Analysis of medications returned to community pharmacies

There are many causes of medication waste, including excess supply, treatment changes, and patient nonadherence to therapy. Investigating medication returns may indicate areas for targeting interventions to reduce waste.

To identify and quantify the types and amounts of medications returned to community pharmacies and, specifically, to quantify the percentage of medication returned from the original dispensing, its therapeutic category, and reasons for not being used.

Unsolicited medication returned for disposal to the 24 community pharmacies in the Taranaki region (approximately 37,000 households) of New Zealand over a 6-week period was analyzed. The results were entered into a database, recording medication, amount originally issued (if known), date of issue, Anatomical Therapeutic Chemical (ATC) classification, and reason for nonuse. Cross-tabulation of ATC category versus percentage returned as well as ATC category versus reason for returns was performed. Adjusted standardized residuals were investigated to determine specific cells that were in excess of the expected counts.

Complete information was available for 2704 items. The majority (51%) of returns contained 75-100% of the original dispensed amount of medication. For the respiratory category, 77% of the returns were in the 75-100% group, significantly more than for any other therapeutic group. Reasons for returns were recorded as bereavement (22%), surplus to requirements (17%), expired (8%), medication change (11%), dose change (3%), and unknown (39%). The cardiovascular group and respiratory groups had a higher rate of returned drugs due to medication changes and surplus to requirements, respectively.

The majority of returned medications contained greater than 75% of the original amount issued. Identification of therapeutic groups having higher rates of returns due to medication changes or surplus to requirements may suggest areas to target to reduce medication waste.