Zithromax and risk of cardiovascular death

This past May, the FDA notified healthcare professionals that it is aware of the study published in the New England Journal of Medicine (May 17) reporting a small increase in cardiovascular deaths and in the risk of death from any cause in persons treated with a 5-day course of azithromycin (Zithromax) compared to persons treated with amoxicillin, ciprofloxacin, or no drug. The FDA is reviewing the results from this study and will communicate any new information on azithromycin and this study or the potential risk of QT interval prolongation after the agency has completed its review.

The concern arose when Vanderbilt University researchers analyzed health records and data on millions of prescriptions for several antibiotics given to about 540,000 Tennessee Medicaid patients from 1992 to 2006. During that period, there were 29 heart-related deaths among those who took Zithromax during five days of treatment. Their risk of death while taking the drug was more than double that of patients on another antibiotic, amoxicillin, or those who took none. By calculating the number of deaths per 1 million courses of antibiotics, there would be about 85 among patients taking Zithromax, versus 32 among those taking amoxicillin and 30 among those taking no antibiotics. It appeared that the highest risks were in Zithromax patients with existing heart problems. Patients studied were age 50 on average, not hospitalized, and with comparable cardiac risks factors. Most were taking antibiotics for common ailments, including sinus infections and bronchitis.

RECOMMENDATION: Patients taking azithromycin should not stop taking their medicine without talking to their healthcare professional. Healthcare professionals should be aware of the potential for QT interval prolongation and heart arrhythmias when prescribing or administering any macrolide antibiotic.