diff --git a/src/lib/jobs/__tests__/medication-inventory-expire.test.ts b/src/lib/jobs/__tests__/medication-inventory-expire.test.ts
new file mode 100644
index 000000000..0a81312dd
--- /dev/null
+++ b/src/lib/jobs/__tests__/medication-inventory-expire.test.ts
@@ -0,0 +1,24 @@
+/**
+ * v1.4.25 W19b — module-shape contract for the
+ * medication-inventory-expire job. The actual sweep logic lives in
+ * `expireStaleInUseItems` (covered by
+ * `src/lib/medications/inventory/__tests__/service.test.ts`); this
+ * test pins the queue name + cron schedule so a typo in the worker
+ * registration is caught at the unit-test level.
+ */
+import { describe, expect, it } from "vitest";
+
+import {
+  MEDICATION_INVENTORY_EXPIRE_QUEUE,
+  MEDICATION_INVENTORY_EXPIRE_CRON,
+} from "@/lib/jobs/medication-inventory-expire";
+
+describe("medication-inventory-expire module", () => {
+  it("exports the canonical queue name", () => {
+    expect(MEDICATION_INVENTORY_EXPIRE_QUEUE).toBe("medication-inventory-expire");
+  });
+
+  it("schedules at 03:30 Europe/Berlin", () => {
+    expect(MEDICATION_INVENTORY_EXPIRE_CRON).toBe("30 3 * * *");
+  });
+});
diff --git a/src/lib/jobs/medication-inventory-expire.ts b/src/lib/jobs/medication-inventory-expire.ts
new file mode 100644
index 000000000..dfa94fbb5
--- /dev/null
+++ b/src/lib/jobs/medication-inventory-expire.ts
@@ -0,0 +1,34 @@
+/**
+ * v1.4.25 W19b — pg-boss helper for the daily
+ * `medication-inventory-expire` queue. The cron at 03:00 Europe/Berlin
+ * (interleaved with the other 03:xx cleanup crons) sweeps every user
+ * for IN_USE pens whose 30-day in-use window has lapsed and flips
+ * their state to EXPIRED.
+ *
+ * The expire pass is idempotent — re-running it within the same day
+ * only updates rows that the previous pass missed (because they hit
+ * 30 days between the two runs). EXPIRED is a terminal-ish state in
+ * the state machine; once flipped, a row stays EXPIRED until the
+ * user explicitly deletes it or marks it USED_UP.
+ *
+ * Notification surface: opt-in only. The W19b scope deliberately
+ * leaves the push notification disabled by default — Marc directive
+ * "notifications saturate the lock screen on first sync" applies
+ * here too. Users opt in via Settings → Notifications (a future
+ * preference toggle); until then the job is silent and the user
+ * sees the EXPIRED badge in the UI on next page-load.
+ */
+
+export const MEDICATION_INVENTORY_EXPIRE_QUEUE = "medication-inventory-expire";
+
+/**
+ * Cron schedule (Europe/Berlin) for the daily expire pass. 03:00
+ * matches the idempotency-cleanup slot and lands inside the existing
+ * 02:xx–03:xx maintenance window. Co-locating with the other cleanup
+ * crons keeps the late-night CPU profile coherent.
+ */
+export const MEDICATION_INVENTORY_EXPIRE_CRON = "30 3 * * *";
+
+export interface MedicationInventoryExpirePayload {
+  triggeredAt: string;
+}
diff --git a/src/lib/jobs/reminder-worker.ts b/src/lib/jobs/reminder-worker.ts
index 3652930b3..0316ab45c 100644
--- a/src/lib/jobs/reminder-worker.ts
+++ b/src/lib/jobs/reminder-worker.ts
@@ -40,6 +40,12 @@ import {
   type PrDetectionPayload,
 } from "@/lib/jobs/pr-detection";
 import { detectPersonalRecordsForUser } from "@/lib/personal-records/pr-detection-worker";
+import {
+  MEDICATION_INVENTORY_EXPIRE_QUEUE,
+  MEDICATION_INVENTORY_EXPIRE_CRON,
+  type MedicationInventoryExpirePayload,
+} from "@/lib/jobs/medication-inventory-expire";
+import { expireStaleInUseItems } from "@/lib/medications/inventory/service";
 import { rotateLegacyMoodLogSecrets } from "@/lib/moodlog-secret";
 import { deleteMessage } from "@/lib/telegram";
 import { decrypt, encrypt } from "@/lib/crypto";
@@ -1171,6 +1177,29 @@ async function handlePrDetection(
   }
 }
 
+/**
+ * v1.4.25 W19b — daily expire-stale pass for `MedicationInventoryItem`
+ * rows. Flips IN_USE pens whose 30-day window has lapsed to EXPIRED
+ * via the pure state-machine evaluator.
+ */
+async function handleMedicationInventoryExpire(
+  jobs: Job<MedicationInventoryExpirePayload>[],
+) {
+  void jobs;
+  await withBackgroundEvent("job.medication_inventory_expire", async (evt) => {
+    try {
+      const count = await expireStaleInUseItems({ nowMs: Date.now() });
+      evt.addMeta("inventory_expired_count", count);
+    } catch (err) {
+      evt.addWarning(
+        `medication-inventory-expire failed: ${
+          err instanceof Error ? err.message : String(err)
+        }`,
+      );
+    }
+  });
+}
+
 async function handleOffhostBackup(jobs: Job<OffhostBackupPayload>[]) {
   void jobs;
   await withBackgroundEvent("job.offhost_backup", async (evt) => {
@@ -1421,6 +1450,7 @@ export async function startReminderWorker() {
     HOST_METRIC_QUEUE,
     FEEDBACK_AGGREGATOR_QUEUE,
     PR_DETECTION_QUEUE,
+    MEDICATION_INVENTORY_EXPIRE_QUEUE,
   ];
 
   for (const q of allQueues) {
@@ -1453,6 +1483,11 @@ export async function startReminderWorker() {
     // every user; per-user push-suppression cannot apply on the cron
     // path (the silent flag is set by the ingest hooks).
     [PR_DETECTION_QUEUE, PR_DETECTION_FALLBACK_CRON],
+    // v1.4.25 W19b — daily expire-stale pass for the per-pen inventory
+    // entities. Flips IN_USE rows whose 30-day clock has blown to
+    // EXPIRED at 03:30 Europe/Berlin (in the existing 02:xx–03:xx
+    // maintenance window, right after idempotency-cleanup).
+    [MEDICATION_INVENTORY_EXPIRE_QUEUE, MEDICATION_INVENTORY_EXPIRE_CRON],
   ];
 
   for (const [name, cron] of schedules) {
@@ -1560,6 +1595,11 @@ export async function startReminderWorker() {
     { localConcurrency: PR_DETECTION_CONCURRENCY },
     handlePrDetection,
   );
+  await boss.work<MedicationInventoryExpirePayload>(
+    MEDICATION_INVENTORY_EXPIRE_QUEUE,
+    { localConcurrency: 1 },
+    handleMedicationInventoryExpire,
+  );
 
   return boss;
 }