Background Continuous vancomycin infusion (CVI) is frequently used to achieve therapeutic levels (15–25 mg/L) in patients in whom, related to their physiological characteristics (young, obese or critical patient), intermittent infusion (II) would need higher doses than those recommended (>4 g/day). Latest guidelines suggest a target of 15–20 mg/L but there is controversy over vancomycin associated nephrotoxicity in CVI.

Purpose To determine the frequency of nephrotoxicity associated with CVI and to identify risk factors.

Material and methods A retrospective cohort study was performed in a 400 bed tertiary university hospital from January 2013 to August 2016. Patients included adults treated with CVI. Dose recommended to achieve steady state concentration (Css) was 15–20 µg/mL. Data collected: demographics, body mass index (BMI), type of infection, treatment duration, vancomycin Css and AUC, dose recommended, initial and final renal function (SCr) and glomerular filtration rate (GFR) using CKD-EPI, nephrotoxicity defined by RIFLE criteria (risk, injury, failure, loss and end stage renal disease), nephrotoxic drugs and others causes of nephrotoxicity. Pharmacokinetic analysis: Bayesian estimation compartmental model (PKS System Abbott). Data are shown as median (Q1–Q3). Statistical analysis: SPSS Statistics Base 22.0.

Results 38 patients were included: 25 (65.8%) men, 55 (43–64) years, 78 (70–89) kg, BMI 26 (24–32) kg/m², critically ill 7 (18.4%). Type of infection: bone 22 (57.9%), diabetic foot 4 (10.5%), bacteraemia 4 (10.5%), CNS 4 (10.5%), abdominal 2 (5.3%) and others 2 (5.3%). Treatment duration: 9 (6–13) days. Css: 23.4 (19.6–28.1) µg/mL. AUC: 506 (435–575) µg×h/mL. Recommended dose: 3.2 (2.8–3.5) g/day. Renal function: Scr initial 0.53 (0.41–0.73) mg/dL, final 0.58 (0.47–0.78) mg/dL. GFR initial 113 (102–129) mL/min, final 107 (98–121) mL/min. Nephrotoxicity: 1 (3.8%). RIFLE 1-0-0-0-0. Risk factor: leg amputation. Nephrotoxicity was reversible. Adverse effects: phlebitis 1 (3.8%) with dropout due to adverse effect.

Conclusion CVI allows therapeutic levels (15–20 mg/L) to be to achieved, especially in bone infections. Despite an increased steady state concentration, nephrotoxicity was negligible with therapeutic drug monitoring. Phlebitis can make it difficult to administrate CVI.

References and/or acknowledgements Rybak M, Lomaestro B, Rotschafer JC, et al. Therapeutic monitoring of vancomycin in adult patients: a consensus review of the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society of Infectious Diseases Pharmacists. Am J Health Syst Pharm2009;66:82–98.

No conflict of interest