Ciprofl oxacin and the risk for cardiac arrhythmias: culprit delicti or watching bystander?

Torsades de pointes (Tdp) is a polymorphic form of ventricular tachycardia and a life-threatening event. A variety of non-cardiovascular drugs, including fluoroquinolone antibiotics, have been shown to possess arrhythmogenic properties. However, only 25 cases of ventricular tachycardia associated with the use of ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, and moxifloxacin have been reported in the United States between 1996 and 2000, with ciprofloxacin being involved in two cases. Thus, it has been argued that the arrhythmogenic property of ciprofloxacin may derive from its interaction with other potentially arrhythmogenic drugs. We report: (i) a case of torsades de pointes (Tdp) associated with oral ciprofloxacin in a patient with concomitant risk factors and (ii) a review of the literature on pharmacokinetic interactions involving ciprofloxacin resulting in cardiac arrhythmias.