ABSTRACT
To determine the incidence, diversity of [ADRs], and impact of pharmacovigilance on reporting. This prospective and retrospective study was carried out in the Department of Medicine, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia between January to December 2011 in 600 patients of ADR. Data regarding age and gender distribution of the patients, incidence rate, drugs, body systems/organs involved in ADR, time of occurrence of adverse drug reactions, total number of drugs administered, and impact of pharmacovigilance on finding the incidence rate of ADR were recorded. Comparison of the 2 data was carried out to determine the impact of pharmacovigilance. Incidence rate of ADRs in retrospective study was 3.1% and 5.5% in the prospective study. The highest incidence of ADR [retrospective 15% and prospective 14.5%] was observed in both groups in patients receiving more than 10 drugs. The frequency of ADR in relation to age in both groups was highest in patients of age >60 years; it was 52.7% in retrospective study and 54.5% in prospective study. Antibiotics were the more frequently involved in ADR, [48.5% in prospective study and 36.9% in retrospective study]. The system most commonly involved in ADR was gastrointestinal tract 47.4% in retrospective study and 57.6% in prospective study. None of the ADR proved to be fatal. Low incidence of hospitalized ADR in our study [5.5%] is due to lack of awareness in healthcare professionals in reporting ADR. Undoubtedly, pharmacovigilance brought more patients with ADR to record