By Alan Lyndon
A new study found that chloroquine should not be used in higher dosages to treat COVID-19 due to potential harm to patients, specifically fatal heart arrhythmia.
Chloroquine (CQ) and the related drug hydroxychloroquine (HCQ) are antimalarial drugs that have been highly promoted by the Trump administration as COVID-19 treatment but not yet proven as effective or entirely safe for patients.
The Brazilian study followed 81 COVID-19 positive patients and sought to compare two dosages of chloroquine — high dose CQ (600mg CQ twice daily for 10 days) or low dose CQ (450mg for 5 days, twice daily only on the first day).
After six days of treatment, 11 of the patients in the high dose regimen had died which led to the “immediate interruption of the high dose arm,” according to the authors, and all remaining patients were moved to the low dosage. Only two of the 11 deaths were over 75 years old.
“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,” Dr. David Juurlink, an internist and the head of the division of clinical pharmacology at the University of Toronto, told the New York Times.
The researchers said of the high dose that they “strongly recommend that this dosage is no longer used anywhere for the treatment of severe COVID-19, especially because in the real world older patients using cardiotoxic drugs should be the rule.”
In addition, all patients also received azithromycin although the authors “were not able to independently assess the toxic role of azithromycin because all patients were already using this antibiotic as per hospital protocol.”
The study was published Saturday on medRxiv, an online server for medical articles prior to peer review.