Disposal of unnecessary and expired medicines in households: Practices and factors associated with proper medicine disposal using the extended Theory of Planned Behavior

Growing medicine use raises environmental concerns due to pharmaceutical residues, which can be mitigated through proper household disposal. Objective(s): This study investigated household practices and background factors related to the proper disposal of unnecessary and expired medicines in Finland. Using the extended Theory of Planned Behavior (TPB), the study also explored psychosocial factors influencing individuals' intention and behavior regarding proper medicine disposal. An online survey was conducted among loyalty customers of the University Pharmacy in 2023. The data were analyzed using frequencies, Chi-Square tests, and Structural Equation Modeling (SEM) based on the extended TPB. Results: The final data included 5004 respondents. Most households reported returning unnecessary (84.7%) and expired (97.6%) medicines to pharmacies or designated collection points, while 33.5% retained unnecessary medicines for potential future use. Key factors influencing disposal practices included age, education, chronic illness, and recycling habits. SEM revealed that personal norms, perceived behavioral control, situational factors, and subjective norms significantly influenced disposal intentions, while intention, situational factors, and perceived behavioral control directly affected disposal behavior. While proper medicine disposal is common in Finnish households, further improvement is needed, particularly regarding unnecessary medicines. The findings highlight the need for ongoing communication and easy-to-use and time-effective disposal solutions. Communication should be designed to engage both the rational and emotional dimensions of medicine users and appeal to moral values, such as sense of duty and responsibility. Communication should specifically target groups less engaged in proper disposal, such as younger individuals and those without chronic conditions. • Most households returned unnecessary and expired medicines properly to pharmacies. • Retaining unnecessary medicines for potential future use was also common. • Several background factors were associated with proper medicine disposal. • Personal norms and perceived behavioral control most strongly influenced intention. • Intention to properly dispose of medicines was the strongest predictor of behavior.