Opioid Use Disorder in Brazil: Emerging Patterns, Critical Gaps, and Implications for Public Health Policy - A Systematic Review

BACKGROUND: Opioid Use Disorder (OUD) has become a major global public health concern, yet its epidemiological and clinical profile in Brazil remains insufficiently characterized. This systematic review aimed to synthesize the available evidence on OUD in the Brazilian context. METHODS: Following a protocol registered in PROSPERO (CRD420250656485), we searched PubMed, BVS/LILACS, Scopus, and Web of Science from inception to April 30, 2025. Studies conducted in Brazil and involving individuals with OUD were eligible. Methodological quality was assessed using standardized critical appraisal tools. RESULTS: Twelve studies met inclusion criteria, with 58% rated as high methodological quality. Most studies reported low absolute numbers of opioid users. Illicit opioid use was rare (