PHARMACOKINETICS OF VANCOMYCIN WHEN ADMINISTERED DURING HIGH-FLUX HEMODIALYSIS

This study was undertaken to evaluate the pharmacokinetics of relative ly high-dose vancomycin when administered during high flux hemodialysi s using a polysulfone membrane (F-80, Fresenius). Five noninfected, an uric patients received a single dose of 25 mg/kg of vancomycin infused during hemodialysis at a rate of one gram per hour and timed such tha t the end of the infusion coincided with the end of dialysis. Blood sa mples were drawn during the infusion, up to six hours after the end of dialysis and then prior to the next three dialysis treatments. Spent dialysate was collected during the infusion. Samples were analyzed usi ng the EMIT assay. The percent of vancomycin lost during the first dia lysis session ranged from 39.1 to 55.1% (mean, 45.7 +/- 6.4). The conc entration of vancomycin at 6 hours after hemodialysis ranged from 18.2 to 45.1 mg/l (mean, 29.6 +/- 10.0 mg/l). Dialysis clearance ranged fr om 96.1 to 158.1 ml/min (mean, 130.7 +/- 30.0 ml/min). One week after dosing, serum concentrations ranged from 8.14 mg/l to 10.1 mg/l (mean, 9.0 +/- 1.0 mg/l). This study suggests than an initial dose of 25 mg/ kg of vancomycin, given during high flux dialysis, may provide adequat e serum concentrations in anuric hemodialysis patients for up to seven days. This dosing scheme reduces inconvenience to the patient and sta ff, and potentially can reduce nursing costs associated with post-dial ysis administration; its cost is minimal. At this point, subsequent do sing is best determined by therapeutic drug monitoring.