Adverse drug events in two emergency departments in Naples, Italy: an observational study.

The aims of this study, conducted in the emergency departments of two hospitals of Naples (Italy), which differ in type of catchment area and in the number of daily visits, were to determine: (1) the percent of emergency department visits due to adverse drug events (ADEs); (2) the percent of visits requiring hospitalisation due to acute ADEs; (3) the drugs implicated in ADEs; and (4) the types of ADEs and their frequency. We studied all emergency department visits at the A. Cardarelli and Incurabili hospitals between 8.00 a.m. and 8.00 p.m. (prospectively), and between 8.00 p.m. and 8.00 a.m.(retrospectively) for two 10-day periods. When possible, a form was completed for each subject. Patients were asked if they had taken a drug (name, dosage and reason for its use) in the previous 2 weeks. Of the 2442 emergency visits considered, 34 (1.3%) were drug related. Of the 480 patients who were subsequently hospitalised 17 (3.6%) had an ADE. The number increased to 34 (8.9%) in the 379 patients who took drugs in the 2 previous weeks. Non-steroidal anti-inflammatory drugs accounted for 26.5% of cases, antibiotics 23.6%, and antihypertensive agents 17.7%. The most frequent ADEs were gastrointestinal diseases(diarrhea, vomiting and haemorrhagic gastritis) and cutaneous rash (erythema, dermatitis). This study shows that ADEs account for a large percent of hospital admissions and confirms that drug-induced disorders is a notable public health problem.