TORONTO -- Health Canada is warning the public of the possible side effects of a drug that U.S. President Donald Trump once touted as a possible “game changer” for the treatment and prevention of COVID-19.

In the health advisory, Health Canada said it is concerned people may be purchasing chloroquine and hydroxychloroquine to treat or prevent COVID-19 and that the drugs should not be taken unless prescribed and under supervision of a physician.

Health Canada said that the drugs can lead to dizziness, fainting, seizures, liver or kidney problems, and a potentially fatal irregular heart rate. Anyone experiencing these symptoms after taking these drugs is being asked to call their physician immediately.

Chloroquine and hydroxychloroquine are approved in Canada to treat malaria, lupus and rheumatoid arthritis, but are not approved medications for COVID-19, though both are currently under clinical trial.

“To date, data from clinical trials are limited, and the results have not conclusively shown that any specific medications are effective against COVID-19,” Health Canada said in the advisory.

The U.S. Food and Drug Administration and the U.S. National Institute of Allergy and Infectious Diseases each issued similar warnings last week.

Trump has repeatedly touted hydroxychloroquine during his press briefings as a means of treating COVID-19, even going so far as to call it "one of the biggest game changers in the history of medicine” when combined with azithromycin.

In March, an Arizona man died and his wife was hospitalized after the two ingested chloroquine phosphate, a form of chloroquine that is not the same as the drug and is instead used to clean fish tanks.

Health Canada is also warning the public to be cautious when buying medications online, as some websites may be illegitimate.