Abstract: AIM: To compare the different medication regimens of levofloxacin in treatment of community-acquired pneumonia and provide evidence for clinical rational drug use.METHODS: Twenty-four adult patients with severe community-acquired pneumonia and receiving mechanical ventilation were assigned randomly into 2 groups (n=12) received 1-hour intravenous infusion of levotloxacin 500 mg once or twice daily respectively. The levotloxacin concentrations at steady-state in plasma and epithelial lining fluid were determined with high-performance liquid chromatography after 2 days of therapy. The pharmacokinetics was calculated and compared.RESULTS: Levotloxacin concentrations in plasma and epithelial lining fluid peak were (12.6±2.3) mg/L and (11.9±2.7) mg/L respectively in the once-daily group and(19.7±1.8) mg/L and(17.8±1.7)mg/L in the twice-daily group, showing pulmonary penetration percentage >100% in both groups. The total body exposure (AUC_24h)in the once-daily and twice-daily group was(151.2±12.8) mg·h·L^-1 and(208.6±15.1) mg·h·L^-1 respectively, each higher than the minimal inhibitory concentration for severe pneumonia. The treatment success rate in the once-daily and twice-daily group was 83%(10/12)and 92%(11/12)with no significant difference(P>0.05).CONCLUSION: For critically ill patients with severe community-acquired pneumonia and receiving mechanical ventilation, the administration of intravenous levofloxacin 500 mg once and twice daily all can reach the minimal inhibitory concentration.

Key words: Levofloxacin, Pharmacokinetics, Community-acquired pneumonia, Intensive care