While medications can improve the health of patients, the prescription process is complex and prone to errors. The structured medical order entry systems (CPOE) with clinical decision support (CDS) are increasingly implemented to improve patient safety, however the organizations that decide to implement them will have several challenges: understanding which classes of CDS can admit their systems, ensure that clinical knowledge is adequate and design tools for proper monitoring. We share our experience of over ten years of development and implementation of clinical decision support tools during drugs prescription process and tools that have allowed us to monitor them correctly.