A large study has discovered no link between fluoroquinolone antibiotics and fatal cardiac arrhythmias in older people.

The findings fly in the face of previous research that prompted the FDA to issue heart safety warnings on the use of azithromycin.

Related story: Cardiac risks of macrolides not negligible

This latest review of data from more than two million courses of fluoroquinolone antibiotics found macrolide antibiotics were not associated with a higher 30-day risk of ventricular arrhythmia than nonmacrolide antibiotics.

The incidence rate of serious arrhythmias was 3.4 per 1000 person years among current fluoroquinolone users and 4.0 among current penicillin users.

Furthermore no differences in rates of serious arrhythmias were observed in subgroups such as people over the age of 65 or those with a history of cardiovascular disease.

These findings suggest that current warnings from the US Food and Drug Administration may be overstated, say the authors in their paper published in the CMAJ.