Incidence, preventability, and causality of adverse drug reactions at a university hospital emergency department

Purpose To investigate the characteristics of ADRs in patients admitting at the emergency room of a tertiary hospital. Methods We collected the patient records of 1600 emergency room visits of a university hospital in 2018. The patient files were studied retrospectively and all possible ADRs were identified and registered. Patient characteristics, drugs associated with ADRs, causality, severity, preventability, and the role of pharmacogenetics were assessed. Results There were 125 cases with ADRs, resulting in a 7.8% overall incidence among emergency visits. The incidence was greatest in visits among elderly patients, reaching 14% (men) to 19% (women) in the 80-89 years age group. The most common causative drugs were warfarin, acetylsalicylic acid (ASA), apixaban, and docetaxel, and the most common ADRs were bleedings and neutropenia and/or severe infections. Only two of the cases might have been prevented by pharmacogenetic testing, as advised in Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines. Conclusion The same ATC classes, antithrombotics and cytostatics, were involved in ADRs causing university clinic hospitalizations as those identified previously in drug-related hospital fatalities. It seems difficult to prevent these events totally, as the treatments are vitally important and their risk-benefit-relationships have been considered thoroughly, and as pharmacogenetic testing could have been useful in only few cases.