Quoted from http://www.cbc.ca/news/health/story/2013/05/16/azithromycin-heart.html
Antibiotic Zithromax label to warn of potential heart side-effect
Health Canada says caution needed when treating patients with certain risk factors
The antibiotics Zithromax and Zmax SR (azithromycin) can cause potentially fatal irregular heart rhythms, Health Canada says.
Azithromycin is used for bronchitis, pneumonia, chest infections, urinary tract and other common infections.
Thursday's advisory from Health Canada says a "small absolute increase in the risk of cardiovascular deaths was observed in patients taking azithromycin as compared to those who took no antibiotics and those who took amoxicillin in a recent study."
In March, the U.S. Food and Drug Administration warned that the antibiotic, sold in Canada and the U.S. as Zithromax, can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm.
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