Over time there have been studies with conflicting results as to whether azithromycin use is associated with an increased risk of adverse cardiac effects.

The FDA issued a warning cautioning against the use of azithromycin in patients with known cardiac risk factors such as long QT syndrome, electrolyte abnormalities and Torsades de pointes based on a 2012 study by Ray et al.

Patel et al recently published their study in JAMA Network Open which was a retrospective cohort study of a database of outpatient prescriptions dispensed. New users of azithromycin were compared to new users of amoxicillin (which is known not to cause cardiac adverse events). More than 2 million episodes of azithromycin use were matched to episodes of amoxicillin use.

The odds of a cardiac event with azithromycin were not significantly higher than with amoxicillin irrespective of patient age or the existence of other risk factors. However, the odds ratio was significantly higher in patients on other drugs known to prolong the QT interval and the authors recommend avoiding the use of azithromycin in patients who are taking other QT interval-prolonging drugs.

You can find the full article at JAMA Network Open.