Azithromycin (Zpack) and levofloxacin (Levaquin) carry higher arrhythmia and mortality 
risks than amoxicillin, according to an observational study in the 
Annals of Family Medicine. The FDA issued a cardiac warning on 
azithromycin in March 2013.

Researchers studied nearly 1.8 million U.S. veterans (mean age, 57) 
who received outpatient prescriptions for one of the three antibiotics 
from 1999 to 2012. On weighted analysis, the numbers of deaths by day 
5 of treatment per million antibiotics dispensed were 154 for 
amoxicillin, 228 for azithromycin, and 384 for levofloxacin. Patients 
receiving azithromycin had roughly a 50% increased risk for death and 
an 80% increased risk for serious arrhythmia, compared with those on 
amoxicillin. Risk increases were even greater for levofloxacin.

The researchers conclude: “There are usually multiple antibiotic 
choices available for older patients, especially those with cardiac 
comorbidities; physicians may consider prescribing medications other 
than azithromycin and levofloxacin.”

Annals of Family Medicine article