Heart disease sufferers, take note: Recent studies have shown that the antibotic azithromycin — which is also known as Z-Pak — has been linked to a few rare cases of heart death. For every million azithromycin treatments, there have only been an estimated 47 deaths related to the prescription drug. Although the risk is relatively small, it’s something to think about should heart disease run in your family.

“It’s a small risk. And if you look carefully, you’ll see that all antibiotics have serious risks. For most patients, this is a relatively small risk,” ” study leader Wayne A. Ray, PhD told WebMD.

Not surprisingly, there’s another side to the story. According to Dr. Jay Varkey, MD, director of the antibiotic management program at Emory University, the study isn’t entirely conclusive. “In and of itself, this study does not warrant a dramatic amount of alarm. It calls for more studies to see whether the increased death rate was truly due to azithromycin or to the underlying disease being treated.” Fair enough.

The study, which followed patients on medicare who took the drug between 1992 and 2006, showed that those who took a five-day run of antibiotic were more likely to die from heart death than those who did not. When compared to those who had taken like-minded medications such as amoxicillin, patients were twice as likely to have severe complications.

Regardless of which report you choose to side with, Ray’s study of azithromycin’s effects on those with heart problems has given doctors reason to think twice before prescribing the drug to those with a history of the disease.