Abstract The objective of this study was to evaluate drug interactions based on medical records of patients hospitalized in University Hospital Lauro Wanderley (UHLW) in João Pessoa-PB, Brazil. This was a quantitative, descriptive study with a cross-sectional design. This research was conducted in the medical clinic of the above hospital by analyzing pharmaceutical intervention in medical records. The investigated samples consisted of all medical profiles with drug interaction information of patients hospitalized from June 2016 to June 2017. Most of these drug interactions were determined and classified by Micromedex® Solutions database. This research was approved by the Ethics Committee in Institutional Human Research, protocol number 2.460.206. In total, 331 drug interactions were found in 131 medical profiles. Dipyrone, enoxaparin, sertraline, ondansetron, quetiapine, tramadol, bromopride, amitriptyline, and simvastatin were medications that showed highest interactions. According to Anatomical Therapy Classification (ATC), drugs that act on the central nervous system result in more interactions. The most prevalent interaction was between dipyrone and enoxaparin. Some limitations of this study are the lack of notifications and data on drug interactions.