Intravenous Vancomycin Therapeutic Drug Monitoring in Children: Evaluation of a Pharmacy-Driven Protocol and Collaborative Practice Agreement

BACKGROUND. : Vancomycin optimization is challenging, requiring careful therapeutic drug monitoring (TDM) to avoid toxicity and ensure an efficacious concentration. Most prescriptions are empiric and often discontinued within 72 hours, which makes early TDM unnecessary. Although TDM using trough levels is common, the area under the concentration-time curve (AUC) is the preferred pharmacodynamic target. We studied the effect of a pharmacy-driven vancomycin collaborative practice agreement (CPA) at a children's hospital that delayed TDM up to 72 hours and targeted a 2-point 24-hour AUC of ≥400 mg × h/L. METHODS. : We retrospectively reviewed vancomycin courses in patients aged ≥30 days who received vancomycin between April 1, 2011, and August 30, 2017. We implemented the CPA on June 1, 2014. Outcomes included CPA use, use of TDM, dosage adjustments, and development of acute kidney injury; we compared courses given while monitoring only trough levels (TO-TDM) with those given while using the CPA (AUC-TDM). We performed interrupted time series analyses to account for preintervention trends. RESULTS. : We included 2379 courses in the TO-TDM period and 2155 in the AUC-TDM period. During AUC-TDM, 87% of the courses were managed by the CPA. In adjusted interrupted time series analyses, CPA implementation was associated with an initial change in level of -0.265 (95% confidence interval [CI], -0.336 to -0.189) TDM and an initial change in level of -0.332 (95% CI, -0.506 to -0.163) dosage adjustments. The 1-year risk of acute kidney injury decreased after CPA implementation (odds ratio, 0.695 [95% CI, 0.539-0.91]). CONCLUSION. : The pharmacy-driven vancomycin CPA resulted in less monitoring and fewer dose adjustments without increasing AKI.