Side Effects of Zithromax, Azithromycin May Increase Risk of Death: Study

The popular antibiotic Zithromax, which is known generically as azithromycin, may double the risk of death due to heart problems, according to the findings of new research. 

In a study published this week in The New England Journal of Medicine (NEJM), researchers at Vanderbilt University’s School of Medicine found that the risk of cardiovascular death increased for users of azithromycin during the first five days they were prescribed the drug.

Azithromycin, which is most commonly known by the brand name Zithromax or “Z Pack”, is a widely used antibiotic that is part of a class of medications known as macrolides. Other medications that are part of the same class have previously been associated with an increase in the risk of sudden death due to heart problems.

Researchers looked at Tennessee Medicaid records that included more than 347,000 patients who took Zithromax or a generic equivalent, nearly 1.4 million who took no antibiotics, 1.3 million who too amoxicillin, 264,000 who took Cipro and 264,000 given Levaquin.

During the first five days after they were given the prescriptions, 2.5 times as many patients died from cardiovascular death while taking Zithromax than while taking amoxicillin. That number was also elevated for those who took Cipro, but was about equal with Levaquin.

Researchers indicate that there is a small absolute increase in cardiovasular deaths with azithromycin during the five days of treatment, which is most highest among individuals with a risk of cardiovascular disease.

There were 47 more deaths for every million people who took Zithromax than for those who took Amoxicillin. That number increased to 245 more deaths per million when the focus was specifically on patients already at risk for heart problems.

The study was conducted after a number of reports of heart rhythm problems among similar antibiotics. Zithromax has long been considered to have low cardiotoxicity.