title: Pitfalls in dosing vancomycin.
abstract: BACKGROUND
  Vancomycin is a frequently used antibiotic for the treatment of methicillin-resistant gram-positive bacteria. Newer guidelines suggest dosing vancomycin to achieve a trough concentration between 15 and 20 mg/L. Achieving this higher concentration requires greater doses of the antibiotic. Even when using a nomogram, these higher doses often result in excessively elevated trough levels and increase the risk for vancomycin-associated acute kidney injury. We undertook this quality improvement project to better understand the reasons contributing to a toxic vancomycin trough level.
  
  
  METHODS
  Over a 9-month period, we examined all vancomycin trough concentrations greater than 25 mg/L to determine their cause.
  
  
  RESULTS
  Fifty-four elevated levels were identified in 38 patients. In 47 instances, adequate data were available for analysis. We could classify the etiology of the excessive levels into 4 groups: (1) incorrect timing of the blood collection, (2) improper dosing, (3) changing renal function and (4) abnormal pharmacokinetics/pharmacodynamics.
  
  
  CONCLUSIONS
  Educational programs could correct the first 3 problems. However, only more frequent therapeutic drug monitoring or use of another, less toxic, antibiotic would remedy the last one.
authors.affiliation: Department of Medicine, College of Medicine, University of Arizona, Tucson, Arizona.
authors.forename: Sireesha
authors.initials: S
authors.lastname: Koppula
authors.forename: Shivani
authors.initials: S
authors.lastname: Ruben
authors.forename: Farhan
authors.initials: F
authors.lastname: Bangash
authors.forename: Harold M
authors.initials: HM
authors.lastname: Szerlip
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008991:Monitoring, Physiologic; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000097:blood / Q000188:drug therapy; D014640:Vancomycin / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin