Mezlocillin disposition in chronic hemodialysis patients

The pharmacokinetics of a single 1-g intravenous dose of mezlocillin were examined in six functionally anephric patients undergoing hemodialysis. Hemodialysis clearance calculated by plasma extraction ratios across the dialyzer membrane and by dialysis fluid agree well, averaging 26 and 32 ml/min. Dialyzer extraction ratios averaged 0.16 +/- 0.07, and 23.3 +/- 9.6% of the dose was measured in the dialysate. Plasma clearances (104 +/- 45 ml/min) and steady-state volumes of distribution (0.22 +/- 0.07 liter/kg) of mezlocillin showed good agreement with literature values. The nonrenal clearance (4.25 +/- 2.30 liters/h per 1.73 m2) of mezlocillin was appreciable. Drug loss by hemodialysis is small and should have little effect on therapeutic dosage needs.