Drug Repurposing: Accelerating New Therapeutic Discoveries From Old Molecules (1990–2025)

Drug repurposing, or finding new uses for existing drugs, offers a faster, less costly alternative to traditional drug discovery by utilizing known safety profiles. This approach has evolved from chance discoveries, like minoxidil's transition from an antihypertensive to a hair-growth treatment, to a systematic, data-driven process using bioinformatics and AI. Advances in genomics and big-data analytics have made repurposing more predictive. The COVID-19 pandemic highlighted its potential, as existing drugs were rapidly tested for new applications. The review discusses the historical development, key milestones, computational strategies, and future regulatory considerations of drug repurposing.