title: A method of determining the dose of digoxin for heart failure in the modern era.
abstract: BACKGROUND
  The therapeutic range for digoxin in heart failure has recently changed to become lower and narrower, and the new range is associated with improved mortality. However, dosing methods have not been modified to reflect this change. In this study, we sought to develop a new method to determine the initial dose of digoxin in patients with heart failure.
  
  
  METHODS
  Over a 6-month period, medical records were screened and reviewed for hospitalized adult patients who had a steady state digoxin concentration. A multiple linear regression was estimated relating digoxin concentration, digoxin dose, creatinine clearance, and ideal body weight to generate an equation relating the dose of digoxin with these variables and a specific target digoxin concentration of 0.7 ng/mL (0.9 nmol/L). This new method was then compared with 2 existing methods.
  
  
  RESULTS
  Included in the study were 54 patients (mean [SD] age, 68 [15] years, with a mean (SD) creatinine clearance of 50 (25) mL/min (0.8 [0.4] mL/s) and mean (SD) ideal body weight of 62 (11) kg. Our proposed method and the Jusko and Koup method were more accurate than the Jelliffe method in predicting digoxin concentration. Root mean square errors were as follows: for the Jelliffe method (using ideal body weight), 0.810; for the Koup and Jusko method (with heart failure), 0.401; our proposed method, 0.375. The proposed method was then used to create a dosing nomogram.
  
  
  CONCLUSIONS
  Because the new therapeutic window of digoxin is associated with improved outcomes, more intensive dosage refinement should be considered. To this end, we offer new dosing recommendations and a nomogram for determining the initial dose of digoxin in patients with heart failure.
authors.affiliation: Department of Pharmacy Practice, University of Illinois at Chicago, Chicago, IL 60612, USA. jbauman@uic.edu
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Bauman
authors.forename: Robert J
authors.initials: RJ
authors.lastname: DiDomenico
authors.forename: Marlos
authors.initials: M
authors.lastname: Viana
authors.forename: Melissa
authors.initials: M
authors.lastname: Fitch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D004077:Digoxin / Q000008:administration & dosage*; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049451:Nomograms
chemical_list: D002316:Cardiotonic Agents; D004077:Digoxin