August 15th, 2012

Azithromycin & Levofloxacin May Increase The Risk of Cardiovascular Death

A study released in May 2012 in The New England Journal of Medicine found that azithromycin (ZITHROMAX, ZMAX) and levofloxacin (LEVAQUIN), two widely used antibiotics, may increase the risk of cardiovascular death.

Based on an examination of the medical records of 3.5 million Tennessee Medicaid patients, those who took azithromycin (distributed commonly as the five-day “Z-pak”) were almost three times more likely to die from cardiovascular causes, such as sudden cardiac death, during the five days of therapy than those who took no antibiotics and 2.5 times more likely to die from cardiovascular causes than those who took amoxicillin (AMOXIL), another antibiotic. This translated to 47 to 245 more cardiovascular deaths for every 1 million patients placed on the drug (relative to amoxicillin users).

Levofloxacin was associated with a 50 percent increased risk of cardiovascular death compared to the risk in those who took amoxicillin, although the results for levofloxacin were less clear than those for azithromycin.

Based on this research and previous studies, both azithromycin and levofloxacin are thought to cause a heart rhythm disturbance known as torsades de pointes, which can lead to sudden cardiac death, the most common cause of death in azithromycin users in the recent NEJM study.