This week the FDA renewed a warning it had first sounded last year about the antibiotic azithromycin. But it wasn’t just a reminder that the drug, whose brand name is Zithromax, or Zmax, carries risks-this was a graver assessment that azithromycin can cause the heart’s electrical rhythms to change which, for some people, can be fatal.
As widely noted in the media, including the New York Times, the initial warning came on the heels of research published in the New England Journal of Medicine (NEJM) last spring. Since then, warning labels have been included on the drug’s packaging, and the FDA has been reviewing the study.
The data showed a modest increase in the likelihood of death in people with a five-day course of azithromycin compared with patients treated with other antibiotics including amoxicillin (Amoxil) and ciprofloxacin (Cipro, Proquin).
As The Times notes, azithromycin was believed to be safer than a couple of other related antibiotics, erythromycin (Erythromycin) and clarithromycin (Biaxin), which also can raise the risk of death. But it has leapfrogged those drugs in concern over heart problems. The new, more serious FDA warning says patients at risk of the heart arrhythmia include the elderly and those with a history of heart problems, low blood levels of potassium or magnesium, slow heart rates and anyone taking medication that slows the heart rate.
People typically are prescribed azithromycin for bacterial infections such as bronchitis and pneumonia, sore throats and earaches. Commonly called “Z-Pak,” it’s taken for five days, which most people find preferable to many other antibiotics that must be taken for twice as long.
If you are taking azithromycin or if your doctor prescribes it, ask about the cardiac risks of the drug. Ask if any other drugs you take slow your heart rate. Ask if another antibiotic in the same class (macrolides), or a different class, such as fluoroquinolones (levofloxacin, moxifloxacin, norfloxacin) can be substituted for azithromycin. Like all drugs, they, too have potential risks and side effects, but do not present the cardiac risks of azithromycin.
*This post was edited to correct the distinction of antibiotic classes.