How long does prior authorization take?

Benefily Team17 July 20268 min read

A pharmacist reviewing a prescription on a laptop at the pharmacy counter while a prior authorization request is processed

A standard Medicare Part D prior authorization request must be decided within 72 hours of your prescriber submitting it, and an expedited request within 24 hours — but the clock Medicare tracks and the wait you actually feel at the pharmacy counter are not the same thing. This guide sets out the exact deadlines under 42 CFR 423.568 and 423.572, what starts and stops that clock, and what current data says about how long the process really takes once you count the paperwork delays, missing forms and misrouted faxes that happen before a plan's official 72 hours even begins. It also walks through a realistic timeline and explains what happens the moment a plan misses its own deadline.

Key takeaways

Standard Medicare Part D coverage determinations: 72 hours from receipt of a complete request. Expedited: 24 hours.
The clock starts when the plan receives the full request from your prescriber, not when a pharmacy first flags the need for it or someone phones to ask.
Real-world data suggests the practical wait is often longer: prescriptions needing prior authorization take a median of four days longer to fill than ones that don't.
Missing the deadline counts as an automatic denial, and the plan must forward the case to an independent reviewer within 24 hours without you having to ask.
Incomplete clinical paperwork, requests sent to the wrong fax or department, and delays before the formal submission is even made are the most common causes of extra waiting.
Almost 3 in 10 patients who filled a prescription in the past year say prior authorization delayed them, rising to over a third among people taking several medicines.

The official deadline vs the wait you actually feel

There are really two clocks running, and mixing them up is where most confusion about timing comes from. The first is the regulatory clock: the 72 or 24 hours a Part D plan has to decide once it has received your prescriber's complete request. The second is what you might call the patient clock: the time from when you first stood at the pharmacy counter and were told the drug needed approval, to the day you actually walked out with it. The regulatory clock is short and legally enforced. The patient clock includes everything that happens before that legal clock even starts, which is often the biggest part of the delay.

Both figures are real, and both are worth knowing. The 72-hour and 24-hour deadlines tell you what a plan owes you once the paperwork lands on its desk. The longer, messier patient-clock figure tells you what to actually expect, and why a plan hitting its legal deadline perfectly can still mean a week-long wait for you.

Standard vs expedited: what Medicare actually requires

Medicare's rules for Part D drug plans are set out in 42 CFR 423.568 (standard requests) and 423.572 (expedited requests). Both start the clock the same way: on receipt of the request, not when your prescriber first decides to write it, and not when a pharmacist mentions that prior authorization will be needed.

Request type	Decision deadline	What starts the clock	What happens if the plan misses it
Standard coverage determination	72 hours	The plan's receipt of the complete request from your prescriber	Counts as an automatic denial; the plan must forward the case to the independent review entity
Expedited coverage determination	24 hours	Receipt of the complete request, where your prescriber states (or the plan agrees) that waiting could seriously harm your health or ability to function	Same automatic-denial rule, forwarded to the independent reviewer within 24 hours of the deadline passing
Exceptions request (e.g. asking for a non-formulary drug, or an exception to a restriction)	72 hours	Receipt of the prescriber's supporting statement explaining medical necessity	Same automatic denial and forwarding rule applies

Medicare Part D coverage determination deadlines (42 CFR 423.568 and 423.572).

Note what an expedited request actually requires: it isn't enough to feel like things are urgent. A prescriber has to say, in the request, that waiting for the standard timeframe could seriously jeopardise your health, and the plan has to agree (or a doctor can back that judgement on your behalf). Without that, even a request that feels time-sensitive to you defaults to the slower 72-hour track.

What the newest data says about real turnaround times

“Prescriptions requiring prior authorization took a median of four days longer to fill than those without prior authorization requirements.”
— Surescripts, analysis of new prescriptions sent in January 2026

Four days is a median, meaning half of affected prescriptions took even longer. It sits comfortably above the 72-hour legal window, which is the point: the regulatory clock only measures the part of the process a plan is directly accountable for. Everything upstream of that, getting the request written, gathered and actually submitted, isn't counted against any deadline at all. The same analysis found that nearly 3 in 10 patients who filled a prescription in the past year experienced a delay because of prior authorization, a figure that climbs to roughly 36% among people taking two or more medicines daily, and 13% said the delay made their health measurably worse.

None of that means plans are routinely breaking the rules. It means the rules only ever governed one segment of a longer chain, and the other segments (a busy prescriber's office, a fax that goes to the wrong queue, a plan asking for more clinical detail) are where most of the real-world waiting happens.

