This study uses a participatory design to develop a user-friendly prototype of the current Danish digital platform, Shared Medication Record (SMR), to improve patient safety and minimize medication errors for patients with multimorbidity. A fundamental challenge for medication prescribing is the lack of access to an accurate medication list, which impairs effective communication between healthcare professionals and increases the risk of medication errors. We used a participatory design to identify the major problems with the existing SMR and develop a prototype for a redesigned SMR that addresses these problems. We argue that this prototype will improve communication between healthcare providers, promote patient involvement in their own care, and ultimately reduce medication errors related to the SMR. Moreover, we argue that the participatory design with its emphasis on user involvement and design iterations is a strong approach when designing IT solutions for complex problems in healthcare.