Cardiovascular Effects

Azithromycin and other macrolides can cause abnormal electrical activity in the heart that may lead to a potentially fatal irregular heart rhythm.73,106 Patients at particular risk for developing this condition include those with known risk factors such as existing QT interval prolongation, bradycardia, and those taking medications for the treatment of abnormal heart rhythm or arrhythmias. Increased risk of death from cardiovascular causes has been reported in persons treated with a 5-day course of azithromycin.144