Why it often takes longer than the official deadline

What actually stretches the timeline

The clock hasn't started yet. A phone call from the pharmacy flagging that prior authorization is needed doesn't start anything; only the plan's receipt of the prescriber's formal, complete request does, and that submission can lag days behind the original prescription.
Incomplete clinical documentation. If chart notes, prior treatment history, or a required field are missing, the plan can pause to ask for more information, and that back-and-forth sits outside the 72-hour or 24-hour count.
Requests sent to the wrong place. Many practices still submit by fax, and a request sent to a plan's general enquiries line rather than its dedicated prior authorization unit can sit unprocessed for days without ever being logged as officially received.
A slow first step at the prescriber's office. The pharmacy typically flags the rejection the same day, but turning that into an actual submission depends on how quickly a busy practice files it, and how closely its fax or portal queue is monitored.
Treating an urgent case as routine. If a prescriber doesn't explicitly request expedited handling and explain why a delay would be harmful, the plan will process it on the standard 72-hour track by default, even where the situation feels time-sensitive to the patient.

A realistic example timeline

This is an illustrative walkthrough, not a real patient, but it reflects a pattern that turns up often. Say a prescriber writes a new prescription for a biologic drug that carries a prior authorization flag on the plan's formulary.

Monday, morning: the prescription is sent to the pharmacy. The pharmacist's system rejects it at the point of sale with a prior authorization flag, and the pharmacy notifies the prescriber's office by fax the same afternoon. The patient's own clock has started; the regulatory clock has not.
Tuesday: the prescriber's office is busy and doesn't process the fax until the next day. This is the single most common source of delay, and it happens entirely before the plan is legally on the hook for anything.
Wednesday: the prescriber's office submits the complete request, including diagnosis and prior treatment history. The plan's 72-hour statutory clock now formally starts.
Thursday: the plan reviews the file and finds a required lab result is missing. It contacts the prescriber's office for the missing detail rather than making a decision on an incomplete record.
Friday, afternoon: the prescriber's office supplies the missing result. The plan issues its coverage determination and approves the drug the same day.
The patient collects the drug the following Monday, seven days after the original prescription was written. The plan's own decision, once it had everything it needed, took under 48 hours, comfortably inside the 72-hour deadline. The other five days happened before the clock the deadline actually measures ever started.

That is roughly the shape of the four-day gap the Surescripts data describes: a plan that meets its legal obligation to the letter, sitting inside a process that still takes most of a week from the patient's point of view.

What happens once a plan misses its deadline

If a Part D plan does let the 72-hour or 24-hour window lapse, the rule is unambiguous: the failure itself counts as an adverse coverage determination, meaning a denial, whether or not the plan ever says no in writing. The plan then has to forward the case to the independent review entity (IRE), a reviewer outside the plan, within 24 hours of the deadline passing. You don't need to file anything to trigger that step; it's the plan's obligation, not yours.

It's worth knowing that a denial, deemed or explicit, is rarely the final word. Across Medicare Advantage more broadly, insurers made nearly 53 million prior authorization determinations in 2024 and denied around 7.7% of them, yet 80.7% of the denials that were actually appealed were partially or fully overturned. Those figures cover prior authorization across Medicare Advantage generally, not Part D drug requests alone, but the pattern they point to (denials that don't hold up once someone pushes back) is exactly why a missed deadline or a refusal is worth challenging rather than accepting.

Frequently asked questions

How long does prior authorization take for Medicare Part D?

A standard request must be decided within 72 hours of the plan receiving your prescriber's complete submission. An expedited request, used when waiting could seriously harm your health, must be decided within 24 hours. Both deadlines run from receipt of the request, not from when you first learned it was needed.

How long does an expedited prior authorization take?

24 hours from the plan's receipt of the complete request. To qualify as expedited, your prescriber has to explicitly say that waiting for the standard 72-hour timeframe could seriously jeopardise your health or ability to function, or the plan has to agree that it applies.

Why is my prior authorization taking longer than 72 hours?

The 72-hour clock only starts once the plan has received a complete request. If your prescriber's office hasn't yet submitted it, if the plan is waiting on missing clinical documentation, or if the request was sent to the wrong fax number or department, none of that counts against the deadline, even though it feels like part of the wait to you.

What happens if a Medicare Part D plan misses its own deadline?

A missed deadline automatically counts as a denial. The plan must then forward your case to an independent review entity outside the plan within 24 hours, without you needing to file anything yourself to make that happen.

Is the wait the same for every type of prior authorization request?

The core deadlines (72 hours standard, 24 hours expedited) apply to standard coverage determinations and exceptions requests alike, with the clock for an exceptions request starting when the plan receives the prescriber's supporting statement rather than the initial request itself.

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.