Evaluation of weight-based vancomycin dosing for hospitalized hemodialysis patients

Background: Current vancomycin dosing guidelines recommend targeting trough concentrations of 15-20mg/L in complicated infections to avoid treatment failure and resistance. How to accomplish this in the intermittent hemodialysis (IHD) population has not been adequately described. A weight-based vancomycin dosing protocol for IHD patients was developed to provide standardization of vancomycin dosing for this patient population. Prior to implementation of this protocol, clinical pharmacists used their individual judgment for dosing and monitoring.Objective: Compare achievement of goal (15-20mg/L) pre-IHD vancomycin levels between a group of patients dosed prior to implementation of this weight-based vancomycin dosing protocol and a group dosed after implementation.Methods: This retrospective study evaluated hospitalized IHD patients who received vancomycin and had an appropriate pre-IHD vancomycin level. Any patients with acute kidney injury or who required continuous renal replacement therapy or peritoneal dialysis were excluded.Results: A total of 145 vancomycin courses (94 pre-protocol and 51 post-protocol) were included in this study. The post-protocol group had an increased percentage of patients who achieved a pre-IHD vancomycin level of 15-20mg/L. We also found improvement in pre-IHD vancomycin levels attained in patients weighing less than 75kg and the need for additional study in patients weighing more than 105kg.Conclusion: Simplifying and standardizing vancomycin dosing for hospitalized IHD patients based on weight resulted in 37% of patients achieving goal pre-IHD vancomycin level of 15-20mg/L with zero patients having a pre-IHD vancomycin level <10mg/L.