The U.S. Food and Drug Administration (FDA) has issued a warning that the antibiotic azithromycin (Zithromax or Zmax) can cause abnormal changes in the electrical activity of the heart that may lead to a potentially fatal irregular heart rhythm.
Patients at particular risk include those with known risk factors such as existing QT interval prolongation, low blood levels of potassium or magnesium, a slower than normal heart rate, or use of certain drugs used to treat abnormal heart rhythms, or arrhythmias, according to an FDA statement.
Azithromycin drug labels have been updated with information related to the risk of QT interval prolongation and torsades de pointes, a rare heart rhythm abnormality. Information has also been added regarding the results of a clinical QT study which showed that azithromycin can prolong the QTc interval.
Healthcare professionals should consider the risk of fatal heart rhythms with azithromycin when considering treatment options for patients who are already at risk for cardiovascular events. The potential risk of QT prolongation with azithromycin should be considered when choosing antibacterial drugs, the FDA noted. Alternative drugs in the macrolide class, or nonmacrolides such as the fluoroquinolones, also have the potential for QT prolongation or other significant side effects that should be considered when choosing an antibacterial drug.
