Evaluation of the pharmacodynamic profile of commonly used intravenous vancomycin dosing schemes in patients on automated peritoneal dialysis.

Objectives: The intent of this study was to evaluate the appropriateness of commonly used intravenous (iv) vancomycin dosing schemes in patients on automated peritoneal dialysis (APD) using population pharmacokinetic (PK) modelling and Monte Carlo simulation.

Methods: Data from a single-dose PK study of 10 non-infected APD patients ≥18 years old were analysed. Patients received iv vancomycin (15 mg/kg) followed by three cycler-assisted APD dwells over 8 h, followed by two 8 h dwells. Serum and dialysate samples were collected over the entire 24 h. A three-compartment model was fitted to the data with BigNPAG. Monte Carlo simulation was used to determine the probability of achieving an AUC/MIC ratio of >400 in both the serum and the peritoneal cavity for a variety of iv vancomycin dosing schemes (1-2 g every 24-48 h).

Results: In the probability of target attainment (PTA) analyses, only 2 g of iv vancomycin every 24 h conferred >90% probability of achieving an AUC/MIC ratio of >400 for MIC values <2 mg/L in the serum. However, this dosing regimen resulted in average trough concentrations >20 mg/L. In the peritoneal cavity, no regimen yielded PTA ≥90% for MIC values ≥0.5 mg/L.

Conclusions: Although expert guidelines suggest iv vancomycin may be an acceptable empirical therapy for patients on APD with infection, these analyses indicate that iv vancomycin may not be effective for peritonitis but may be a viable option for non-peritoneal infections with MIC values ≤1 mg/L.