title: Individualized vancomycin dosing in obese patients: a two-sample measurement approach improves target attainment.
abstract: OBJECTIVE
  To compare the likelihood of vancomycin target trough concentration attainment based on infectious diagnosis and/or minimum inhibitory concentration for the organism by using a two-sample approach versus the prior institutional standard of a trough-only approach in obese patients receiving vancomycin.
  
  
  METHODS
  Preintervention and postintervention study.
  
  
  METHODS
  Community acute care hospital.
  
  
  METHODS
  One hundred fifty hospitalized adults with a body mass index (BMI) of 30 kg/m(2) or greater and treated with vancomycin for at least 48 hours between July 2013 and March 2014 were evaluated to compare the frequency of steady-state therapeutic trough concentration attainment between two approaches: a trough-only dosing method (preintervention group [75 patients]) and a dosing strategy measuring two vancomycin serum concentrations during the elimination phase (peak and trough) to calculate pharmacokinetic parameters and individualize the maintenance regimen (postintervention group [75 patients]). Data for the preintervention group were retrospectively retrieved from a 4-month period for patients admitted between July and October 2013, prior to implementation of the two-point vancomycin dosing protocol. Initial vancomycin empiric dose selection for both groups utilized the same population-based pharmacokinetic equations.
  
  
  RESULTS
  Median (5th-95th percentile) age, weight, and BMI were 59 (34-80) years, 105 (79.8-164) kg, and 34.5 (30.0-55.1) kg/m(2) , respectively, for all patients. The percentages of initial therapeutic trough concentrations achieved in the preintervention and postintervention groups were 32.0% and 42.7%, respectively (p=0.117). For patients with a second trough measurement, 31.0% in the preintervention group and 65.2% in the postintervention group were within the therapeutic range (p=0.024).
  
  
  CONCLUSIONS
  Measurement of two serum vancomycin concentrations significantly improves subsequent target trough concentration attainment in the obese population.
authors.affiliation: Morton Plant Hospital, BayCare Health System, Clearwater, Florida.
authors.forename: Joseph
authors.initials: J
authors.lastname: Hong
authors.affiliation: Morton Plant Hospital, BayCare Health System, Clearwater, Florida.
authors.forename: Lynne C
authors.initials: LC
authors.lastname: Krop
authors.affiliation: University of South Florida Family Medicine Residency, Clearwater, Florida.|Dr. Joseph A. Eaddy Family Medicine Research Center, Clearwater, Florida.
authors.forename: Tracy
authors.initials: T
authors.lastname: Johns
authors.affiliation: Albany College of Pharmacy and Health Sciences, Albany, New York.
authors.forename: Manjunath P
authors.initials: MP
authors.lastname: Pai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D001424:Bacterial Infections / Q000150:complications / Q000188:drug therapy*; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D057285:Precision Medicine; D013203:Staphylococcal Infections / Q000150:complications / Q000188:drug therapy; D014640:Vancomycin / Q000037:antagonists & inhibitors* / Q000493:pharmacokinetics
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin
keywords: clinical pharmacy services; dosing strategies; obese; obesity; therapeutic drug monitoring; vancomycin; weight