diff --git a/prisma/migrations/0039_medication_schedule_days_of_week/migration.sql b/prisma/migrations/0039_medication_schedule_days_of_week/migration.sql
new file mode 100644
index 000000000..ba95ae6dc
--- /dev/null
+++ b/prisma/migrations/0039_medication_schedule_days_of_week/migration.sql
@@ -0,0 +1,17 @@
+-- v1.4.23 H5 — schema drift fix for medication_schedules.days_of_week.
+--
+-- Up to v1.4.22 the column was declared in `schema.prisma` but never
+-- migrated. Code paths in src/components/medications/*,
+-- src/app/api/medications/*, src/app/api/admin/notifications/reminder-check/*
+-- and src/app/api/gamification/achievements/route.ts all reference the
+-- field. Pre-v1.4.23 deploys silently relied on Prisma's selecting
+-- a non-existent column being tolerated by Postgres for SELECT * style
+-- queries — but `prisma.medicationSchedule.create({ data: { daysOfWeek }})`
+-- would fail loudly the moment a user supplied a non-default
+-- recurrence string.
+--
+-- Add the column nullable + default NULL so existing rows mean "daily"
+-- (matches the in-code semantics: `parseScheduleRecurrence(null)`
+-- returns the all-7-days set).
+ALTER TABLE "medication_schedules"
+ADD COLUMN IF NOT EXISTS "days_of_week" TEXT;