The effects of levofloxacin on ECG parameters and late potentials

In this study, our aim was to investigate the proarrhythmic effects of levofloxacin. Twenty-six patients who were diagnosed as having community-acquired pneumonia were enrolled in the study. Intravenous levofloxacin, 500 mg daily, was given, and 12-lead ECG measurements were obtained before the infusion, at 30 and 60 minutes during infusion, and 10 minutes after its cessation. Resting late potentials were recorded before and after infusion. Twelve female and 14 male patients were participated the study. Mean age was 51.3 +/- 22.3 years. Levofloxacin infusion increased the heart rate (HR) and prolonged the corrected QT (QTc) intervals significantly (baseline HR: 84.6 +/- 18.8 vs. HR at 60 minutes: 88.6 +/- 18, P = 0.02; baseline QTc: 413.5 +/- 36.9 milliseconds vs. QTc at 60 minutes: 426.1 +/- 34.7, P = 0,006). There was no significant difference between the late potential values obtained before and after infusion. None of our patients experienced severe arrhythmia that required stopping the treatment. A single dose of IV levofloxacin prolongs the QTc interval without significant change in late potentials. Monitoring ECG during levofloxacin infusion might be necessary in patients who have a condition that could affect the QTc interval.