Vancomycin removal and pharmacokinetics during accelerated venovenous hemofiltration

Vancomycin pharmacokinetics are affected by renal replacement therapy and physiologic changes in critically ill patients. Literature regarding vancomycin removal and pharmacokinetics during accelerated venovenous hemofiltration (AVVH), a form of prolonged intermittent renal replacement therapy, is limited.

To describe the removal and pharmacokinetics of vancomycin during AVVH.

Eighteen critically ill adults receiving vancomycin and AVVH were included. Vancomycin serum concentrations were obtained within 4 h before and 2-6 h after the AVVH session. Patients' serum concentrations were plotted against time, and individual pharmacokinetic parameters were determined by a one-compartmental analysis. Continuous data are reported as a median (interquartile range [IQR]) and categorical data as a percentage.

The median AVVH effluent rate was 39.3 mL/kg/h (IQR 35.5-48 mL/kg/h) for a duration of 9 h (IQR 8-9.75 h). AVVH decreased vancomycin concentrations by 29.8% (IQR 24.9%-35.9%), at a rate of 3.4% per hour (IQR 3.1%-4.3% per hour) of AVVH. The vancomycin elimination rate constant and half-life were 0.039 h^-1 (IQR 0.036-0.053 h^-1 ) and 17.6 h (IQR 13.1-18.8 h), respectively. The area under the curve during AVVH was 171.7 mg*h/L (IQR 149.1-190 mg*h/L). The volume of distribution in 10 patients was 1 L/kg (IQR 0.73-1.1 L/kg). After AVVH, vancomycin 1000 mg (IQR 750-1000 mg) was needed to maintain a serum trough concentration ≥15 mg/L.

Vancomycin is significantly removed by AVVH, which requires supplemental dosing after completion of the AVVH session to maintain desired serum concentrations. Therapeutic drug monitoring of vancomycin serum concentrations is recommended for patients undergoing AVVH.