Background: There is an enhanced international awareness that the improper disposal of unwanted and unused medications may have a detrimental effect on the environment.
Objectives: The aim of this study was to determine the proportion of unused medications in New Zealand that are not returned to a pharmacy for disposal and are instead disposed of via land fill or water systems. In addition, this study intended to identify why these medications were unused or unwanted.
Design: An online survey was placed on the New Zealand National Poisons Centre website for a period of three months during 2008. This consisted of a series of questions with predefined answer sets and asked about collection of medications, why there may be unused medications, storage of medications and disposal of medications.
Results: This survey was completed by 452 individuals. 62% of respondents currently had unwanted medications in their house. The most common reason for people to have leftover medication was 'medical condition improved or resolved' (n=307). Depending on formulation type, between 13-24% of unused medications were returned to pharmacies with tablets and capsules being most likely to be returned and liquids most likely to be added to water systems.
Conclusions: A significant percentage of unwanted medications are disposed of via routes that have the potential to adversely affect the environment. Reducing excess medications and wastage as well as education of appropriate disposal techniques may minimize their potential impact on the environment.