Specifically, the FDA is warning that Azithromycin, sold as Zithromax (Z-Pak) and made by Pfizer, can cause a potentially fatal irregular heart rhythm in some patients. The agency is basing it’s statement on a study by medical researchers as well as a company study assessing the drug’s potential for causing abnormal changes in the electrical activity of the heart.
The New England Journal of Medicine compared the risk of cardiovascular death in patients who took Zithromax with those who took several other antibiotics, including amoxicillin. It found that patients who took Zithromax had higher rates of fatal heart issues.
How does this drug cause hearth problems? According to research, it can alter the electrical activity of the heart, which may lead to a potentially fatal heart rhythm known as prolonged QT interval, in which the timing of the heart’s contractions becomes irregular.