The antibiotic azithromycin (Zithromax and Zmax) is used to treat a variety of bacterial infections, including community-acquired pneumonia and skin infections. The Food and Drug Administration (FDA) has revised azithromycin's label after a review of two studies. The first, published in the May 17, 2012, issue of the New England Journal of Medicine, found a higher risk of cardiovascular death with azithromycin use than with use of other antibiotics. That risk decreased after the drug was discontinued. The second was conducted by the drug's manufacturer. That study assessed azithromycin's potential to produce changes in the heart's electrical activity, and azithromycin was found to prolong the QT interval, which can lead to cardiac arrhythmias, including potentially fatal torsades de pointes. Information regarding the QT study has been added to azithromycin's labeling.

Although the risk of QT prolongation is small, certain factors increase it:

* known prolongation of the QT interval

* a history of torsades de pointes

* congenital long QT syndrome

* bradyarrhythmias

* uncompensated heart failure

* the use of other drugs that prolong the QT interval

* proarrhythmic conditions-uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, or the use of class IA (quinidine, procainamide) or class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents

* older age

* cardiac disease

Nurses treating patients prescribed azithromycin should assess patients for these risk factors. To read the FDA Drug Safety Communication regarding azithromycin, go to http://1.usa.gov/16p7u2S.