An evaluation strategy for potential QTc prolongation with chronic azithromycin therapy in cystic fibrosis

Chronic azithromycin therapy is recommended for CF patients with persistent Pseudomonas aeruginosa colonization. Other macrolide antibiotics have been reported to cause QT prolongation, but cardiac effects of azithromycin have not been studied in pediatric populations. We analyzed changes in QTc interval after starting chronic azithromycin in a pediatric CF population. Adolescent males showed increased QTc intervals after initiation of therapy. Given the possible effects of azithromycin on the QTc interval, particularly in patients predisposed to cardiac events, we suggest that the QTc interval of CF patients should be monitored throughout the course of chronic azithromycin.