Assessing the Impact and Feasibility of Pharmacist Vancomycin Dosing and Monitoring Interventions: A Pilot Program

Abstract

BACKGROUND: The benefits of pharmacist-directed vancomycin therapeutic drug monitoring (TDM) on clinical efficacy, patient safety, and hospital cost-savings are well-described in the literature. However, there is limited data surrounding the feasibility of implementing such a program. OBJECTIVES: To evaluate the outcome of pharmacist-directed vancomycin TDM compared to standard practice and describe the feasibility of its implementation within a large community health system. METHODS: This was a dual-centre, pre-post study. A vancomycin TDM tool was developed based on current guidelines and used by pharmacists to intervene within the first 24 hours of vancomycin initiation. The primary outcomes included rate of trough target attainment, attainment of area under the curve (AUC) to minimum inhibitory concentration (MIC) ratio (AUC/MIC) targets, and the incidence of nephrotoxicity. Feasibility was assessed by measuring pharmacist intervention rates using a TDM documentation tool and identifying barriers to implementation. RESULTS: Eighty-five patient records were retrospectively reviewed during the pre-intervention period. Forty patients were enrolled during the prospective post-intervention period. Trough target attainment in the pre- and post-interventions groups were 24.7% and 32.5%, respectively (p=0.361). AUC/MIC target attainment was 76.5% in the pre-intervention group, compared to 88.9% in the post-intervention group (p=0.628). Two patients experienced nephrotoxicity; both were in the post-intervention group (p=0.095). Pharmacists intervened for 72.7% of eligible patients. The most common reasons for lack of pharmacist intervention during the post-intervention period included anticipating discontinuation of therapy within 24 hours and initiation of therapy during non-clinical hours. CONCLUSION: There was a high rate of pharmacist participation in the post-intervention period. In addition, although underpowered, there was a trend towards improved serum trough and AUC/MIC target attainment. The degree of pharmacist influence on vancomycin management during the pre-intervention period is unknown, which limits evaluation of the true impact of this intervention.