Factors influencing disposal methods of unused medicines: a systematic review

Objective: This systematic review aimed to describe how people store and dispose of unused and expired medicines, explore the extent of proper storage and disposal and examine factors influencing these behaviors. A comprehensive search of five databases, PubMed, Scopus, Springer Link, Science Direct, and EBSCO. The QualSyst assessment tool was applied to evaluate the quality of the included studies. The review encompassed 55 eligible studies from 27 countries, involving 31,246 participants. The refrigerator was the most common storage location (40% average) while discarding in household trash was the universal disposal method. Medicine storage at home ranged from 17.9% to 97%, with over 70% in high-income countries. Factors influencing proper storage included the presence of chronic illness, male gender with higher education, larger household size, and storage counseling. Improper storage was associated with poor consumer knowledge, male gender responsible for drug storage at home, households without children, and the presence of expired medicines. Lack of knowledge, inadequate information/guidance, absence of awareness campaigns, fear of legal consequences, perceived high costs, lack of take-back programs, inconvenience, lower education, and unemployment influenced improper medicine disposal. The overall prevalence of proper storage was 46% (95% CI: 28-65). The proper disposal rates were only 10% (95% CI: 6-14) for unused medicines and 7% (95% CI: 4-10) for expired medicines. Northern Africa and Western Asia had the highest rates of proper storage and proper disposal. Public education related to proper storage and disposal of medicine was recommended. The infrastructure to facilitate proper disposal of medicines was also needed to save the environment and people health.