Peritoneal Clearance and Optimum Dosage Regimen of Levofloxacin in Patients under Continuous Ambulatory Peritoneal Dialysis

Introduction: We investigated the clinical significance of the peritoneal clearance of levofloxacin, which is used to treat exit-site infections caused by Pseudomonas aeruginosa in patients under continuous ambulatory peritoneal dialysis (CAPD), and proposed an optimum dose and dosage interval for treating these patients.Methods: We measured the concentrations of levofloxacin in the plasma, the drainage from peritoneal dialysis and the plasma ultrafiltrate by HPLC in 6 patients receiving CAPD, and determined the plasma unbound fraction (fuB). We also estimated the total clearance (CLtot/F), distribution volume (Vd/F) and peritoneal clearance (CLpd) in each patient.Results: The mean (S. D.) CLtot/F, Vd/F, CLpd, and fuB were 22.6 (7.34) ml/min, 76.3 (21.9) L, 3.42 (0.831) ml/min, and 69.7 (13.76) %, respectively. We examined the possible factors affecting the peritoneal clearance of levofloxacin, but did not find any definite trends.Discussion: The average CLpd was about 17% of the CLtot, but in some patients it was above 20%. It seems that the peritoneal clearance values should not be ignored in clinical practice. The minimum plasma concentration of levofloxacin in the steady state in patients under CAPD given 100mg of levofloxacin every 24h was 2.7±0.72μg/ml, which exceeded the MIC50 of the drug for P. aeruginosa. Administration of the drug at a dose of 100 mg every 48 h, a common clinical practice, may not be adequate to maintain a blood concentration high enough to attain an appropriate antibacterial effect.