FDA Issues Zithromax Heart Safety Warnings
On March 12, 2013 The U.S. Food and Drug Administration (FDA) issued a drug safety warning about the popular oral antibiotic azithromycin, which goes by the trade names Zithromax or Zmax. The FDA warned that azithromycin can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm. Patients at particular risk for developing this condition include those with known risk factors such as existing QT interval prolongation, low blood levels of potassium or magnesium, a slower than normal heart rate, or use of certain drugs used to treat abnormal heart rhythm.
The FDA announced that the manufacturers of Zithromax and Zmax have updated their product labels, strengthening the Warnings and Precautions section with information related to the risk of QT interval prolongation and torsades de pointes, a specific, rare heart rhythm abnormality. Information has also been added regarding the results of a clinical QT study which showed that azithromycin can prolong the QTc interval.
The FDA announcement comes as a follow-up to an announcement the FDA made following a May, 17 2012 New England Journal of Medicine (NEJM) study that compared the risks of cardiovascular death in patients treated with the antibacterial drugs azithromycin, amoxicillin, ciprofloxacin (Cipro), and levofloxacin (Levaquin), or no antibacterial drug. That study reported an increase in cardiovascular deaths, and in the risk of death from any cause, in persons treated with a 5-day course of azithromycin (Zithromax) compared to persons treated with amoxicillin, ciprofloxacin, or no drug. The risks of cardiovascular death associated with levofloxacin treatment were similar to those associated with azithromycin treatment.
For more information, see the FDA’s drug safety communication at: FDA Drug Safety Announcement
For details of the original study that prompted the FDA to look further at its data on Zithromax, see the abstract at the New England Journal of Medicine: Ray, et al abstract