The prior authorization form: which one you need and how to fill it in

Benefily Team10 November 20269 min read

A completed prior authorization form on a desk, ready to send to a Part D plan

A prior authorization form is not one document. For a Medicare Part D drug it is usually either the plan’s own coverage determination form or the CMS model form, and sometimes a plain letter, because the rules require a plan to accept any written request. Picking the wrong one, leaving out the prescriber’s statement, or sending it to the wrong fax line can add days before the plan’s legal clock even starts. This guide explains which form applies, what to put on it, what the plan has to do once it arrives, and how to work out the deadline from the moment it is received.

Key takeaways

For a Part D drug, the plan’s own coverage determination form and the CMS Model Coverage Determination Request Form are both acceptable. A plan must accept any written request.
Exception requests usually need a prescriber’s supporting statement. Without it, the plan can ask for more information and the clock can stall.
The standard decision deadline is 72 hours from receipt of a complete request. The expedited deadline is 24 hours.
The clock runs from when the plan receives a complete request, so keep proof of the date and time it was sent.
The CMS model form cannot be used for weight-loss drugs, so a request for those usually goes through another route.

What counts as a prior authorization form

In Medicare Part D the term is used loosely. Pharmacies, prescribers and plans all say ‘prior authorization form’, but the legal mechanism underneath is a coverage determination: a decision by your plan about whether it will cover a drug, and in what circumstances. A prior authorization is one kind of coverage determination, and an exception request is another. The paperwork sits on top of that decision rather than being a separate process.

That matters because the rules attach to the decision, not the document. A plan cannot refuse a valid written request simply because it arrived on the wrong form. It can, however, ask for information it needs to decide, and that request for information is one of the most common reasons a case stalls.

“CMS has posted a model form to assist Part D enrollees in asking their Medicare drug plans for a coverage determination (including an exception request). Use of this model form is optional.”
— Centers for Medicare & Medicaid Services, prescription drug appeals forms

The three routes and when each applies

Most people end up using one of three routes. Which one applies depends on whether your plan publishes its own form and whether you are asking for coverage, an exception, or payment for a drug you have already bought.

Route	Who usually uses it	When it fits	Watch out for
The plan’s own coverage determination form	Prescribers and members, sent to the plan’s listed fax or portal	Any standard prior authorization or exception, where the plan publishes a version	Plans can ask for extra documents, and some forms say a prescriber’s statement is mandatory for exceptions
The CMS Model Coverage Determination Request Form	Members, their representatives or prescribers, sent to the plan	When the plan has no form of its own, or you want a neutral starting point	Use is optional, and the plan may still need additional documentation before it decides
A plain written letter	Anyone able to write a clear request	A fallback when no form is to hand, provided it names the drug, the plan and the reason	Missing identifiers such as the member ID and drug name slow the decision

Which written route to use for a Medicare Part D drug request

What goes on the form

Whichever route you use, the plan needs the same core facts to decide. Leaving any of them out is the commonest reason a request is returned rather than decided.

Your full name, date of birth, member ID and the plan name, exactly as they appear on your card.
The drug name and strength, and the prescriber’s name, NPI number and contact details for the plan to call back.
The diagnosis, or the medical reason the drug is needed, in the prescriber’s words.
Any drugs you have already tried, with dates and the reason each one stopped working or could not be used.
For an exception, a statement from your prescriber explaining why the covered alternatives would not be as effective or would cause harm.
Whether you are asking for a standard or an expedited decision, and the reason if expedited.

The most common reason a form stalls

The form arrives with the patient’s details filled in but no clinical reason, or with the reason written as ‘per doctor’. The plan then requests the missing detail, and the 72-hour clock does not restart from the request for information.
Ask the prescriber’s office to send the clinical reason in its own words, with the diagnosis code, on the same submission.

The deadline, worked through

Most people only find out how long the process takes once it is too late to change anything, so it helps to do the arithmetic before you send. The standard timeframe is 72 hours from the plan’s receipt of a complete request. The expedited timeframe is 24 hours from the same point. Both are counted in clock hours, not working days, so a weekend is no pause.

Take a worked example. A prescriber’s office faxes a complete coverage determination request to a plan on Monday 2 November 2026 at 09:00, and the plan’s fax log confirms receipt at that time. A standard decision is due by 09:00 on Thursday 5 November. An expedited decision, if the prescriber’s statement qualifies, is due by 09:00 on Tuesday 3 November. If the fax log shows receipt at 16:30 on the Monday instead, every deadline moves to the same time of day, so the earlier you can prove receipt, the earlier the decision is owed.

The rule also works in your favour when a plan misses it. A failure to decide within the deadline is treated as a denial, which lets the case go to the next stage of review. The guide to what to do after a denial covers that stage in detail.

Where the CMS model form cannot help

The CMS model form is written for the Part D coverage determination process, and it states plainly that it cannot be used for some drug categories. Weight-loss drugs are one of them, along with barbiturates, benzodiazepines and fertility drugs. A request for a drug used for weight loss, such as semaglutide or tirzepatide for that purpose, usually runs on the plan’s own form under a different clinical rule, which is why the Wegovy and Ozempic guides on this site treat the weight-loss exclusion as a separate question.

The model form also does not replace a prescriber’s duty to explain the clinical reason. A tidy form with no supporting reason is still a form the plan can return with questions.

After you send it

Keep the transmission confirmation with the date and time, and note who you spoke to if you call. A plan should give you its decision in writing. If it approves a drug, check the approved quantity and duration against the prescription before you collect it. If it denies the request, the denial letter should say how to ask for a redetermination, and the deadline for doing so.

Benefily does not submit forms on your behalf and does not hold a database of individual plan forms. What it does publish is the Part D formulary filing for each plan, so you can check whether a drug is flagged for prior authorization or has a quantity limit before you start the paperwork. The drug and payer pages show that flag from the filing, and the lookup on the prior authorization page covers the same ground for a single drug and plan.

Frequently asked questions

Which prior authorization form do I need for Medicare Part D?

Use your plan’s own coverage determination form if it publishes one. If it does not, the CMS Model Coverage Determination Request Form is an acceptable starting point. A plan must accept any valid written request, so a clear letter with the required details also works.

Does the prior authorization form need a doctor’s signature?

A prescriber can request a coverage determination on your behalf without being your appointed representative. For an exception request, plans typically need a prescriber’s supporting statement. If you file as your own representative, the plan may ask for a signed authorisation form.

How long after I send the form will the plan decide?

A standard request must be decided within 72 hours of the plan receiving a complete request, and an expedited request within 24 hours. The clock starts at receipt of the complete request, not when the form was first sent, so keep proof of the date and time.

Can I use the CMS form for a weight-loss drug?

No. The CMS model form states that it cannot be used for certain drug categories, including weight-loss drugs. Requests for those drugs usually go through the plan’s own form or another route the plan specifies.

Related on Benefily

Sources

Administrative information only. Benefily reports what a payer has published in its own prior-authorization policy as of the effective date shown. It is not medical advice, not a coverage or payment guarantee, and not an authorization. Requirements vary by plan, place of service and member benefits — always verify with the payer before rendering service.