Cefazolin dialytic clearance by high-efficiency and high-flux hemodialyzers

Cefazolin dialytic clearance has not been determined in patients undergoing hemodialysis with high-efficiency or high-flux dialyzers. The objective of this study is to determine the pharmacokinetics and dialytic clearance of cefazolin and develop dosing strategies in these patients. Twenty-five unin fected subjects undergoing chronic thrice-weekly hemodialysis were administ ered a single dose of intravenous cefazolin (15 mg/kg) after their standard hemodialysis session. Fifteen subjects underwent hemodialysis with high-ef ficiency hemodialyzers, and 10 subjects underwent hemodialysis with high-fl ux hemodialyzers. Blood and urine samples were collected serially over the interdialytic period, during the next intradialytic period, and immediately after the next hemodialysis session. Serum and urine concentrations of cef azolin were determined by high-performance liquid chromatography. Different ial equations describing a two-compartment model were fit to the cefazolin serum concentration-time data over the study period, and pharmacokinetic pa rameters were determined. Mean dialytic clearance values for cefazolin were significantly greater in the high-flux group compared with the high-effici ency group (30.9 +/- 6.52 versus 18.0 +/- 6.26 mL/min, respectively; P < 0. 05). Cefazolin reduction ratios were significantly greater (0.62 +/- 0.08 v ersus 0.50 +/- 0.07; P < 0.005) in the high-flux group compared with the hi gh-efficiency group and correlated well with equilibrated urea reduction. T he pharmacokinetic model developed from patient data was used to simulate c efazolin serum concentration data for high-efficiency and high-flux dialyze rs. Cefazolin doses of 15 or 20 mg/kg after each hemodialysis session maint ained adequate serum concentrations throughout a 2- or 3-day interdialytic period regardless of hemodialyzer type. (C) 2001 by the National Kidney Fou ndation, Inc.