Adverse drug reactions in internal medicine units and associated risk factors.

Objectives: This study was designed to assess the prevalence of adverse drug reactions (ADRs) in the internal medicine wards of two teaching hospitals, identify the most common ADRs, the principal medications involved, and determine the risk factors implicated in the occurrence of such ADRs.

Methods: All admissions over 10 weeks were followed prospectively using an intensive drug surveillance method to identify ADRs. Clinical laboratory data, the drug prescribed, and ADRs were taken into consideration.