Health

Canadian doctors urge caution on repurposing malaria medication to fight COVID-19

Combining the malaria drug hydroxychloroquine with an antibiotic to fight COVID-19 needs to be put to a true scientific test to determine its safety and effectiveness, doctors caution.

Canada part of a global study launched by the WHO to look into the use of chloroquine and other existing drugs

An employee checks the production of chloroquine phosphate at a pharmaceutical plant in east China's Jiangsu province in February. The drug, which treats malaria, has shown some efficacy against COVID-19-associated pneumonia in early research, but more study is required, experts say. (Barcroft Media/Getty Images)

Canada's top public health doctor warned against using malaria medication to treat COVID-19 on Monday, after U.S. President Donald Trump touted the option during a recent news conference.

People have taken chloroquine to prevent and treat malaria for decades. A related medication called hydroxychloroquine is mainly used to treat inflammatory disorders such as rheumatoid arthritis and lupus.

There are currently no approved treatments or vaccines for COVID-19. People in more than 180 countries have been sickened by the respiratory illness caused by a coronavirus humans have no immunity against.  

Last week, Trump told reporters hydroxychloroquine had shown "very, very encouraging early results." But Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, was also quick to say that officials are trying to strike a balance between making the potential therapy available to physicians to use on seriously ill COVID-19 patients on an emergency basis while ensuring it is truly safe and effective through clinical trials. 

On Monday, Dr. Theresa Tam, Canada's chief public health officer, added her own cautions.

"My message is that you should not take medication without the scientific evidence," Tam said. "It can be quite dangerous. These drugs are not without side-effects. In fact, there are quite significant side-effects."

The World Health Organization (WHO) is running a research network called Solidarity that has identified a "vast suite of potential drug therapies and combinations" that could be repurposed to treat COVID-19.

Tam said part of Canada's participation in the network includes making sure patients will receive drugs in the most scientific and safest way possible. 

Dr. Theresa Tam, Canada's chief public health officer, leaves a news conference Monday after cautioning against taking medications touted for COVID-19 treatment that aren't backed up by solid scientific evidence. (Blair Gable/Reuters)

Dr. David Juurlink, head of clinical pharmacology and toxicology at Toronto's Sunnybrook Health Sciences Centre, is writing a review on the safety of chloroquine and hydroxychloroquine. 

Trump suggested using hydroxychloroquine together with an antibiotic based on the results of a small study by French researchers. 

Juurlink said that study involved just 36 patients on using hydroxychloroquine and azithromycin as a treatment for COVID-19 — research with "so many holes you could drive a truck through it," he said. 

Normally, an antibiotic is never recommended to treat a virus. But the antibiotic and antimarlarial combination has off-target effects beyond what it was designed to do, infectious disease experts say.

Juurlink said he's concerned about possible toxic overdoses from chloroquine and hydroxychloroquine and side-effects such as:

  • Irregular heartbeat.
  • Low blood sugar.
  • Mood changes and psychosis.

"These are not drugs to be toyed with," Juurlink said.

In Arizona, a man died and his wife was hospitalized after taking a nonmedical form of chloroquine used to fight parasites in aquariums.
 
"Given the uncertainty around COVID-19, we understand that people are trying to find new ways to prevent or treat this 
virus, but self-medicating is not the way to do so," said Dr.  Daniel Brooks, medical director of the poison and drug 
information centre at Arizona-based Banner Health. 

Trial to protect hospital staff

The only way to tell if a treatment really works is to randomly assign a large number of patients to either take it or a placebo. Even then, rarer side-effects may not crop up until years later, once more people have taken the medication.

In the U.S. and Canada, doctors and pharmacists said hoarding hydroxychloroquine for COVID-19 could hurt others, such as those who take the drug long term to keep chronic inflammatory diseases like lupus under control.

Pharmaceutical companies in Canada and worldwide are donating hydroxychloroquine to help medical researchers collect high-quality data on the safety and effectiveness of using the medication to treat COVID-19.

Dr. Kevin Kain is an infectious disease physician at Toronto General Hospital, where he's part of a team of researchers designing a randomized placebo-controlled trial into the safety and efficacy of using hydroxychloroquine prophylactically to prevent COVID-19 infection. Their goal is to protect front-line health-care workers in emergency departments and intensive care by preventing the infection from taking root. 

"This seems like the appropriate, high-risk group to establish that it works," Kain said. "Right now, people are using it without good evidence. I was around long enough to remember SARS, where a number of treatments were tried without appropriate trials, and in retrospect, a lot of those things actually caused harm."

An undated electron microscope image shows SARS-CoV-2, the virus that causes COVID-19, orange, emerging from the surface of cells, green, cultured in the lab. Chloroquine seems to facilitate entry of zinc to kill the virus. (NIAID-RML/The Associated Press/The Canadian Press)

In the lab, chloroquine works by suppressing the growth of coronaviruses such as SARS and  SARS-CoV-2, the virus that causes COVID-19, the French researchers said.

"It isn't entirely clear, but there's intriguing evidence that if you can get high levels of a mineral called zinc … inside a cell that's infected, it will inhibit replication of coronaviruses," Kain said. "Taking a lot of zinc by mouth doesn't do this because getting zinc into a cell is tightly regulated. Chloroquine seems to facilitate it getting into the cell."

Elsewhere in the world, Doctors Without Borders is preparing to treat patients with COVID-19, potentially with chloroquine or hydroxychloroquine. The medical charity operates in more than 70 countries.

Jason Nickerson, humanitarian affairs adviser for Doctors Without Borders in Ottawa, said if a treatment stops the severe illness from COVID-19, then it would be incredibly beneficial, particularly in countries with less resourced health systems.

"How do we get these new technologies, once they're developed, to patients in all countries, everywhere?"

He called on governments worldwide to apply policies to ensure technologies like drugs that are developed with public funds remain affordable and globally accessible, since in a pandemic, the virus needs to be stamped out everywhere to protect people everywhere. 

With files from CBC's Vik Adhopia and Reuters

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