Prior Authorization for Prescription Drugs

Prior authorization is one of the most common barriers patients encounter when filling a new prescription. If your pharmacist tells you that your drug requires prior authorization — often abbreviated PA — it means your insurer will not cover the cost until it reviews and approves the prescription. Understanding who submits the request, what the process involves, how long decisions take, and what to do if coverage is denied gives you a clearer path through the system.

Why insurers require prior authorization

Health insurers use prior authorization as a cost-management and clinical appropriateness tool. The stated rationale is ensuring that high-cost or potentially misused drugs are prescribed for the right patients in the right clinical contexts. In practice, PA requirements apply most often to:

• Brand-name drugs when generic or lower-cost alternatives exist
• Specialty medications and biologics
• Drugs with significant misuse or safety concerns
• Drugs for which the plan requires a clinical justification (e.g., a documented diagnosis or treatment failure on an alternative)
• Medications with high cost-sharing that the plan restricts to patients meeting specific criteria

Not all drugs on your plan’s formulary require PA. Your plan’s formulary listing will show which drugs require PA and which are subject to step therapy or quantity limits.

Who initiates the prior authorization

The PA request is almost always initiated by your prescribing provider, not by you directly. When your pharmacy submits your prescription to your insurer, the insurer may return a response indicating that PA is required. The pharmacy informs you, and you then contact your prescriber’s office to alert them.

Your prescriber’s office will:

1. Contact the insurer (typically through a phone line, online portal, or fax dedicated to PA requests)
2. Submit the required clinical documentation — usually your diagnosis code, the clinical reason the specific drug is needed, and documentation that any required prior therapy was tried or is contraindicated
3. Await the insurer’s decision

You can accelerate this process by calling your prescriber’s office promptly and confirming that they received the PA request notification. Delays often happen when the prescriber’s office does not receive timely notification or does not have the insurer’s PA form and requirements readily at hand.

Decision timelines

Federal and state rules set minimum timeline requirements for PA decisions. The table below summarizes key frameworks:

Coverage type	Standard PA timeline	Urgent PA timeline
Medicare Advantage	7 calendar days	72 hours
ACA marketplace plans	15 calendar days	72 hours
Medicaid (managed care)	14 calendar days	72 hours
Commercial/employer plans	Varies by state (commonly 5–15 days)	24–72 hours (varies by state)

An urgent PA applies when the standard timeline could seriously jeopardize your health or ability to function. Your prescriber must indicate urgency and provide clinical rationale. If the insurer does not respond within the required window, rules in some states treat the request as approved by default; check your state’s insurance regulations.

When you can get a short-term fill during a pending PA

Some states require insurers to allow pharmacists to dispense an emergency or transition supply of a medication while a PA is pending, particularly for maintenance medications. The typical emergency supply is 72 hours to 30 days depending on the state. Ask your pharmacist directly whether this applies in your state and whether your insurer follows this policy. If you are switching insurers and were previously on a PA-approved drug, ask your new insurer whether a transition fill is available while they process your new PA request.

Documents and terms you’ll see

When navigating a prior authorization, these terms appear in insurer communications and coverage documents:

• Prior authorization — the requirement itself; appears on your Explanation of Benefits as a reason for denial if not obtained, and on your formulary as a flag next to drugs that require it
• Step therapy — a related requirement that you try specified alternatives before the requested drug will be approved; insurers typically want documentation that those alternatives were tried or are contraindicated
• Formulary exception — a request distinct from PA that allows a non-formulary drug to be covered; may run alongside or independently of a PA request
• Appeal — the process for challenging a PA denial; your insurer must notify you of the denial reason and your appeal rights

What to do when a prior authorization is denied

A PA denial is not the end of the road. Your insurer must send you a written denial notice explaining why coverage was denied. You have the right to:

File an internal appeal. Submit a formal challenge to the insurer, typically with additional supporting documentation from your prescriber. Internal appeal decisions generally must be made within 30 to 60 days for standard appeals and 72 hours for urgent appeals.

Request an external review. If your internal appeal is denied, you can request independent external review. An external review organization — not affiliated with your insurer — evaluates the case. For expedited external reviews (urgent clinical situations), decisions are typically required within 72 hours.

Request a formulary exception. If the denial is because the drug is non-formulary, your prescriber can document that formulary alternatives are not medically appropriate for you.

Ask your prescriber about step therapy exemptions. Many states have laws limiting step therapy and providing exemption pathways when you have already tried alternatives, the alternatives are contraindicated, or the required step therapy would cause significant delay in care.

Pursue patient assistance programs. If coverage is unavailable and you cannot afford the drug, ask your prescriber and the drug manufacturer about patient assistance programs that provide free or reduced-cost access.

Practical steps to minimize PA delays

• When your prescriber writes a new prescription for a drug that commonly requires PA, ask them to verify the PA requirement before you go to the pharmacy. Many electronic prescribing systems show formulary and PA status in real time.
• Ask your prescriber’s office to submit the PA request the same day the prescription is written.
• Follow up with both your prescriber’s office and your insurer two to three business days after the PA was submitted to confirm receipt and check status.
• Keep a record of PA request submission dates, reference numbers, and all communications — this documentation is valuable if you need to appeal.

The prior authorization and referrals guide covers PA requirements for specialist visits and procedures, which follow a related but somewhat different process from drug PA.