 30 were being treated in ICUs, suggesting they were already in fragile conditions.
Taken together, more than 90 percent of the combined 130 patients had longer-than-normal QT intervals. Some developed such dangerous heart arrhythmias that treatment was stopped early.
It’s particularly worrisome now that doctors think coronavirus may attack the heart and cardiovascular system, either by infecting the tissue (called cardiomopathy), triggering clots by damaging blood vessels or via the inflammation the virus causes.
Dr Bonow notes that acutely ill patients like most of those treated in the two studies may be at greater risk of heart arrythmias due to other factors.
He also writes that it’s possible that in some scenarios the potential benefit of hydroxychloroquine – once established by further studies – may outweigh the risk of arrhythmias.
That sentiment is reflected on the American College of Cardiology’s website about the experimental use of hydroxychloroquine to treat COVID-19 patients: ‘While QT-prolonging medication use has been associated with increased risk of death, this risk may be smaller than the potential benefit from treatment of COVID-19 for some patients.
‘Currently, there is hope for benefit from hydroxychloroquine, yet there is little evidence. That is likely to rapidly change, given many pending clinical studies.’
In his editorial, Dr Bonow does not advise that clinical trials of the drug stop, but warns they should proceed with caution.
‘Understanding whether this risk is worth taking in the absence of evidence of therapeutic efficacy creates a knowledge gap that needs to be addressed,’ he writes.
‘Whether signals of potential benefit outweigh signals of harm is unknown until well controlled clinical trials are completed for the treatment or prevention of COVID-19 infections.’
He adds that availability of alternative potential treatments will also play into this calculus, which may be altered by the encouraging early results of trials of remdesivir announced this week.
Source: Dailymail.co.uk