How Formulary Changes Mid-Year Can Affect Your Prescription Coverage

Why Formularies Change Mid-Year

Most consumers assume that once they select a health plan during open enrollment, their prescription coverage stays fixed for the entire year. That assumption is largely wrong. Insurers negotiate contracts with pharmaceutical manufacturers on an ongoing basis, and when those negotiations shift, the formulary shifts with them.

There are several common reasons your plan's drug list might change between January and December:

• New generic drugs enter the market. When a brand-name drug's patent expires and a generic becomes available, insurers often remove the brand-name version from lower tiers or drop it entirely, directing members toward the cheaper equivalent.
• Manufacturer rebate agreements change. Insurers receive rebates from drugmakers in exchange for preferred formulary placement. If a competing manufacturer offers a better deal, the original drug may be deprioritized or removed.
• FDA safety actions. If a drug is recalled or receives a new black-box warning, plans may remove it immediately, sometimes without advance notice.
• New clinical evidence emerges. A drug once considered standard of care may be displaced by a newer treatment that the plan now favors.
• Cost management strategies. Insurers periodically restructure their tier systems to manage overall plan costs, which can push previously affordable drugs into higher, more expensive tiers.

Understanding these drivers helps you interpret any notice you receive — and anticipate changes before they catch you off guard at the pharmacy counter.

Your Legal Rights When a Formulary Changes

Federal regulations provide meaningful — though not absolute — protections when insurers alter their formularies. Knowing these rights puts you in a stronger position to push back or find alternatives quickly.

The 60-Day Advance Notice Requirement

Under federal rules, non-grandfathered health plans sold in the individual and small-group markets must give enrollees at least 60 days' written notice before removing a covered drug from the formulary or moving it to a higher cost-sharing tier. This notice must be clear and include information about what alternatives are available on the plan's formulary.

However, there are important exceptions. Plans may make immediate formulary changes — without advance notice — when:

• The FDA issues a safety recall or new safety information that warrants urgent action.
• A generic equivalent becomes available and the plan substitutes it for the brand-name drug at the same or lower cost-sharing level.
• The manufacturer voluntarily withdraws the drug from the market.

The Right to an Exception or Appeal

Every ACA-compliant plan must have a formal exception and appeals process. If your medication is dropped or moved to a tier that makes it unaffordable, you have the right to:

1. Request a formulary exception: Ask the plan to cover your specific drug, or to apply a lower-tier cost-sharing level, based on medical necessity documented by your prescriber.
2. File an internal appeal: If your exception request is denied, you can appeal the decision through the plan's internal review process.
3. Request an external review: If the internal appeal fails, you have the right to an independent external review, conducted by an organization that has no financial relationship with your insurer.

Your insurer must respond to standard exception requests within 72 hours for non-urgent situations and within 24 hours for urgent or expedited requests. Deadlines for appeals vary but are strictly regulated.

State insurance commissioners sometimes enforce additional protections beyond these federal minimums. Some states require plans to honor a 30- to 90-day supply of a removed medication while an exception is pending — what's called a "transition supply." This prevents a dangerous gap in treatment while the bureaucratic process unfolds.

How to Find Out About Formulary Changes

Waiting to find out at the pharmacy that your medication is no longer covered is one of the most stressful — and avoidable — situations in managing prescription coverage. A proactive approach significantly reduces that risk.

Check for Mailed and Electronic Notices

Your insurer is required to notify you about significant formulary changes, but notices can be easy to overlook. Check your email spam folder, your insurer's member portal inbox, and your physical mailbox, especially if you receive Explanation of Benefits documents by mail. Do not assume silence means no changes.

Use Your Insurer's Drug Lookup Tool

Most insurer websites have a formulary search tool where you can enter the name of any prescription drug and immediately see its current tier status, any quantity limits, step therapy requirements, or prior authorization flags. Make a habit of checking your key medications:

• Before the plan year begins (typically in November or December)
• When you receive any plan communication, even routine ones
• If your pharmacist or doctor mentions anything about coverage changes
• Whenever you start a new prescription

Ask Your Pharmacist

Pharmacists are often the first to know when a drug's coverage status changes, because they see the rejection codes in real time when processing claims. Build a relationship with your pharmacy team and ask them to flag any coverage changes they notice for your regular prescriptions.

Review the Annual Notice of Change

If you are enrolled in a Medicare Advantage or Part D plan, federal rules require your plan to send an Annual Notice of Change (ANOC) by September 30 each year, detailing all formulary changes taking effect January 1. Read this document carefully — it is not junk mail. For more on how Part D formularies work, see our guide to Medicare Part D prescription drug coverage.

Steps to Take When Your Medication Is Affected

Acting quickly and strategically when you receive a formulary change notice gives you the best chance of maintaining affordable access to your medication. Here is a step-by-step approach:

Step 1: Verify the Change

Before doing anything else, confirm exactly what changed. Call member services or use the online drug lookup tool to determine:

• Was the drug removed entirely, or moved to a different tier?
• Are there new prior authorization or step therapy requirements?
• Is there a covered generic or biosimilar alternative?

