Optimization of the vancomycin administration regimen by clinical pharmacists based on a population pharmacokinetics model: a prospective interventional study.

Abstract

In vancomycin treatment, the rates of correct blood sampling and initial trough concentrations within the target range are very low. Studies of interventions by clinical pharmacists based on population pharmacokinetics (PPK) models are limited. This study aimed to evaluate the intervention effect of clinical pharmacist-mediated optimization of the vancomycin administration regimen based on a PPK model. Retrospectively enrolled patients constituted the control group, and prospectively enrolled patients constituted the intervention group. The vancomycin administration regimen, trough concentration, pharmacokinetic parameters, and clinical outcomes of the two groups were compared. The control and intervention groups comprised 236 and 138 patients, respectively. Compared with those in the control group, the therapeutic drug monitoring (TDM) and correct TDM sampling time rates in the intervention group were significantly higher (76.92% vs. 43.59%; 63.9% vs. 39.0%, both p < 0.001). The rates of an initial trough concentration within 10-20 mg/L and an adjusted regimen were also significantly higher in the intervention group (55.80% vs. 30.51%, 71.95% vs. 39.18%, both p < 0.001). The rate of an area under the curve (AUC) within 400-650 mg·h/L was higher in the intervention group than in the control group (52.7% vs. 36.6%, p < 0.001). The eradication rates of Gram-positive bacteria were 91.4% in the intervention group and 81.3% in the control group (p = 0.049). Eight patients developed acute kidney injury (AKI) in the control group; however, no AKI occurred in the intervention group (p = 0.029). Intervention by clinical pharmacists can increase the rate of correct sampling time. Using the PPK model combined with Bayesian estimation, clinical pharmacists can greatly increase the trough concentration and AUCs within the target range, especially for adjusted regimens. Higher PK/PD target rates resulted in better Gram-positive bacterial eradication and reduced renal toxicity of vancomycin.