The Influence of a Therapeutic Drug Monitoring Service on Vancomycin‐Associated Nephrotoxicity

Abstract

Vancomycin's widespread use as the mainstay antibiotic against methicillin‐resistant Staphylococcus aureus infections is complicated by its narrow therapeutic index. Therapeutic drug monitoring (TDM) using area‐under the concentration curve (AUC)‐guided dosing is recommended to optimise therapy and prevent vancomycin‐associated nephrotoxicity (VAN). In 2018, a consultative TDM Advisory Service (the Service) was piloted at an Australian hospital to enable AUC‐guided vancomycin dosing. This study sought to compare the incidence of VAN pre‐ and post‐Service implementation. A 4‐year retrospective observational study of intravenous vancomycin therapy (>48 hours) in adults (≥18 years), spanning 3‐years pre‐ and 1‐year post‐implementation of the Service was undertaken. Nephrotoxicity was defined as an increase in serum creatinine concentrations of ≥26.5 μmol/L or ≥50% from baseline, on ≥2 consecutive days. Univariate analysis was performed to compare patients pre‐ and post‐implementation, and with and without VAN. Independent factors associated with VAN were identified using a multivariate model. In total, 971 courses of vancomycin therapy, administered to 781 patients, were included; 764 courses (603 patients) pre‐implementation and 207 courses (163 patients) post‐implementation. The incidence of VAN decreased by 5% post‐Service implementation [15% pre‐implementation vs 10% post‐implementation; p = 0.075). Independent factors associated with VAN were sepsis, heart failure, solid organ transplant, concomitant piperacillin‐tazobactam, and average vancomycin AUC during therapy. In conclusion, there was a non‐significant trend towards a reduced incidence of VAN after the Service. Larger, prospective studies are needed to confirm the efficacy of the Service.This article is protected by copyright. All rights reserved