Designing and building a medication tracker for kidney patients — because nothing on the App Store came close

My wife is a kidney transplant recipient. Her daily medication schedule involves immunosuppressants that must be taken at precise times, at precise doses, and tracked against lab results — eGFR, creatinine, tacrolimus trough levels — that shift the clinical picture every few weeks. I'm managing hormone therapy myself, which adds its own set of weekly and bi-weekly schedules.

Every medication app I tried made the same assumptions: daily doses, single user, maybe a reminder. None of them handled weekly, bi-weekly, or monthly intervals without workarounds. None of them connected medication logs to lab results. And almost all of them required a cloud account — which, for sensitive health data, felt like a trust trade I wasn't willing to make.

So I built Dose Diary on weekends. The design decisions came directly from lived experience, not from user personas.

Most medication apps are designed for the general population: once-daily pills, simple reminders, maybe a refill alert. They're fine for the majority of users. But kidney transplant recipients, dialysis patients, and people on complex hormone therapy protocols exist at a different level of complexity — multiple drugs with different intervals, vitals that need logging before and after dialysis sessions, lab panels that need to be compared across months, not days.

The existing solutions forced these users to either use an app that was too simple to be useful, or a clinical system that was too complex and cold to be sustainable in daily life. There was no middle ground: an app with consumer-quality UX built specifically for the clinical depth these patients needed.

The core medication system supports scheduling at any interval from daily to monthly. Each medication has its own timing rules, meal-time relationships, and stock tracking. Reminders are tied to meal times rather than arbitrary clock times — which matters clinically, because most immunosuppressants are taken at consistent meal-relative intervals rather than strict hours.

Kidney Mode is a dedicated layer built for dialysis patients, transplant recipients, and anyone managing CKD. It extends the base medication system with clinical workflows that no general medication app attempts. The design challenge was making these features feel like a natural part of the same app — not a bolt-on clinical tool that broke the experience.

The HRT Reference Library sits alongside Kidney Mode as a separate informational layer: medically-cited guidance on hormone therapies drawn from WPATH, UCSF, and Endocrine Society sources. It's not a feature for tracking — it's a place for patients to access reliable clinical information without leaving the app or opening a browser.

Building an app where you are also the primary user changes every decision. There's no ambiguity about whether a feature is needed — you know, because you've felt the absence of it. And there's no tolerance for friction in the daily logging flow, because you experience that friction every morning.

What surprised me was how much the privacy constraint simplified the architecture. Removing cloud sync eliminated an entire class of problems: sync conflicts, latency, authentication flows, data breach liability. The SwiftData model is clean and fast. The app launches instantly. There's no onboarding because there's nothing to sign in to.

The other thing I learned: designing for edge cases first produces better general design. Every interaction pattern I designed for a fatigued dialysis patient — large targets, minimal steps, immediate confirmation — made the app better for everyone. The clinical context was a forcing function for the kind of design rigour that consumer apps often skip.