Comparing Vancomycin Area Under the Curve With a Pharmacist Protocol that Incorporates Trough and Maximum Doses at a Children's Hospital.

Abstract

Updated vancomycin guidelines suggest dose adjustment based on area under the curve in a 24-hour period (AUC24). This study aims to determine whether a pharmacist managed vancomycin protocol that incorporates maximum dosing paired with trough monitoring can achieve appropriate vancomycin AUC24 exposures. A retrospective review was performed evaluating vancomycin usage from October 2018 through September 2019 at a children's hospital. Patients with less than 4 doses or lack a trough concentration were excluded. Vancomycin AUC24 were estimated using 2 calculations: 1) the Le method, incorporating age and serum creatinine, and 2) the trapezoidal method based upon population data and patient-specific trough. Target AUC24 ranges were assessed. AUC24 goals were 400 to 600 mg·hr/L, but due to known variations between calculations, a variance of 20 mg·hr/L was allowed for each end of the goal. Secondary analyses included evaluations of efficacy and toxicity. Two-hundred twenty-three patients were included. Initial doses were estimated to meet AUC24 goals in only 63%. After trough-based dose modification, 81% achieved a therapeutic AUC24. Using the trapezoidal method, therapeutic concentrations were found in 51% of patients based on the initial dose and 77% after dose modification. Only 6.3% of patients had kidney injury with only 1 of those patients having any calculated AUC24 > 600 mg·hr/L and none above 620 mg·hr/L. No clinical failures were identified. Increased initial dosing in infants and children is needed to result in AUC24 exposures recommended in the guidelines. Maximum dosing paired with trough monitoring may be an alternative to AUC24 monitoring in areas that are unable to perform AUC24 calculations. Prospective data are needed to validate these conclusions.