Knowledge, attitudes, and practices regarding the disposal of unused and expired medicines among students at Mulungushi University

Improper disposal of unused and expired medicines is an important public health and environmental concern because it may contribute to environmental contamination, accidental poisoning, medicine misuse, and antimicrobial resistance. University students are an important population because they may accumulate unused medicines and potentially influence medicine-use and disposal behaviours within their households and communities. This study assessed knowledge, attitudes, and practices regarding the disposal of unused and expired medicines among students at Mulungushi University, Zambia. A cross-sectional study was conducted among undergraduate students at Mulungushi University between November 2025 and April 2026 using a structured, self-administered questionnaire. Of the 384 questionnaires received, seven were excluded because they were incomplete, resulting in a final analytical sample of 377 participants. Participants were selected using stratified sampling from health-related and non-health-related programmes. Data were analysed using Stata version 15. Descriptive statistics and logistic regression analyses were performed to assess knowledge, attitudes, disposal practices, and associated factors. Adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were reported, with statistical significance set at p < 0.05. Among the 377 participants included in the analysis, 232 (61.5%) were aged 18–24 years and 195 (51.7%) were male. Most participants (361; 95.8%) recognized that improper disposal of unused and expired medicines could negatively affect environmental and human health, whereas only 106 (28.1%) were aware of medicine take-back systems. Unsafe disposal practices were common: 154 (40.8%) participants reported disposing of expired medicines in household garbage and 97 (25.7%) reported flushing them into toilets or sinks. Only 7 (1.9%) returned expired medicines to pharmacies, while 11 (2.9%) returned unused medicines. Analgesics (210; 55.7%) and antibiotics (141; 37.4%) were the most commonly reported unused medicines. In the adjusted analysis, students enrolled in non-health-related programmes had lower odds of adequate knowledge than those in health-related programmes (AOR = 0.38, 95% CI: 0.23–0.62; p < 0.001) and lower odds of a favourable attitude toward safe medicine disposal (AOR = 0.40, 95% CI: 0.23–0.68; p < 0.001). Participants aged 31–35 years had higher odds of appropriate disposal practices than those aged 18–24 years (AOR = 3.68, 95% CI: 1.16–11.66; p = 0.027), whereas students in fifth year and above had lower odds of appropriate disposal practices than first-year students (AOR = 0.31, 95% CI: 0.10–0.96; p = 0.041). Despite high awareness of the potential environmental and public health risks associated with inappropriate medicine disposal, unsafe disposal practices were common among students, demonstrating a gap between awareness and actual behaviour. Differences in knowledge and attitudes by field of study suggest that educational exposure may influence medicine-disposal awareness, although causal relationships cannot be established from this cross-sectional study. The findings support targeted medicine-disposal education and the development of accessible medicine-return mechanisms within university settings. Multicentre studies are needed to determine the applicability of these findings to students in other universities and the wider population.