Arrhythmias associated with fluoroquinolone therapy.

Fluoroquinolones are widely used and well tolerated antibacterial agents. However, prolongation of the QT interval is an adverse effect associated with the use of fluoroquinolones. According to the available case reports and clinical studies, moxifloxacin carries the greatest risk of QT prolongation from all available quinolones in clinical practice and it should be used with caution in patients with predisposing factors for Torsades de pointes (Tdp). Although gemifloxacin, levofloxacin and ofloxacin are associated with a lower risk of QT prolongation compared with moxifloxacin, they should also be used with caution in patients with risk factors for QT prolongation. Ciprofloxacin appears to be associated with the lowest risk for QT prolongation and the lowest rate of Tdp. The overall risk of Tdp is small with the use of fluoroquinolones. Clinicians can minimise that risk by avoiding prescriptions of multiple medications associated with QT interval prolongation, especially in high-risk patients.