Drug-Drug Interactions in Hospitalized Urological Patients: A Retrospective Cohort Study

Introduction: Exposure to potential drug-drug interactions (pDDIs) can be a notable source of avoidable drug-related harm that requires adequate management to prevent medical errors. We aimed to evaluate pDDIs and associated factors in hospitalized urological patients on admission, during hospitalization, and on discharge. Methods: A retrospective cohort study was conducted at the Clinic of Urology of the University Clinical Centre Kragujevac, Serbia. To detect pDDIs, we used Lexicomp, which categorizes pDDIs as follows: X (avoid combination), D (consider therapy modification), C (monitor therapy), B (no action needed), and A (no known interaction). Multiple linear regression analysis was used to identify factors associated with the number of pDDIs. Results: More than half of the 220 included patients had at least one pDDI on admission and discharge (57.3% and 63.6%, respectively), whereas 95.0% had at least one pDDI during hospitalization. The total number and number of X, D, C, and B categories of pDDIs were the highest during hospitalization and the lowest on admission. Duration of hospitalization, arrhythmias, dementia, renal failure, cancer, surgery during hospitalization, number of prescribed drugs, and various pharmacological drug classes were risk factors for a higher number of pDDIs, while age, ischemic heart disease, hypertension, and development of infection during hospitalization were protective factors in at least one of the stages. The impact of renal colic depended on the stage and category of pDDI. Conclusion: More than half of the urological patients were exposed to at least one pDDIs at all stages. Medical professionals should regularly screen for pDDIs, particularly in patients with risk factors.