A drug is defined as a substance capable of influencing biological functions through chemical reactions, either by agonism or antagonism, to achieve the desired therapeutic effect. During this process, several pharmacokinetic and pharmacodynamic events occur, which can be potential sites for drug interactions to occur. For patients undergoing hospital treatment, drugs of different classes are usually prescribed, and it is necessary to understand the risk of interactions between these drugs and their possible change in therapeutic efficacy or safety. Therefore, the study sought to identify the main classes of drugs, and their combinations, used in the treatment of pneumonia in pediatric patients at a teaching hospital in Brazil. This is a cross-sectional, retrospective and descriptive study, from September 2017 to December 2020, based on data obtained from medical records provided by the Júlio Bandeira University Hospital. Regarding the most used antibiotics in the analyzed period, we have: ampicillin (61.76%) and azithromycin (23.53%) in 2017; ampicillin (41.04%) and ceftriaxone (23.51%) in 2018; ampicillin (45.70%) and ceftriaxone (25.50%) in 2019; ceftriaxone (39.20%) and azithromycin (31.49%) in 2020. The main combinations identified in the study were: dipyrone and fenoterol (60.70%), dipyrone and hydrocortisone (47.92%), dipyrone and ondansetron (34.66%) and dipyrone, hydrocortisone and fenoterol (37.38%). It is important to highlight that 58 different drugs were found in the prescriptions of this period, alerting to the possibility of drug interactions of various types. In view of this, it is possible to highlight the combination of azithromycin and ondansetron as a potentially moderate risk of drug interaction, since both increase the QT interval, requiring patient monitoring by means of ECG. Therefore, an in-depth analysis of these data may be useful to prepare technical material and assist in therapeutic decision-making, improving the quality of prescriptions and the patient's clinical response, adopting an even more effective conduct, with adequate care and as close to the patient as possible. expected in relation to the pharmacological characteristics of drugs.