Medicare Denied Drug Coverage (Part D Formulary)

What This Means

Your Medicare Part D plan is refusing to cover this drug either because it is not on the plan’s formulary — the plan’s own list of covered drugs — or because a formulary restriction (prior authorization, step therapy, or a quantity limit) has not been met. The fix for both runs through a formulary exception: your prescriber sends the plan a supporting statement explaining why the covered alternatives would be less effective for you or would cause adverse effects, and the plan must decide within 72 hours of receiving that statement — 24 hours if your prescriber tells the plan that waiting could put your health at serious risk (CMS exception rules). Do one thing now: call your prescriber’s office and ask them to submit an exception request with that supporting statement — the plan’s decision clock does not start until it arrives.

Turned away at the pharmacy counter instead? That rejection is not a formal denial yet — there is nothing to appeal until the plan issues one. The pharmacist should hand you a printed notice titled “Medicare Drug Coverage and Your Rights” (CMS-10147) explaining how to ask your plan for a coverage determination — the plan’s written, appealable decision, due on the same 72-hour (standard) or 24-hour (expedited) clock. You, your prescriber, or your representative can request it by phone or in writing.

Not sure this is your situation? Broad searches often land here when a neighboring guide is the better fit:

• Was the denial for Wegovy or Zepbound prescribed for weight loss? No exception can override that statutory exclusion — but the temporary Medicare GLP-1 Bridge program covers both at a $50 copay through December 31, 2027.
• Were you charged more than $35 for insulin, or anything at all for a recommended adult vaccine? That is a billing error, not a coverage decision — see insulin and vaccine price caps.
• Is the drug covered, but cheaper with cash or a discount card than through your plan? See when Part D costs more than cash.

The sections below walk through each denial reason, whether an appeal is worth it, and the exception and appeal steps in order.

Why This Happens

• The drug isn’t on your plan’s formulary. Every Part D plan has a formulary — a list of drugs it covers. Your plan may cover an alternative medication but not the specific one prescribed.
• Your plan requires prior authorization. Some drugs need advance approval from your plan before they’re covered. If your doctor prescribed the drug without obtaining prior authorization, the claim will be denied.
• Step therapy requirements weren’t met. Your plan may require you to try a less expensive drug first before it will cover the prescribed medication. If you haven’t tried the required alternative, the claim may be denied.
• Quantity limits apply. Your plan may cover the drug but limit the quantity you can receive in a given time period. If the prescription exceeds that limit, the excess may be denied.
• The drug is excluded from Part D by law. Some drug categories — like those for fertility or cosmetic purposes — are excluded from Part D coverage by federal law. Weight loss drugs were also historically excluded, but the Medicare GLP-1 Bridge program — a CMS demonstration running from July 1, 2026 through December 31, 2027 — covers Wegovy and Zepbound for eligible beneficiaries at a $50 copay (CMS). If you were denied a GLP-1 for weight loss, check whether you qualify for the Bridge.

Should You Appeal?

What To Do Next

1. Check if your drug has cost protections. Before filing an exception, make sure you aren’t being incorrectly charged:
   • Insulin is capped at $35 for a month’s supply under every Part D plan (Inflation Reduction Act, since January 2023) — see insulin and vaccine price caps.
   • Adult vaccines recommended by the CDC’s advisory committee (ACIP) are covered at $0 cost-sharing under Part D.
   • Your out-of-pocket costs for covered Part D drugs are capped at $2,100 for 2026; once you reach the cap, you pay nothing for covered drugs for the rest of the year (CMS Part D redesign instructions). Still being charged? See what to do after hitting the cap.
   • If costs are piling up mid-year, ask your plan about the Medicare Prescription Payment Plan — you can spread annual costs into monthly installments.
2. Find out exactly why the drug was denied. Call your Part D plan (the number is on the back of your plan card) and ask for the specific reason, and ask for the decision in writing — the written denial is the coverage determination you can appeal. This tells you whether you need a formulary exception, prior authorization, or something else.
3. Ask your doctor about a formulary exception. If the drug isn’t on the formulary, your doctor can submit an exception request with a statement explaining why the covered alternatives aren’t appropriate for you.
4. Request a tiering exception if cost is the issue. If the drug is on the formulary but at a high cost-sharing tier, your doctor can ask the plan to cover it at the lower tier’s cost.
5. Ask about an expedited decision if you need the drug urgently. If waiting could seriously harm your health, your doctor can request an expedited coverage determination, which must be decided within 24 hours.
6. If the exception is denied, file a formal appeal. You have 65 days from the date on the denial notice to request a redetermination from your plan, and the plan must answer within 7 days (standard) or 72 hours (expedited) (CMS redetermination rules). If your plan upholds the denial, you must file with the Independent Review Entity (IRE) within 60 days of receiving that decision — in Part D this step is not automatic (42 CFR 423.600). Your plan forwards the case for you only if it missed its own decision deadline.
7. Ask about a transition fill. If you are new to the plan — or your plan dropped or restricted your drug at the start of the plan year — and you were already taking the medication, ask the pharmacy for a one-time, 30-day transition fill so your treatment isn’t interrupted while the exception or appeal is processed.

Sources

• CMS: Part D Coverage Determinations — what counts as a coverage determination; the 72-hour/24-hour decision deadlines
• CMS: Part D Exceptions — formulary and tiering exceptions; the prescriber supporting statement; the clock starts when the plan receives the statement
• CMS: Redetermination by the Part D Plan Sponsor — the 65-day filing deadline and 7-day/72-hour decision deadlines
• Medicare.gov: Appeals in a Medicare Drug Plan — the appeal levels, including the 60-day deadline for IRE review
• Medicare.gov: Drug Plan Coverage Rules — prior authorization, step therapy, quantity limits, and the one-time 30-day transition fill
• CMS: Medicare GLP-1 Bridge — program dates (July 1, 2026 – December 31, 2027) and the $50 copay
• CMS: Final CY 2026 Part D Redesign Program Instructions — the $2,100 out-of-pocket cap for 2026
• CMS: Part D Plan Sponsor Notices — the standardized pharmacy notice (CMS-10147) and written denial notice (CMS-10146)
• 42 CFR 423.568 — standard coverage determinations: 72 hours for a benefit or exceptions request (the exceptions clock runs from receipt of the prescriber’s supporting statement), 14 calendar days for a request for payment, and 14 calendar days as the backstop when no supporting statement arrives
• 42 CFR 423.572 — expedited coverage determinations: 24 hours, likewise measured from the supporting statement

Frequently Asked Questions