A rare side effect of fluoroquinolone (FQ) antibiotics is QT prolongation, which may result in serious arrhythmias. Most published comparative trials describe the relative risks among the drug class but do not focus on the incidence of serious arrhythmias. It is important for the prescriber to have a sense not only of relative risk but also of incidence to balance the risks against the other attributes of the individual members of the drug class. A review of English-language literature was performed to identify trials that provide data on the relative risk and, when able to be calculated, the incidence of adverse cardiac events among the commonly used FQs. Moxifloxacin had a several-fold higher risk of cardiac arrhythmias than levofloxacin or ciprofloxacin in randomized trials. However, the actual event rate was low in 2 of 3 studies. Given inconsistencies among the studies and the relative rarity of the events, the clinician need not base the choice of drug primarily on concern for a cardiac arrhythmia except in patients at the highest risk of such an event.
Keywords: QT interval; QT prolongation; fluoroquinolones; side effects; torsades de pointes.
© 2015, The American College of Clinical Pharmacology.