Adverse drug reactions associated with commonly prescribed medications: mechanisms, risk factors, clinical manifestations and management strategies

Adverse drug reactions (ADRs) are unintended and harmful responses to medicines used at normally recommended doses. They range from mild, self-limiting symptoms to severe events involving organ failure, disability or death. Although modern medicines provide substantial benefits, their safety depends on appropriate selection, prescribing, dispensing, administration, monitoring and patient participation. This narrative review summarises the principal mechanisms of ADRs, common classification systems, patient- and treatment-related risk factors, clinical manifestations associated with widely prescribed medication groups, and practical strategies for assessment, management and prevention. Predictable reactions commonly result from the known pharmacological action of a medicine or excessive exposure, whereas unpredictable reactions may involve immune hypersensitivity, reactive metabolites, mitochondrial injury or other idiosyncratic processes. Risk increases with polypharmacy, multimorbidity, older age, impaired renal or hepatic function, pregnancy, genetic variation, previous drug reactions and fragmented medication records. Clinical assessment requires a complete medication history, a plausible time relationship, evaluation of alternative causes, appropriate laboratory or imaging investigations, and structured causality assessment. Management prioritises stabilisation, withdrawal or dose adjustment of the suspected agent when clinically appropriate, treatment of the affected organ system, documentation and reporting. Prevention relies on medication reconciliation, individualised prescribing, targeted monitoring, patient education, interprofessional communication and pharmacovigilance. ADRs cannot be eliminated completely, but coordinated safety practices can reduce avoidable harm and improve the benefit-risk balance of commonly prescribed medicines.