A Comparative Study of the Fluoroquinolone Antibacterial Agents on the Action Potential Duration in Guinea Pig Ventricular Myocardia

We examined the effects of ten fluoroquinolone antibacterial agents, levofloxacin, sitafloxacin, trovafloxacin, ciprofloxacin, gemifloxacin, tosufloxacin, gatifloxacin, grepafloxacin, moxifloxacin and sparfloxacin, on action potentials recorded from guinea pig ventricular myocardia. Sparfloxacin prolonged action potential duration (APD) by about 8% at 10 μM and 41% at 100 μM. Gatifloxacin, grepafloxacin and moxifloxacin also prolonged APD at 100 μM by about 13%, 24% and 25%, respectively. In contrast, levofloxacin, sitafloxacin, trovafloxacin, ciprofloxacin, gemifloxacin and tosufloxacin had little or no APD-prolonging effect at concentrations as high as 100 μM. These findings suggest that there are differences in potency to prolong QT interval among the fluoroquinolones.