Step 2: Talk to Your Prescriber

Your doctor is your most important ally in this process. Notify them of the formulary change immediately and ask:

• Is there a therapeutic alternative already on the plan's formulary that could work for your condition?
• If not, are they willing to submit a formulary exception request on your behalf, documenting why the specific drug is medically necessary?

Step 3: Request a Formulary Exception

If no adequate alternative exists, your prescriber should submit a formulary exception request with supporting clinical documentation. This typically includes your diagnosis, treatment history, and evidence that alternative drugs were tried and failed, or are contraindicated.

“A formulary exception is not a long shot — it is a legitimate, regulated process that plans are required to have. When a physician documents clearly why a specific drug is the only appropriate option for a patient, exception requests succeed far more often than people assume.”

— Stacie Dusetzina, Professor of Health Policy, Vanderbilt University School of Medicine, and formulary research expert

Step 4: Explore Manufacturer Assistance Programs

Many pharmaceutical manufacturers offer patient assistance programs (PAPs) or co-pay cards that can offset the cost of a medication while your exception or appeal is pending. These programs are particularly common for specialty drugs. Ask your doctor's office or check the manufacturer's website directly.

Step 5: Consider Plan Changes at Your Next Opportunity

If formulary issues are recurring or your medication is chronically difficult to access through your current plan, use your next open enrollment period to switch to a plan with better formulary coverage for your needs. Our article on switching health plans during open enrollment explains what to compare and what resets when you make the move.

Keep in mind that formulary changes can also affect your overall cost burden. Shifts in tier placement directly affect your cost-sharing — the copays and coinsurance you owe. Understanding how your premiums, deductibles, and out-of-pocket maximums interact with formulary tiers helps you model the true annual cost of your prescriptions before and after a change.

Special Situations: Medicare Part D and Mid-Year Enrollment

Medicare Part D plans have their own specific rules around mid-year formulary changes, and they are worth understanding separately because the stakes and the options differ from commercial insurance.

Mid-Year Changes in Part D

Part D plans must generally maintain the same formulary from January 1 through the end of the plan year. They are not permitted to remove a drug from a protected class (such as antidepressants, anticonvulsants, or immunosuppressants) mid-year if you are already taking it. For other drug categories, mid-year changes are permitted with appropriate notice, and the plan must provide a transition supply — typically a 30-day emergency fill — while you resolve the situation.

Special Enrollment Periods Triggered by Formulary Changes

Unlike commercial plans, Medicare Part D enrollees may qualify for a Special Enrollment Period (SEP) if their plan makes a significant formulary change that affects a medication they are currently taking. This SEP allows them to switch to a different Part D plan mid-year rather than waiting until Annual Enrollment (October 15 – December 7). If you think a mid-year formulary change might qualify you for an SEP, contact Medicare directly at 1-800-MEDICARE or visit medicare.gov. You can also review our article on adding Part D to your Medicare coverage mid-year for context on how mid-year enrollment works more broadly.

The Low Income Subsidy (Extra Help) Protections

Medicare beneficiaries who qualify for the Low Income Subsidy — also called Extra Help — have additional formulary protections. Their plan generally cannot restrict access to a needed drug mid-year, and if a formulary change affects them, they are entitled to a transition supply for the full remaining months of the calendar year. These protections recognize that individuals with limited income are least able to absorb sudden out-of-pocket cost increases.

Practical Tips for Staying Ahead of Formulary Changes

Prevention is always easier than crisis management. These practical habits can help you avoid being blindsided by a formulary change.

Keep a current medication list. Maintain an updated list of every prescription you take, including the exact drug name (brand and generic), dosage, and prescriber. This makes it much faster to verify formulary status or discuss alternatives with your doctor.

Opt in to electronic communications. Insurers often send formulary notices by email before paper letters arrive. Make sure your contact information in the member portal is current, and that plan emails are not being filtered as spam.

Review your Summary of Benefits and Coverage annually. Even if your plan renews automatically, take 20 minutes each fall to compare the formulary to the one you enrolled in. Pay attention to any drugs in tiers 3, 4, or 5 — specialty and non-preferred drugs that carry the highest cost-sharing.

Ask about step therapy requirements before starting a new medication. Step therapy requires you to try one or more lower-cost alternatives before the plan will cover a more expensive drug. Knowing this upfront prevents surprises and helps your doctor choose the most coverage-friendly treatment approach from the start.

Document everything. If you pursue an exception or appeal, keep copies of all correspondence, note the date and name of every phone representative you speak with, and save any written denial letters. This documentation is essential if you escalate to external review or a state insurance department complaint.

Staying informed is ultimately the most powerful tool you have. Formulary changes are a routine feature of the U.S. health insurance market — not a surprise attack — but they require active management on your part to navigate successfully.