title: A comparison of automated dispensing cabinet optimization methods.
abstract: OBJECTIVE
  Results of a study comparing two methods of optimizing automated dispensing cabinets (ADCs) are reported.
  
  
  METHODS
  Eight nonprofiled ADCs were optimized over six months. Optimization of each cabinet involved three steps: (1) removal of medications that had not been dispensed for at least 180 days, (2) movement of ADC stock to better suit end-user needs and available space, and (3) adjustment of par levels (desired on-hand inventory levels). The par levels of four ADCs (the Day Supply group) were adjusted according to average daily usage; the par levels of the other four ADCs (the Formula group) were adjusted using a standard inventory formula. The primary outcome was the vend:fill ratio, while secondary outcomes included total inventory, inventory cost, quantity of expired medications, and ADC stockout percentage.
  
  
  RESULTS
  The total number of medications stocked in the eight machines was reduced from 1,273 in a designated two-month preoptimization period to 1,182 in a designated two-month postoptimization period, yielding a carrying cost savings of $44,981. The mean vend:fill ratios before and after optimization were 4.43 and 4.46, respectively. The vend:fill ratio for ADCs in the Formula group increased from 4.33 before optimization to 5.2 after optimization; in the Day Supply group, the ratio declined (from 4.52 to 3.90). The postoptimization interaction difference between the Formula and Day Supply groups was found to be significant (p = 0.0477).
  
  
  CONCLUSIONS
  ADC optimization via a standard inventory formula had a positive impact on inventory costs, refills, vend:fill ratios, and stockout percentages.
authors.affiliation: Department of Pharmacy, West Virginia University Hospitals, Morgantown, WV. oneild@wvuhealthcare.com.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: O'Neil
authors.affiliation: Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, NC.
authors.forename: Adam
authors.initials: A
authors.lastname: Miller
authors.affiliation: Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, NC.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cronin
authors.affiliation: Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, NC.
authors.forename: Chad J
authors.initials: CJ
authors.lastname: Hatfield
mesh_terms: D000046:Academic Medical Centers / Q000379:methods* / Q000592:standards; D004356:Drug Storage / Q000379:methods* / Q000592:standards; D006801:Humans; D008508:Medication Errors / Q000517:prevention & control; D008510:Medication Systems, Hospital / Q000592:standards; D010607:Pharmacy Service, Hospital / Q000379:methods* / Q000592:standards