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, sita-floxacin, 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 μ M and 41% at 100 μ M. Gatifloxacin, grepafloxacin and moxifloxacin also prolonged APD at 100 μ M 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 μ M. These findings suggest that there are differences in potency to prolong QT interval among the fluoroquinolones.