Post-marketing surveillance constitutes an essential component of drug regulatory affairs, providing critical safety oversight following market authorization. This comprehensive study examines pharmacovigilance systems through systematic literature review and empirical data analysis spanning 2015-2024. The research investigates surveillance methodologies, regulatory frameworks, signal detection performance, and international system comparisons. Findings reveal substantial growth in adverse event reporting from 2.4 million to 7.1 million annual reports globally, with electronic submission adoption exceeding 91%. Signal detection analysis demonstrates 65% validation success rates, with 74% of significant signals identified within two years post-marketing. Age-stratified analyses reveal elevated adverse drug reaction risks in pediatric and geriatric populations. Regulatory response times demonstrate appropriate risk-based prioritization, with life-threatening events receiving expedited attention. International comparisons identify harmonization achievements and opportunities for system enhancement. Persistent challenges include underreporting, causality assessment complexity, special population knowledge gaps, and resource constraints. The study recommends continued technological innovation, enhanced international collaboration, expanded patient engagement, and evidence-based risk communication strategies.

Post-marketing surveillance, Pharmacovigilance, Adverse drug reactions, Signal detection, Drug regulatory affairs