Pharmacokinetic variability of vancomycin in patients with nosocomial meningitis

High doses of vancomycin are required early in the treatment of nosocomial meningitis. However, the dosage is often reduced later during treatment, irrespective of renal function. This study was designed to investigate the pharmacokinetic variability of vancomycin and the associated factors throughout the treatment course for patients with nosocomial bacterial meningitis.

This study included 17 patients who received vancomycin for nosocomial bacterial meningitis at the Tokyo Women's Medical University Yachiyo Medical Center from April 2013 to May 2020. All patients had their serum vancomycin concentrations and cerebrospinal fluid (CSF) parameters measured within 7 days of initiating treatment (early period) and after 8 days (later period) of treatment.

The relative error between the predicted serum vancomycin concentration and the measured value was significantly higher in the later period than in the early period. In 13 patients who did not have their dosing interval shortened, the vancomycin dosage/serum vancomycin concentration/estimated glomerular filtration rate (D/C/eGFR) ratio significantly decreased in the later period. Moreover, the rate of change in the D/C/eGFR ratio significantly correlated with that in the CSF protein and C-reactive protein levels.

This study suggests that the clinical condition and inflammatory response of a patient with meningitis influence the pharmacokinetics of vancomycin. Therefore, the vancomycin dosage for the treatment of nosocomial bacterial meningitis must be adjusted according to changes in the clinical condition and renal function of the patient, necessitating careful therapeutic drug monitoring.