Researchers fear high doses of chloroquine ‘might be toxic’ for coronavirus patients
Researchers examining chloroquine (CQ), an antimalarial medication often suggested as a potential treatment for COVID-19, ended their study early over fears that patients were at an increased risk of significant heart complications. High dosages of CQ, the study’s authors observed, were “not sufficiently safe to warrant continuation of that particular study arm.”
The team’s research has been published on medRxiv, an online server for articles that have yet to receive a thorough peer review.
“In a unique pandemic situation, health professionals have to choose between offering medical assistance and generating and reporting reliable data, a dichotomy that compromises the generation of good quality evidence for clinical management,” wrote author Mayla Gabriela Silva Borba, Amazonas State University in Brazil, and colleagues. “Global recommendations for COVID-19 are being made based on unpowered studies, however, and due to the chaotic urgency, such drugs are being prescribed in a compassionate manner given the severity of this disease. CQ, despite being a safe drug used for more than 70 years for malaria, might be toxic in the dosages recommended by Chinese authorities.”
A bit of background
Researchers have been investigating the use of CQ and another antimalarial medication, hydroxychloroquine, on COVID-19 patients since the pandemic’s beginnings. The earliest studies showed promise, the authors explained, with the Health Commission of Guangdong Province recommending a CQ dose of 500 mg twice a day for 10 days to treat patients between the ages of 18 and 65 with “mild, moderate or severe pneumonia secondary to COVID-19, as long as there were no specific contraindications.” Different doses were then recommended by other entities, including some that included shorter treatments periods.
In March, the FDA issued an emergency use authorization (EUA) for the use of CQ and hydroxychloroquine in the treatment of COVID-19 patients. The drugs have sparked a bit of controversy since that EUA was published, with President Trump and others pushing for their use and some healthcare specialists observing that more research is still necessary. The American Heart Association (AHA), American College of Cardiology (ACC) and Heart Rhythm Society recently published a guidance urging caution when considering the treatment of COVID-19 with hydroxychloroquine and azithromycin if the patients have cardiovascular disease.
Clinical trial ended early over concerns
The Brazilian research team performed a double-blinded, randomized clinical trial including data from 81 COVID-19 patients. Each participant either received a total dose of 12 grams or a lower dose of 2.7 grams. The aim was to “comprehensively evaluate the safety and efficacy” of these two treatment options.
“Currently, there is no specific antiviral therapy recommended for coronavirus infections,” the authors wrote. “Few treatment studies have been carried out because most strains of human coronavirus cause self-limiting disease, and routine supportive care is usually effective. For past severe strains of coronavirus, outbreaks were scattered, thus not allowing timely clinical trials.”
Overall, the high dose was associated with “potential safety hazards” that included QTc prolongation, which increases the chance of a severe arrythmia. The arm of the study involving the higher dose was ended early due to concerns that these complications could continue and even get worse.
The team did note that no placebo was used in their research due to national guidelines out of Brazil. Another limitation was that the research occurred at a single facility. The team did note, however, that its findings could still help researchers learn more about this serious issue.
“Given the enormous global push for the use of CQ for COVID-19, results such as the ones found in this trial can provide robust evidence for updated COVID-19 patient management recommendations,” the authors wrote.
Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.