Adverse drug reactions in older adults: a narrative review of the literature

Key summary points Aim To summarize the classification and occurrence of ADRs and identify risk factors and strategies to reduce and prevent ADRs in older adults. Findings In frail, multimorbid older adults, who are often treated with polypharmacy, ADRs are frequently associated with health burden and hospitalization. Multiple age-related risk factors, including changes in pharmacokinetics, multimorbidity, polypharmacy, and frailty can increase the risk of ADRs, and different strategies have been suggested to prevent the onset of ADRs. Message A multidimensional and holistic approach combining pharmaceutical interventions with a global evaluation of health needs and priorities can reduce the burden of ADRs in older adults. Purpose Adverse drug reactions (ADRs) represent a common and potentially preventable cause of unplanned hospitalization, increasing morbidity, mortality, and healthcare costs. We aimed to review the classification and occurrence of ADRs in the older population, discuss the role of age as a risk factor, and identify interventions to prevent ADRs. Methods We performed a narrative scoping review of the literature to assess classification, occurrence, factors affecting ADRs, and possible strategies to identify and prevent ADRs. Results Adverse drug reactions (ADRs) are often classified as Type A and Type B reactions, based on dose and effect of the drugs and fatality of the reaction. More recently, other approaches have been proposed (i.e. Dose, Time and Susceptibility (DoTS) and EIDOS classifications). The frequency of ADRs varies depending on definitions, characteristics of the studied population, and settings. Their occurrence is often ascribed to commonly used drugs, including anticoagulants, antiplatelet agents, digoxin, insulin, and non-steroidal anti-inflammatory drugs. Age-related factors—changes in pharmacokinetics, multimorbidity, polypharmacy, and frailty—have been related to ADRs. Different approaches (i.e. medication review, software identifying potentially inappropriate prescription and drug interactions) have been suggested to prevent ADRs and proven to improve the quality of prescribing. However, consistent evidence on their effectiveness is still lacking. Few studies suggest that a comprehensive geriatric assessment, aimed at identifying individual risk factors, patients’ needs, treatment priorities, and strategies for therapy optimization, is key for reducing ADRs. Conclusions Adverse drug reactions (ADRs) are a relevant he