Rates of Torsades des Pointes Associated With Ciprofloxacin, Ofloxacin, Levofloxacin, Gatifloxacin, and Moxifloxacin [Frothingham R et al. Pharmacotherapy 2001;21:1468]: The authors evaluated the reported rates of torsades de pointes in patients who received fluoroquinolones between 1996 and 2001. During this time there were 25 cases reported including ciprofloxacin-2, ofloxacin-2, levofloxacin-13, gatifloxacin-8 and moxifloxacin-0. The rates based on prescriptions are provided in the following table based on number of reported cases/10 million prescriptions:

Rates of Torsades de Pointes

Quinolone Rate

(per 10 million prescriptions)

Moxifloxacin 0.0

Ciprofloxacin 0.3

Levofloxacin 5.4

Gatifloxacin 27.0

Comment: Prolongation of the QT interval is a rare but potentially serious complication associated with multiple drugs including some fluoroquinolones. The conclusion of the authors in this report is that levofloxacin should be given with caution in patients with risk factors for QT prolongation and gatifloxacin should be avoided in this patient population and the recommended dose of 400 mg/day should not be exceeded.

By John G. Bartlett, M.D., posted 03-08-2002