A large new study of patients who received either azithromycin or amoxicillin found no increased risk of cardiac events associated with azithromycin, except among patients also taking medications that affect the electrical impulses of the heart, researchers reported this week in JAMA Network Open.In the retrospective cohort study, researchers from the University of Illinois at Chicago College of Pharmacy, the University of Pittsburgh School of Medicine, and the Veterans Affairs Pittsburgh Healthcare System analyzed data on more than 4.2 million patients who received a prescription for either azithromycin or amoxicillin from 2009 through Jun 30, 2015.