Medicare Part D denied a temporary supply after a formulary change? What the rule says and how to appeal.
Checked against the current rules on September 23, 2026.
A denial for a temporary supply after a formulary change isn't the end of the story — Medicare Part D plans have to follow specific coverage rules, and a denial that doesn't square with those rules is exactly the kind of appeal that tends to win.
Here's what the rule actually requires, what evidence usually turns a denial around, and the deadline you're working against.
What the rule requires
Coverage for a temporary supply after a formulary change under a Medicare Part D plan is governed by§ 423.120 Access to covered Part D drugs.. A Medicare Part D plan generally cannot apply a stricter test than what these rules require.
Questions that decide it
Before you appeal, these are the facts that usually decide whether a denial like this holds up:
Did the patient enroll in this plan in the last 90 days, or switch plans mid-year?
Did the plan remove this drug from its formulary or add a new restriction to it partway through the plan year?
Was the patient already taking this exact drug before the enrollment or formulary change?
What a winning appeal has to show
An appeal that wins usually includes:
Pharmacy fill history showing the drug was already being taken — §423.120(b)(3) entitles a new enrollee or someone affected by a mid-year formulary change to a temporary transition supply — proof the drug was already in use is the whole basis for the entitlement. (You or your family provide this.)42 CFR 423.120
The enrollment date or the formulary-change notice date — The transition-fill right is time-limited around the enrollment or change event — the date establishes eligibility. (You or your family provide this.)42 CFR 423.120
Your deadline to appeal
No deadline to make this first request — it's your initial ask, not yet an appeal. The 65-day appeal clock only starts once the plan denies it.42 CFR 423.566
The plan itself then has its own clock to decide. 72 hours for a standard drug-benefit request (24 hours if expedited). For an exception request, the clock instead runs from receipt of your prescriber's supporting statement — 72 hours standard / 24 hours expedited from that point, or from the end of a 14-day wait if the plan never receives one. Payment requests: 14 calendar days (42 CFR § 423.568, § 423.570, § 423.572).
What to ask your doctor to address
If you're asking the treating physician for a supporting letter, it should speak to:
That the patient is currently stable on this drug and an abrupt switch or gap could cause harm.42 CFR 423.120
Questions people ask
- Can the plan just say it's "not medically necessary" with no further explanation?
- The denial notice has to explain the basis for the decision and tell you how to appeal. If it doesn't point to a specific rule or criteria, that's itself worth raising in your appeal — you're entitled to know what standard was applied.
- What if I don't have all the evidence listed above?
- Include what you have. An appeal with partial evidence and a clear explanation of the rule still gets a real review — it doesn't need to be complete to be worth filing.
Sources — last checked September 23, 2026
- § 423.120 Access to covered Part D drugs.as of September 23, 2026
- 42 CFR 423.566as of September 23, 2026
Related
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By CaseWhy Appeals editorial. See how this content is produced. Not legal advice. Not affiliated with or endorsed by Medicare, CMS, or any health plan. A product of CaseWhy LLC.
