Background: In response to the lack of consideration of patient’s kidney function when prescribing drugs, the electronic Clinical Decision Support System (CDSS), Janusmed drugs, and renal function have been developed. This system offers knowledge on prescribing drugs to patients with impaired kidney function. Studies have shown that CDSS has the potential to lower the inappropriate prescription rate for patients with impaired kidney function. However, the general problem that CDSS faces is a low implementation rate because of inadequate usability.

Aim: The aim was to evaluate the usability of the digital interface Janusmed drugs and renal function and map ways to improve the interface.Method: Think aloud sessions and semi-structured interviews were conducted with eight medical doctors and three clinical pharmacists. Data from the think-aloud sessions were structured through an affinity diagram, also called the KJ-method, to obtain a diagram of how the interface is used and possible improvements of the system. Furthermore, Nielsen’s ten usability heuristics were used to evaluate the usability of the system.

Results: A total of six violations were found in the system, but they scored low on severity (1-2 points). The affinity diagram obtained showed the following five main themes on ways to improve the system: interface/technical functions, patient data, renal function, self-assessment, and future development.

Conclusion: Janusmed drugs and renal function is a well-designed and user-friendly CDSS.However, there is still room for further improvements in the design and functionality of the interface that would increase the usability of the system