therapeutic drug monitoring, vancomycin, continuous administration, Mw\Pharm software

Introduction: For a long time, the Mw\Pharm software suite (MEDI\WARE, Prague, Czech Republic / Groningen, Netherlands) has been used for PK/PD modelling in therapeutic drug monitoring (TDM). Objective:The aim of this study was to find the best model in the newer Windows version of Mw\Pharm++ 1.3.5.558 (WIN) for continuous administration of vancomycin. Methods: Twenty adult patients with mean age 66±12 years, body weight 85±16 kg, and median dose 1,625 g/24h were repeatedly examined for vancomycin. Concentrations predicted by “#vancomycin_adult_k_C2“ (WIN1), ”#vancomycin_adult_C2“ (WIN2), ”vancomycin_adult_C2“ (WIN3), “vancomycin_C1“ (WIN4) WIN models and ”vancomycine (cont.inf.) %ahz“ (DOS1) and ”vancomycin adult“ (DOS2) DOS models were compared with the measured value and with DOS1 model. Statistics: Percentage prediction error (%PE) calculated as (predicted–measured)/measured or WIN-DOS1/DOS1, RMSE, Blandt-Altman bias, Pearson’s coefficient of rank correlation (R), Student’s t-test. Statistical analysis was performed using GraphPad Prism version 5.00 for Windows. Results: %PE value varied between -7.4% and -3.2%, with the exception of WIN4, the only one-compartment model, where it was -20.8%. Best outcomes were achieved with WIN3 model. WIN1 produced the lowest %PE, RMSE and Blandt-Altman bias among the WIN models, but its correlation (Pearson’s R) was less tight (Table 1). RMSE was the same in WIN3 while %PE and Bland-Altman bias were similar, with slightly better correlation when compared to WIN1. WIN1-3 models were more similar to DOS1 as %PE was -1,4 – 1,7%, whereas %PE value between the two DOS models was 4.1 ± 13.9% (NS). DOS2 produced slightly better outcomes than DOS1. Conclusion: “vancomycin_adult_C2“ and “#vancomycin_adult_k_C2“ produced the best outcomes between WIN models. Both DOS models produced lower bias and their prediction was comparable.