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  • Canada’s drug regulator is warning against unprescribed use of drugs to treat COVID-19
  • These drugs can cause side effects and should only be taken under a doctor’s supervision
  • Health Canada has not approved any drugs to prevent, treat or cure COVID-19

Chloroquine (CQ) and hydroxychloroquine (HCQ) are approved in Canada for the treatment of malaria and certain autoimmune disorders. Both drugs can cause a wide range of side effects (detailed later in this bulletin) but perhaps the most serious is that they can cause abnormal heart rhythms, which may become fatal in some people. Health Canada notes that “children are especially sensitive to these drugs, and even small doses taken by children can be dangerous.”

Health Canada is concerned that some people may be buying CQ or HCQ in the hope of preventing or treating COVID-19. The Ministry states: “Use chloroquine or hydroxychloroquine only if it has been prescribed for you by a physician who is supervising your treatment. Contact your physician if you experience an irregular heart rate, dizziness, fainting, seizures or other side effects while taking these drugs.”


There are many drugs being tested in clinical trials in Canada and other countries for the treatment of SARS-coronavirus-2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). As COVID-19 is a recent and ongoing pandemic, and these clinical trials are still underway, Health Canada has not approved any drugs, including CQ or HCQ, for the prevention or treatment of COVID-19.

Health Canada states that “results from large, well-designed studies are essential to determine if the benefits of CQ or HCQ outweigh their risks in the treatment of COVID-19. To date, data from clinical trials are limited, and the results have not conclusively shown that any specific medications are effective against COVID-19.”

Advice for patients

Health Canada has provided the following guidance:

Advice for healthcare providers

Health Canada has provided the following guidance:

Investigational use of approved therapies such as hydroxychloroquine and chloroquine should be done in the context of a well-designed clinical trial.

Consult the Canadian product monographs for a full list of contraindications, warnings and precautions, adverse reactions and drug interactions.

Monitor patients closely if treated with chloroquine or hydroxychloroquine, especially in the following situations:

  • if there are pre-existing heart conditions
  • when using higher doses
  • if prescribing in combination with other medications, such as azithromycin, that may cause [an abnormal heart rhythm detected with cardiograms; this abnormality has the technical term prolonged QT interval]

More about CQ and HCQ

As CQ and HCQ have the potential for a range of harmful effects, careful clinical and laboratory monitoring is needed when these drugs are used. Some side effects associated with these drugs in the past are as follows:

  • abnormal heart rhythms – these can increase the risk for heart failure, particularly when the antibiotic azithromycin is used. In such cases, CQ or HCQ could increase the risk for highly abnormal heart rhythms and sudden cardiac death.
  • metabolic issues – low blood sugar can cause fatigue, sweating, irregular heartbeats and, in severe cases, blurred vision, confusion and seizures
  • brain and behaviour – CQ and HCQ can cause a wide range of unusual behavioural side effects in people with and without a history of mental health issues. These side effects can include agitation, confusion, depression, hallucinations, paranoia, sleeping problems, psychosis and thoughts of self-harm

These effects can occur with short- and long-term use.


Kaletra disappointing in people severely ill with COVID-19CATIE News

Coronavirus disease (COVID-19): Outbreak update – Public Health Agency of Canada

COVID-19 resources

COVID-19: What people with HIV should knowUS Centers for Disease Control and Prevention (CDC)

Interim guidance for COVID-19 and persons with HIVUS Department of Health and Human Services

—Sean R. Hosein


  1. Health Canada. Chloroquine and hydroxychloroquine can have serious side effects. These drugs should only be used under the supervision of a physician. Recalls and Safety Alerts. 25 April 2020. Available at: https://www.healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2020/72885a-eng.php
  2. Juurlink DN. Safety considerations with chloroquine, hydroxychloroquine and azithromycin in the management of SARS-CoV-2 infection. CMAJ. 2020; in press.