Vancomycin Pharmacokinetic Parameters in Patients with Hemorrhagic Stroke

Abstract

Background: Infections are a common medical complication in hemorrhagic stroke patients, with vancomycin commonly used as empiric therapy. The purpose of this study was to evaluate the pharmacokinetic parameters of vancomycin in hemorrhagic stroke patients. Methods: This was a retrospective study of adult patients with aneurysmal subarachnoid hemorrhage (aSAH) or intracerebral hemorrhage (ICH) admitted between May 2010 and February 2015 who received vancomycin. Predicted pharmacokinetic parameters based on population data were compared with calculated pharmacokinetic parameters based on serum trough concentrations. Results: Eighty aSAH patients and 66 ICH patients met inclusion criteria. In the aSAH group, the mean dosing regimen was 17.6 ± 4 mg/kg every 12 (8–12) h. The mean measured trough concentration was lower than the predicted trough concentration (9.9 ± 4.1 vs. 19 ± 8.7 μg/mL; p < 0.001). The mean calculated elimination rate constant was higher than the predicted value (0.135 ± 0.04 vs. 0.092 ± 0.03 h−1; p < 0.001), and the mean calculated half-life was lower than predicted (5.7 ± 1.8 vs. 8.3 ± 2.9 h; p < 0.001). In the ICH group, the mean dosing regimen was 15.9 ± 4.3 mg/kg every 12 (8–12) h. Similarly, the mean measured trough concentration was lower than the predicted trough concentration (10.7 ± 4.6 vs. 17.5 ± 8.5 μg/mL; p < 0.001). The mean calculated elimination rate constant was higher than the predicted value (0.106 ± 0.03 vs. 0.079 ± 0.02 h−1; p < 0.001), and the mean calculated half-life was lower than predicted (7.2 ± 2.3 vs. 9.6 ± 3.2 h; p < 0.001). Conclusions: Patients with hemorrhagic stroke exhibited pharmacokinetic alterations favoring increased elimination of vancomycin when compared to predicted pharmacokinetic parameters based on population data. This may result in underexposure to vancomycin, leading to treatment failure and other medical complications.