Trends and Gender Disparities in Medical Narcotics Utilization in South Korea: A Nationwide Population‐Based Study, 2019–2023

BACKGROUND: In South Korea, a substantial volume of prescription psychotropics is dispensed outside the national health insurance reimbursement system, creating a pharmacovigilance blind spot. We investigated nationwide utilization patterns of medical narcotics to identify potential safety signals using the Narcotics Information Management System (NIMS) database. METHODS: This population-based descriptive study analyzed NIMS data covering all controlled substances dispensed in South Korea from January 2019 to May 2023. We examined overall trends and stratified patterns for anorexiants and ADHD medications. Prescription volumes were expressed as estimated dispensing units (EDU) per 1000 persons per month using resident registration population data as denominators. RESULTS: Among 3.1 million dispensing cases, anorexiants exhibited a stark gender disparity. Women at primary care clinics received approximately 440 EDUs per 1000 women per month-approximately 15 times the volume dispensed to men-concentrated among women aged 30-49, suggesting widespread prescribing outside approved indications for aesthetic weight management. ADHD medications were predominantly dispensed to males, with the largest gender gap observed in adolescents aged 10-19 and a progressively narrowing disparity in older age groups. Dispensing rates for both drug classes increased steadily over the study period, with the most pronounced rise in ADHD medications observed after the resumption of in-person schooling following COVID-19 disruptions. CONCLUSION: This study provides the first population-level analysis of medical narcotics utilization in South Korea's non-reimbursed sector. The disproportionate exposure of young women to psychotropic anorexiants constitutes a compelling pharmacovigilance signal. Addressing this requires not only an integrated data infrastructure linking NIMS with national health insurance records, but also the restoration of meaningful professional oversight over prescribing outside the reimbursement system.