The economic impact of wasted prescription medication in an outpatient population of older adults.

The causes and costs of outpatient medication waste are not known. We report the results of a cross-sectional pilot survey of medication waste in a convenience sample of 73 New Hampshire retirement community residents aged 65 years or older. We used questionnaires and in-home pill counts to determine the annual occurrence of medication waste, defined as no intention to take leftover medicines prescribed within the past year. Mean individual annual cost of wasted medication was $30.47 (range = $0-$131.56). Waste represented 2.3% of total medication costs. The main causes for waste included: resolution of the condition for which the medication was prescribed (37.4%), patient-perceived ineffectiveness (22.6%), prescription change by the physician (15.8%), and patient-perceived adverse effects (14.4%). Individual costs were modest, but if $30 per person represents a low estimate of average annual waste, the US national cost for adults older than 65 years would top $1 billion per year.