Drug Allergies in Older Adults: A Major Problem in a Specific Population.

Introduction: The use of medications in older adults is increasing due to the prevalence of chronic diseases. Data on the characteristics of drug allergies (DAs) in older adults are limited. This study investigated the prevalence and clinical characteristics of DAs in patients aged 65 years and older.

Methods: Patient records were examined retrospectively between January 2018 and December 2022. The study included 200 patients aged ≥18 years who met the criteria for diagnosis of type B drug reactions. The patients were divided into two groups: the adult group (18-64 years) and the older adult group (≥65 years).

Results: Advanced age was an independent risk factor for the development of anaphylaxis and immediate and delayed hypersensitivity reactions (odds ratio [OR] = 4.296; 95% confidence interval [CI] = 1.700-10.855; p = 0.002, OR = 3.800; 95% CI = 1.247-11.579; p = 0.019, OR = 3.028; 95% CI = 1.248-7.343; p = 0.014, respectively). Older adults had higher rates of comorbidities and polypharmacy (p < 0.001, p = 0.016, respectively), beta-lactam antibiotic allergy (p < 0.001), and hospitalization and intensive care unit (ICU) admission for DAs (p = 0.024, p = 0.045, respectively).

Conclusion: Older age was an independent risk factor for anaphylaxis and both immediate and delayed reactions. Older adults had higher rates of comorbidities, polypharmacy, beta-lactam antibiotic triggers, and hospitalization and ICU admission.