Health Canada is concerned that some people may be directly buying and using chloroquine and hydroxychloroquine to prevent or treat COVID-19 without a prescription. Chloroquine and hydroxychloroquine may cause serious side effects, including serious heart rhythm problems. The risk of these side effects may increase at higher doses, or if the drugs are used in combination with other drugs, such as the antibiotic azithromycin. Patients should use these drugs only under the supervision of a physician.

HMC