In patients undergoing PD, blood level control after vancomycin (VCM) administration is difficult to achieve because of wide variation among individuals. Therefore, we evaluated the usefulness of a VCM clearance(CLVCM) prediction formula CLVCM(PET), which takes peritoneal equilibrium test (PET) results of PD patients into account, and a second prediction formula CLVCM(CG), which uses the CG formula, in 39 patients. Vd of VCM was set at 1.07 L/kg, and the VCM concentration data were fitted to a one-compartment model. The CLVCM value was defined as follows: CLVCM(PET) used creatinine clearance (CLcr) values of patients with a residual kidney[CLcr(R)] and those of patients undergoing PD[CLcr(PD)], defining the CLVCM value as 0.715 × CLcr(R) + 0.22 × CLcr(PD), and CLVCM(CG) defined the CLVCM value as being equal to the CLcr estimated based on the Cockcroft–Gault(CG) formula [CLcr(CG)] × 0.789. These values were used to calculate estimates. Prediction accuracy measures for estimates calculated with CLVCM(PET) and CLVCM(CG) were as follows: ME:1.5 and −0.2 μg/mL, MAE:3.8 and 3.5 μg/mL, and RMSE:5.2 and 4.6 μg/mL, respectively. In 88 % of blood levels calculated with CLVCM(PET) and 79 % with CLVCM(CG), the ratio of the predictive value to the measured value was within 0.67-1.5. Based on these results, the CG-based prediction formula appears to be easier to use and more useful.
