Background When drugs are multidose packaged, all units must be dispensed to the same patient. Sometimes, patients don’t finish their treatment and return units left to the Pharmacy Department. Units returned must be discarded, so it is a loss to the Pharmacy Department.

Purpose To evaluate how much the Pharmacy Department loses when multidose packaged drugs for viral diseases are returned to the outpatient area.

Materials and Methods A single-centre retrospective observational study was carried out in the outpatient area of the Pharmacy Service of the Hospital Clínico Universtiario de Valladolid over 10 months, between June 2011 and March 2012. The following information was collected in structured tables: name of medicine, number of units returned, price to book value per unit and total value.

Results 7,764 units of drugs for viral diseases were returned during the study period. Of these units, 90% were recovered by the Pharmacy Department to be dispensed to other patients. However, 10% cannot be reused due to multidose packaging.

The return of drugs that can be reused is a gain in economic resources of 84.6% over the total value of returned drugs (€36.371).

Furthermore, the average cost per unit of reused drugs is €4.4 vs. 7.3€ for non-reused. The combos are usually multidose packaged, when it is in these drugs where unitary repackaging would be more efficient.

Conclusions 10% of the units of drugs for viral diseases returned to the outpatient area must be discarded due to multidose packaging.

Unitary repackaging allows the Pharmacy Department to recover 84.6% of the cost of returned drugs in this area.

Combos, as well as being more expensive than other drugs, are mostly multidose packaged, preventing reuse.

No conflict of interest.