Prolonged use of antibiotics in mild conditions: Consequences beyond bacterial resistance

Prolonged antibiotic use in mild, often self-limiting conditions represents a significant yet underrecognized clinical concern that extends beyond antimicrobial resistance. This narrative review aimed to critically examine the physiological, immunological, metabolic, and systemic consequences of unnecessary and prolonged antibiotic exposure in low-severity infections. A comprehensive literature search was conducted in PubMed/MEDLINE and the Cochrane Library using relevant MeSH terms and keywords related to antibiotic adverse effects, dysbiosis, immune modulation, metabolic syndrome, and gut-brain axis alterations. The evidence indicates that even short courses of broad-spectrum antibiotics can induce persistent gut microbiome dysbiosis, reduce microbial diversity, and increase susceptibility to opportunistic pathogens such as Clostridioides difficile. Prolonged exposure is also associated with immune dysregulation, potentially increasing the risk of allergic and autoimmune diseases. Furthermore, systemic toxicities, including nephrotoxicity, hepatotoxicity, and cardiovascular complications, may occur even at ambulatory doses. Emerging data suggest links between repeated antibiotic use and metabolic disturbances, including weight gain and alterations in the gut-brain axis. Collectively, these findings reinforce the need for evidence-based prescribing practices and strengthened antimicrobial stewardship, particularly in primary care settings, to minimize avoidable harm to individual patient health.