Reaching the target: time and dose required to achieve target vancomycin plasma concentrations in admitted patients

In our hospital, patients are treated with continuous vancomycin infusion following standard dosing guidelines. Recent literature suggests that obese and neutropenic patients may require increased vancomycin dosages. This study aimed to reassess our dosing guidelines by evaluating how the time and dose required to achieve vancomycin target concentrations differ across specific patient groups compared to all vancomycin patients.

A retrospective cohort study was conducted using hospital records from patients treated with continuous vancomycin infusion between 1 January and 31 December 2023. Adult patients treated according to the antibiotic guidelines, with at least one vancomycin target concentration measurement, were included. We compared the time and maintenance dose required to reach target concentrations in neutropenic patients (neutrophils <1.5 × 109/L), patients weighing >100 kg, patients with augmented renal clearance (ARC; glomerular filtration rate >130 mL/min/1.73 m2) and all vancomycin patients.

The median time to reach target was 2.59 days for all vancomycin patients (n = 244), and 2.73, 2.74, and 3.39 days for ARC patients (n = 5), neutropenic patients (n = 15) and patients weighing >100 kg (n = 50), respectively. The median maintenance dose was 2000 mg/day among all vancomycin patients, compared to 3000 mg/day for patients weighing >100 kg and neutropenic patients and 4000 mg/day for ARC patients.

According to current guidelines, there is no significant difference in the time required to achieve vancomycin target concentrations between neutropenic patients, ARC patients and all vancomycin patients. However, patients weighing >100 kg took nearly a day longer to reach target concentrations (P < 0.001) and required higher maintenance doses, as did neutropenic and ARC patients.