Vancomycin is a glycopeptide antibiotic, used for parenteral treatment of severe Gram-positive bacterial infections. It is on the list of reserve antimicrobials. Due to the narrow therapeutic window, regular therapeutic drug monitoring of vancomycin and maintaining its serum concentrations within the therapeutic range is required. Too high concentrations are problematic because of the nephrotoxicity; on the other hand, too low concentrations can lead to development of bacterial resistance and ineffective therapy.
In the retrospective study, we analysed parenteral vancomycin treatment at Department of Infectious Diseases, University Medical Centre Ljubljana in 2018 and 2019. Adults from non-intensive care unit and from intensive care unit were included. We evaluated the adequacy of vancomycin initial dosing and therapeutic drug monitoring according to the clinic´s internal recommendations. We also checked the development of acute kidney failure during the vancomycin therapy and the impact of potential risk factors on its occurrence.
The research included 148 patients (average age 65.8 years, 52 % men) with a total of 176 vancomycin therapies. Sepsis and bacterial pneumonia were the main indications for vancomycin treatment. Treatment was most often started with the standard dosing regimen of 1000 mg/12 h. In 67.9 % of therapies, initial dose of vancomycin was adjusted according to patient´s renal function. Loading dose was used in 17.3 % of therapies, mostly 2000 mg dose and more often at intensive care unit. Therapeutic vancomycin concentrations were monitored in 158 therapies, the first concentration was mostly measured before steady state was reached. All measurements reached the therapeutic concentration range of vancomycin (10–15 μmol/L) in less than 20 % of therapies. Measured trough concentrations higher than 15 μmol/L prevailed among inappropriate trough concentrations. Acute kidney failure developed in 14.0 % of the therapies. Among potential risk factors, only the presence of at least one therapeutic serum concentration of vancomycin above the therapeutic range was significantly associated with its occurrence.
According to these results, we have suggested some possible improvements in systemic vancomycin treatment at Department of Infectious Diseases.