Yesterday the U.S. Food and Drug Administration (FDA) issued a statement acknowledging a recent medical journal report which found an increased risk of cardiovascular death in patients taking azithromycin (Zithromax). This antibiotic comes in a pill form and is used in the treatment of several types of infection.
According to the study of patients on Zithromax, this cardiovascular death risk, as well as death from any cause, was higher than those treated with amoxicillin, ciprofloxacin, or no drug at all. The cardiovascular death risks for patients taking levofloxacin were similar to those associated with the use of Zithromax.
The New England Journal of Medicine article explains that researchers looked at 347,795 patients taking Zithromax over a five-day period. Bloomberg News reports that this research found that “85 of every 1 million treatment courses of the drug were associated with cardiac death,” which is over twice the death rate as the alternative antibiotic amoxicillin.
The FDA explains that Zithromax “belongs to a class of antibacterial drugs called macrolides, which have been associated with cardiovascular effects; specifically, prolongation of the QT interval.” The QT Interval is the measure of the time between the beginning of the Q wave and the end of the T wave in the heart’s electrical cycle. The prolongation of the QT interval can lead to potentially fatal abnormal heart rhythm issues, such as torsades de pointes.
In March 2012, the drug label for Zithromax was revised to include this QT interval prolongation risk. The FDA explains it is currently in the process of updating the drug labels for other macrolide antibiotics.
The FDA approves the use of Zithromax for the following conditions:
Zithromax is a Pfizer product which earned the company $453 million last year. Bloomberg reports that a spokeswoman for Pfizer, Joan Campion, said in an email that “We are thoroughly reviewing this observational study within the overall context of the data we’ve collected for more than two decades on Zithromax’s benefits and risks.”
The FDA warns patients not to stop taking Zithromax without first speaking to a healthcare professional. The public health agency also said they are looking at the results of this study and will release any new information that comes out of their review.