Azithromycin has been associated with prolongation of the QTc interval and development of torsades de pointes.

Previously, there were no data detailing the incidence of sustained ventricular tachycardia in patients with known prolonged QTc who were subsequently given azithromycin.

In a small cohort of patients admitted to a tertiary referral medical center, the risk of sustained ventricular tachycardia was less than 1 % in patients with prolonged QTc who subsequently received azithromycin.