Old drugs, new weapons: current trends in repurposing therapies against antimicrobial resistance

Antimicrobial resistance (AMR) is a globally accelerating issue threatening the efficacy of existing treatments. Repurposing approved drugs for the development of new antimicrobial agents reduces the development cost and risk. The clinical potential of repurposed medications for AMR is essential to implement coordinated strategies that encompass scientific validation and supportive regulatory frameworks. Repurposing serves as a strong method to prolong the effectiveness of current antimicrobial classes and to fill significant voids in the global AMR pipeline. The present review summarizes current trends in repurposing strategies against AMR, utilization of non-antibiotic drugs with antibacterial activity, agents that potentiate conventional antibiotics through membrane disruption or efflux pump inhibition, and host-directed therapies that modulate immune responses and combination therapies. We also highlight advances in systems pharmacology, in silico screening, and phenotypic assays that enable rational identification of repurposing candidates. Although significant regulatory and economic barriers persist, including weak intellectual property protection, limited commercial incentives, and market constraints, swift attempts are being made to address the issues.