[Looking back on 20 years of work at the Porto Pharmacovigilance Centre, Portugal]

Since 1963, the World Health Organization has acknowledged pharmacovigilance as a priority area in global public health, guaranteeing permanent monitoring of drug safety. This study aimed to characterize the reports of adverse drug reactions received by the Porto Pharmacovigilance Centre (UFPorto), Portugal, in the unit's two decades of work. The analysis included all reports of suspected adverse drug reactions received from January 2001 to December 2019. We calculated the annual reporting rates and distribution by origin, type of notifier and place of work, severity, prior knowledge, and causality of the reported adverse drug reactions. During the study period, UFPorto received 9,711 notifications of suspected adverse drug reactions. Hospital institutions reported the most suspected adverse drug reactions (n = 6,003; 64%), as did physicians among healthcare workers (n = 5,284; 54.4%). The most frequently reported adverse events were severe (n = 6,275; 72%) and are described in the respective Summary of Product Characteristics (n = 6,978; 72%). Most of the reports received by UFPorto were evaluated as having "probable" causality (n = 7,473; 77%), independently of the type of notifier. The results are consistent with other data previously reported in the international medical literature and official national reports. However, the underreporting rates are still higher than expected. In approximately 20 years, UFPorto has experienced an increase in its activity in various areas of drug safety.