Higher risk of cardiac arrhythmia and death with azithromycin and levofloxcin, compared with amoxicillin
Following the 2013 Food and Drug Administration warning on azithromycin use and the risk of potential fatal heart rhythms, researchers in South Carolina evaluate a national cohort of veterans receiving care at the Department of Veterans Affairs to investigate whether cardiac arrhythmia and mortality risks are observed in older male patients receiving azithromycin, amoxicillin and levofloxacin.
Analysis of more than 1.6 million unique antibiotic dispensations of amoxicillin (n = 979,380), levofloxacin (n = 201,798) and azithromycin (n = 594,792), showed a higher risk of death associated with azithromycin and levofloxacin therapies as compared with amoxicillin.
Specifically, the researchers found a short-course of azithromycin therapy was associated with statistically significant hazard ratios of 1.48 for mortality risks and 1.77 serious arrhythmia risks within the first five days of treatment. The risk of these events was not significantly increased for days six to 10, likely explained by the traditional 5-day dispensation of azithromycin.
Treatment with levofloxacin, also when compared with amoxicillin, had statistically significant hazard ratios of 2.49 for mortality risk and 2.43 for serious arrhythmia risk; however, the increased risk with levofloxacin continued to be statistically significant during days six to 10. Levofloxacin, they note is predominantly dispensed for a minimum of 10 days.
These results, the authors conclude, provide support for the FDA’s recent safety announcement. They caution physicians to carefully consider the risks and benefits of antibacterial therapies when making prescription decisions.
By Gowtham A. Rao, MD, PhD, MPH, et al University of South Carolina, Columbia
Annals of Family Medicine: March/April 2014