Introduction: Drug interactions (DDIs) represent an important clinical problem particularly in elderly patients due to polytherapy, comorbidity and physiological change in pharmacodynamic and pharmacokinetic pathways. In this study we investigated the association between drugs prescribed during hospital or clinical room discharge and the development of DDIs with drugs daily used from each patient.
Methods: we performed an observational, retrospective, multicenter study on medical records of outpatients referred to general practitioners. Drug interactions (DDIs) were measured using the drug interactions probability scale. Collected data were analyzed using the Statistical Package for the Social Sciences. Results: During the study we evaluated 1,622 medical records. We recorded the development of DDIs in 10.3% of patients, of those 11.6% induced the hospitalization. Logistic regression showed an association between DDIs and sex and number of drugs used (P = 0.023). Conclusion: this real-life study shows that DDIs are common in elderly patients and physicians must take more attention after hospital discharge revaluating the treatment in order to reduce the risk of DDIs and hospitalization.