VANCOMYCIN REDISTRIBUTION - DOSING RECOMMENDATIONS FOLLOWING HIGH-FLUX HEMODIALYSIS

Although increased vancomycin clearance has been reported with highly permeable hemodialysis membranes (such as polysulfone), failure to consider post-dialysis redistribution could lead to unnecessary dosage supplementation. In protocol 1, twelve hemodialysis patients admitted for vascular access thrombectomy received 15 mg/kg of vancomycin as surgical prophylaxis. Post-operatively, patients under-went high-flux hemodialysis (HFHD) for two hours using a Fresenius(TM) F-80 potysulfone dialyzer (Q(B) = 417 +/- 49, Q(D) = .800 ml/min). Vancomycin's intradialytic clearance increased 13-fold compared to the patient's endogenous clearance (120 +/- 59 vs. 9 +/- 8 ml/min, respectively) yet dialysate recovery indicated that only 17% of body stores were removed (179 +/- 70 mg). Although serum vancomycin levels decreased 33% during HFHD, vancomycin levels increased in all patients following dialysis and the post-rebound values reached 87% of the pre-dialysis concentration. In protocol 2, eight outpatients receiving maintenance HFHD with a F-80 dialyzer (Kt/V = 1.29 +/- 0.08) were given 20 mg/kg of vancomycin immediately following dialysis on Monday; pre- and post-levels were measured during the next three dialysis treatments. The predialysis serum vancomycin levels were >7.5 mug/ml (9.7 +/- 1.0 mug/ml; range 8.0 to 11.0) in all patients the following Monday. Thus, vancomycin clearance is increased during HFHD, but redistribution post-HD minimizes changes in serum levels. We recommend a 20 mg/kg i.v. loading dose and subsequent doses of 15 mg/kg every seven days; to account for individual variability, weekly vancomycin levels should be drawn before dialysis.