A Novel Vancomycin Standardized Calculations Method Achieved Therapeutic Trough Goals in Obese and Non-obese Patients in a Veterans Affairs Health Care System

Abstract

Abstract Background Pharmacokinetic dosing of vancomycin in obese patients has not been standardized. Limited literature is available on appropriate dosing of vancomycin in this increasing population. We evaluated the utilization and impact of a standardized calculation method (SCM) in obtaining therapeutic vancomycin levels. Methods A SCM, including the use of an adjusted body weight for dosing and volume of distribution in obese patients, was implemented at our institution April 2014. Retrospective medical records review of hospitalized patients with a vancomycin steady-state trough level pre- (February 2013 to March 2014) and post-implementation (June 2014 to July 2015) of the SCM. Patients with dialysis, paraplegia/quadriplegia, vancomycin level drawn < 48 hours of admit, trough level drawn > 2 hours prior to next dose, during or after vancomycin infusion were excluded. Appropriateness of vancomycin levels were evaluated between the pre- (PreG) and post-groups (PostG), as well as BMI classification. Nephrotoxicity was defined as a rise in serum creatinine > 0.5 mg/dl or > 50% from baseline during or up to 72 hours after stopping vancomycin therapy. Appropriate statistical tests were analyzed using SPSS-PC (ver. 24, Chicago, IL). Results There were no significant differences in the PreG (n = 97) and PostG (n = 97) for age, gender, length of vancomycin therapy, and non-obese and obese patients. In the PostG, significant improvement in the overall use of the SCM (P < 0.001) was determined. Other significant (P < 0.001) factors associated with vancomycin patient management in the PostG were found. There was an overall significant improvement in achieving a therapeutic trough goal of 10–20 (±1 mcg/ml) in BMI classes, predominantly in BMI Class 4 PreG 26% and PostG 74%, P < 0.05. More patients in the PreG (11) had the first trough >21 mcg/ml than the PostG, (4), P = 0.104. Patients who developed nephrotoxicity included PreG 15% and 0% PostG, P = 0.115. Conclusion SCM of vancomycin regimens resulted in a significant improvement in obtaining therapeutic trough levels overall, including the obese BMI class 4. Defined nephrotoxicity was absent in the PostG group. Disclosures All authors: No reported disclosures.