[Consideration on Expiration Days Setting for the Introduction of Drug Vial Optimization].

When drug vial optimization(DVO)is implemented, the medical facilities will be forced to bear the cost of the divided- use drugs not used up within the expiration date. We determined the expiration days to use up the residual drugs in the vial within the expiration period. The cost of discarded drugs was calculated from the prescription data of anticancer drugs. We estimated the discarded drug volumes when the expiration period was 0, 1, 2, 7, 8, 14, or 28 days for each liquid anticancer drug. When the expiration period was 7 days, the discarded amount was equivalent to 5.5% of the amount on 0-day expiration period. Only one drug with a 28 day expiration period had to be discarded. When the expiration period is 1 to 2 days, drugs are always discarded and the medical facilities must bear the cost of the wasted drugs. If the expiration period is 7 days or more, most of the medicine will not be discarded. To introduce DVO to medical facilities without economic loss, extending the expiration period of DVO must be considered.