There were no Brazilian studies regarding potential drug-drug interactions (DDIs) in primary health care (PHC) analysing common mental disorders (CMDs) and psychotropic medication.
Objectives: To identify DDI prevalence in that setting; to classify DDI; to verify correlations with demographics, pharmacotherapeutics, psychotropic medication and CMDs. Among 430 patients interviewed 190 had more than two medications prescribed, 58.4% had DDI. Factors associated were age and number of medications. Nine types of severe DDI composed 28% patients' prescriptions, 71.9% involving psychotropic medication. Only the number of types of drugs contributed to the regression model. Results raise important aspects regarding patient safety in PHC units in Brazil are where patients with psychological complaints have to seek for health care firstly.