Medicare Part D denied a drug needing prior authorization? What the rule says and how to appeal.
Checked against the current rules on September 23, 2026.
A denial for a drug needing prior authorization 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 drug needing prior authorization under a Medicare Part D plan is governed byPrior Authorization and Other Utilization Management Requirements and§ 423.578 Exceptions process.. 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 denial explain exactly which prior-authorization requirement wasn't met?
Was the clinical information the plan asked for already sent to the plan before the denial?
Does the patient's chart already document the specific diagnosis or lab result the plan's criteria require?
What a winning appeal has to show
An appeal that wins usually includes:
The plan's own prior-authorization clinical criteria for this drug — A plan must make its coverage criteria available — comparing the actual criteria to the patient's chart is how a PA denial gets reversed. (Request this from the plan.)CMS Guidance § 40.4
Chart notes, labs, or diagnosis codes matching the plan's own stated criteria — Prior authorization is a documentation match, not a clinical judgment call — showing the record already satisfies the criteria is usually the whole appeal. (Your doctor's office provides this.)CMS Guidance § 40.4
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:
Point-by-point, how the patient's diagnosis and clinical record meet each of the plan's own stated prior-authorization criteria.CMS Guidance § 40.4
The specific diagnosis, relevant lab values, and treatment history supporting the request.42 CFR 423.578
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
- § 423.578 Exceptions process.as of September 23, 2026
- 42 CFR 423.566as of September 23, 2026
- Prior Authorization and Other Utilization Management Requirementsas of July 6, 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.
