Adverse drug reactions as the cause of emergency department admission: focus on the elderly.

The use of medications could be responsible of both side effects and adverse drug reaction (ADR). Identifying risk factors could improve the possibility of avoiding severe reactions in old people. We investigated the prevalence of unpredictable drug adverse reactions among patients admitted to the emergency departments (EDs) of three large Italian hospitals in the period 2005-2008. Clinical characteristics and demographics were carefully recorded in a dedicated database. The assessment of the drug reactions was carried out by an allergist after the first emergency evaluation. Over the considered period, 56,031 patients were admitted at the ED, 2644 (21.2%) of which for ADR. Out of those patients, 55 (2.1%) were identified as unpredictable ADRs. In 96% of the cases the clinical presentation was cutaneous and antibiotics were the most frequently responsible drugs. Patients over 65 years accounted for 37% of the reactions. In those patients the multiple drug regimens were significantly more frequent, as well as the presence of comorbidities. Smoking habit, alcohol abuse and personal and familiar history of atopy did not differ between the younger and the elderly. In the older group, antibiotics were more frequently involved, whereas in the <65 years, nonsteroidal antinflammatory drugs accounted for most reactions. Our date outline that in the elderly the comorbidities and correlated multiple regime therapy cause an increased incidence of ADRs, thus suggesting a careful management of therapeutics regimens by means of educational campaigns for patients and guidelines for doctors finalized to avoid excessive drug prescription.