Abstract
BACKGROUND: Irrational drug use remains a global health challenge, particularly in underserved communities with limited healthcare access. In Thailand, despite the Rational Drug Use (RDU) initiative, problems such as antibiotic misuse and selfmedication persist. Rational Drug Use Literacy (RDUL)-the ability to access, understand, evaluate, and apply drug information-is vital for improving medication behaviors. While most efforts focus on health professionals, the role of community leaders has been less explored. METHODS: A cross-sectional study was conducted with 328 participants in Pathum Thani Province, including 168 community members and 160 community leaders selected through stratified random sampling. Data were collected using a structured questionnaire and a validated RDUL tool. Structural Equation Modeling (PLS-SEM) was used to assess direct and moderating effects of situational and socioenvironmental factors on RDUL. RESULTS: Community leaders exhibited higher Rational Drug Use Literacy (RDUL) than community members (M = 41.90 vs. 39.48, p = .003), particularly in accessing, appraising, and applying drug information. Structural Equation Modeling revealed that both situational factors (β = 0.357, p < .001) and socio-environmental factors (β = 0.168, p = .021) positively influenced RDUL, indicating that favorable circumstances and supportive environments enhance individuals' medication literacy. Importantly, leadership played a nuanced role: it diminished the influence of situational factors on RDUL (β = -0.634, p < .001) while moderately amplifying the effect of socioenvironmental factors (β = 0.327, p = .058). These results highlight that community leaders not only enhance overall medication literacy but also alter how contextual factors contribute to informed drug use. CONCLUSIONS: Community leaders play a complex but crucial role in shaping RDUL. While they strengthen certain literacy dimensions, their influence also alters contextual effects. RDUL strategies should leverage leaders as trusted figures while enhancing their capacity to promote informed medication use. Incorporating community leadership into health programs may increase the effectiveness and sustainability of RDU efforts in resource-limited settings.