FDA Alert on Zithromax (azithromycin) Increased Risk of Deaths

May 18, 2012 — The FDA will be updating the label on Zithromax (azithromycin) to warn of the risk of cardiovascular death. The updates are in response to a study published in the New England Journal of Medicine.

Researchers found a slightly higher risk of cardiovascular death among patients who were taking the 5-day antibiotic treatment — approximately 64 deaths per million courses of treatment. Though the risk is small, the researchers recommended that doctors consider prescribing another type of antibiotic to high-risk patients.

Azithromycin belongs to the macrolide class of drugs, which is known to cause irregular heart rhythm. In March 2012, the FDA updated the label on all macrolides (including azithromycin) to warn that the medication can prolong the heart’s QT interval, leading to an irregular heart rhythm. Experts already know that a prolonged QT interval is a risk factor for cardiovascular death, and now, there is data to back up the increased risk of death with azithromycin.

The researchers based their conclusions on an analysis of data from 540,000 people. The population was located in Tennessee, between 30-74 years old, from the years 1992 through 2006. The researchers examined the rate of cardiovascular deaths among people while they were taking azithromycin, ciprofloxacin, or amoxicillin, and they compared this rate of death to a comparable period of time when the person was taking no drug.

Azithromycin was associated with an excess 64.6 deaths per million courses of treatment. During non-treatment periods, there were only 24 deaths. Although the increased risk of death is small, it is significant enough that doctors might want to consider prescribing other, safer antibiotics to people at high risk of cardiovascular deaths.

Risk factors for cardiovascular death include having diabetes, a history of heart attack or heart failure, or people who have a stent inside their heart or have already had open heart surgery.

Zithromax (azithromycin) is one of the most popular antibiotics in the world. It is well-known as the “Z-pack,” which is a 5-day regimen. Most other antibiotics are a 10-day regimen. Doctors typically prescribe azithromycin to treat bacterial infections, such as pneumonia or bronchitis. It is also frequently prescribed for sore throats and earaches. In the U.S., there were 55.3 million prescriptions written for azithromycin in 2011. Globally, sales topped $1.8 billion.