Aim: A large number of medications are prescribed in pediatric clinics and this leads to the development of drug-drug interactions (DDI) that may complicate the course of the disease. The aim of the study was to identify the prevalence of potential drug-drug interactions, to categorize main drug classes involved in severe drug-drug interactions and to highlight clinically relevant DDIs in a pediatric population. Material and Methods: A total of 1500 prescriptions during the 12-month study period were retrospectively reviewed; 510 prescriptions that comprised two or more drugs were included in study. The presence of potential drug-drug interactions was identified by using the Lexi-Interact database and categorized according to severity: A (unknown), B (minor), C (moderate), D (major), and X (contraindicated). Results: There were 1498 drugs in 510 prescriptions; 253 of these (49.6%) included 2 drugs, 228 (44.7%) included 3-4 drugs, and 29 (5.6%) included ≥5 drugs. A total of 634 (42%) potential drug-drug interactions were idenfied. Among those, 271 (42.7%) were catego-Öz Amaç: Çocuk kliniklerinde çok sayıda ilaç reçete edilmektedir ve bu durum hastalığın seyrini kötüleştirebilecek ilaç-ilaç etkileşimlerinin oluşmasına neden olabilmektedir. Bu çalışmanın amacı, potansiyel ilaç-ilaç etkileşimlerinin yaygınlığını ve ciddi etkileşime giren başlıca ilaç gruplarını belirlemek ve çocuk yaş grubunda klinik olarak önemli ilaç-ilaç etkileşimlerini vurgulamaktır. Gereç ve Yöntemler: 12 aylık çalışma döneminde toplam 1 500 reçete geriye dönük olarak incelendi; bunlar içerisinden iki ya da daha fazla ilaç içeren 510 reçete çalışmaya alındı. Potansiyel ilaç-ilaç etkileşimlerinin varlığı, Lexi-Interact veritabanı kullanılarak belirlendi ve ciddiyetine göre sınıflandı: A (bilinmeyen), B (minor), C (orta), D (major) ve X (kontrendike). Bulgular: 510 reçetede toplam 1498 ilaç vardı; bunların 253'ü (%49,6) 2 ilaç, 228'i (%44,7) 3-4 ilaç ve 29'u (%5,6) ≥5 ilaç içermekte idi. Toplam 634 (%42) potansiyel ilaç-ilaç etkileşimi belirlendi. Bunlardan 271'i (%42,7) A, 284'ü (%44,8) B, 53'ü (%8,4) C ve 26'sı (%4,1) D grubu The known about this topic Considering the principles of rational drug use which considers the efficacy, safety, suitability and the cost of medication during treatment regimens would also prevent the occurrence of many drug-drug interactions. This is especially important for pediatric population, where the pharmacokinetic parameters of the medications are very different from adult population. There is scarce data on drug-drug interactions and pharmacokinetics profiles in pediatric population due to ethical and practical limitations. Contribution of the study The results of this study give detailed information about the abundance of potential clinically significant drug-drug interactions and their mechanisms in a Pediatric clinic. The studies performed on adult population extrapolated to the pediatric population may result in under or over prediction of the severity of drug-drug interactions. Therefore the prevalence of pot...