Premix versus On-Demand Workflow Models in a Veterans Affairs Hematology/Oncology Pharmacy: Impact on Estimated Waste Costs and Patient Wait Time.

The balance between reducing patient wait time and mitigating waste of parenteral products has not been well described in literature. Evaluate the patient wait times and cost-effectiveness of employing a premix versus an on-demand workflow model for compounding parenteral admixtures in a hematology/oncology infusion setting. This single center, retrospective cost analysis compiled manually documented monthly waste reports and estimated drug pricing for the institution to calculate the cost of waste during both premix and on-demand compounding workflows. Time to administration was audited for one week with both models. Over a period of 28.5 months following the premix model, 564 products were documented as wasted ($1,196,014.01 in estimated drug purchasing cost). Over a period of 3 months following the on-demand model, 12 products were wasted ($34,823.98 in estimated drug purchasing cost). Switching models reduced the monthly average number of wasted products from 20 to 4 per month; the average cost of waste was reduced from $41,965.40 to $11,607.99 per month ( < .0001). Overall patient wait time from clearance until administration, excluding any recommended wait times after premedication administration (if applicable), was similar in both models: an average of 38.26 minutes in the premix model and 40.97 minutes in the on-demand model. Premixing parenteral admixtures was not cost effective at our institution. After resuming an on-demand compounding model, the monthly cost of waste (based on drug pricing alone) was reduced by over 70%. The wait time from clearance to treatment administration was similar in both models.