Medication data is a crucial part of patient data. Medication data is stored in a centralized archive, and made accessible to health care professionals and citizens. Re-usability of medication data requires it to be not only interoperable, but also complete and reliable. We evaluated e-prescription data stored in a national archive. The data consists of 596 patients with 76411 e-prescriptions. The interim results show the data to be complete when stored, whereas data reliability would require more user training.