For older adults, managing medications can be a burden and could lead to medication non-adherence. To decrease risks associated with medication non-adherence, healthcare providers may recommend medication reminder apps as an assistive tool. However, these apps are often not designed with consideration of older adults' needs, capabilities, and limitations. To identify whether available apps are suitable for older adults, we conducted an in-depth cognitive walkthrough and a heuristic evaluation of the most commonly downloaded medication reminder app. Findings revealed three main issues: 1) difficulty in navigation, 2) poor visibility, and 3) a lack of transparency. We also selected the top five downloaded medication reminder apps and categorized user reviews to assess app functionality and usability problems. The results of our analysis provide guidance for app design for older adult users to provide effective tools for managing medications and supporting patient/user health.