Your Drug's Coverage Changes Every January. Here Is What to Do Before Then.

Every insurance plan in the United States is permitted to revise its drug formulary once a year. The effective date for most of those revisions is January 1. If your drug is affected, your cost-sharing changes that day, your prior authorization requirements may change that day, and in some cases your drug may no longer be covered at all.

The window to find this out, and to act on it, closes before the end of the year.

What Formulary Changes Look Like

A formulary is the list of drugs a health plan covers, organized by tier. Tier placement determines what you pay. Tier 1 drugs typically carry the lowest cost-sharing; tiers 3, 4, and 5 progressively higher cost-sharing. Specialty tier drugs, in many plans, carry coinsurance of 20 to 30 percent with no out-of-pocket cap on that individual drug.

At each annual formulary update, plans can move drugs to higher tiers, remove them from the formulary entirely, add prior authorization requirements that did not previously apply, or impose step therapy, requiring you to try a different drug first before the plan will cover the one your physician prescribed.

These changes are not announced by press release. Under CMS regulations, plans must notify members of formulary changes that affect them at least 60 days before the change takes effect. In practice, that notice is often a multi-page document mailed with other plan communications in October or November. Most people do not read it closely, and the notification is not required to be written in plain language.

When to Check

For Medicare Advantage and Medicare Part D plans, the open enrollment window runs from October 15 to December 7 each year. ACA marketplace plans have an open enrollment window that runs from November 1 through January 15 in most states.

During these windows, you can switch plans without penalty. After they close, you generally cannot change coverage until the following year, with limited exceptions for qualifying life events.

The time to check your drug's formulary status is before these windows close, not after January 1.

To check: use your plan's online formulary search tool, or call member services and ask directly whether your drug is on the formulary for the upcoming plan year, at what tier, and whether any new prior authorization or step therapy requirements apply. If you use a specialty pharmacy, ask whether that requirement is changing, since some plans designate specific pharmacies for specialty drugs and change those designations at the annual update.

If you are considering a different plan during open enrollment, check the formulary for every plan you are evaluating before you enroll. The plan summary does not contain this information at the drug level. The plan's formulary document, which is a CMS-required public document, does.

If Your Drug Is Moving to a Higher Tier

A tier move does not mean you have no options.

Under CMS rules, if your drug has been moved to a higher cost-sharing tier and a clinically equivalent alternative is available at a lower tier, you can request a formulary tier exception. To do this, your prescribing physician must submit a statement explaining why the lower-tier alternative is medically inappropriate for you. Valid reasons include documented adverse reactions to the alternative, prior treatment failure, or a clinical condition that makes the lower-tier drug contraindicated.

The exception process varies by plan, but under ACA and CMS rules, plans must have a process for it, must notify you of your right to request one, and must respond to standard exception requests within 72 hours (or 24 hours for expedited requests when a delay would cause harm).

If the exception is denied, you have the right to appeal. The appeal follows the same process as a standard coverage denial appeal, with internal and external review options.

If Your Drug Is Removed From the Formulary

A formulary removal is the most disruptive change a plan can make, and it triggers specific protections.

If you are in the middle of a coverage period when you learn your drug will be removed on January 1, you do not have a right to continued coverage after that date under your current plan, unless you are on Medicare Part D.

For Medicare Part D members: CMS regulations provide that if a plan removes a drug from its formulary mid-year (outside the annual update), you are entitled to a temporary supply of up to 30 days to allow for transition or appeal. Annual formulary removals effective January 1 do not carry the same automatic supply right, but you may request a formulary exception or a transition fill from your pharmacy.

For commercial insurance: check whether your plan has a transition supply policy. Many do, typically 30 days, to give you time to appeal or switch to a covered alternative. Ask your pharmacy directly.

If your drug has been removed and there is no clinically equivalent alternative on the formulary, the exception process remains available. Your physician must document that no other covered drug is appropriate for your condition. CMS and state insurance regulators recognize this as a valid basis for exception in Medicare and many state-regulated plans.

Mid-Year Formulary Changes

Annual January updates are the most common formulary changes, but plans are permitted under CMS rules to add restrictions mid-year in limited circumstances, primarily when a drug receives a new FDA warning, when a biosimilar or generic becomes available, or when a drug is withdrawn from the market.

For Medicare Part D: if your plan adds a restriction to your drug mid-year, you are entitled to continue filling your current prescription at the previous cost-sharing level until the end of the plan year, provided you were already taking the drug at the time of the change. CMS regulations at 42 CFR 423.120 provide this protection. This is called the "mid-year change protection," and you should invoke it explicitly if your plan or pharmacy attempts to apply new restrictions to a refill.

For commercial plans regulated under the ACA, similar protections exist through the continuity-of-care provisions, though the specific rules vary by state.

The Annual Calendar

The practical summary, in order:

Before October 15: request your plan's upcoming formulary from member services, or check online. Confirm your drug's tier and any new requirements for the coming year.

During open enrollment (October 15 to December 7 for Medicare, November 1 to January 15 for ACA): if your drug has been removed or moved to a tier that significantly increases your costs, compare formularies across available plans before re-enrolling. The difference in tier placement can translate to thousands of dollars annually for specialty drugs.

Before December 31: if you are staying in your current plan and have identified a tier change or new PA requirement, contact your physician's office. A new prior authorization may need to be in place before your first fill of the year. If it is not, your January refill will be rejected at the pharmacy.

January 1: your plan year resets. Your deductible resets. Your out-of-pocket maximum resets. Any drug moved to a new tier is priced at the new tier from your first claim of the year.

The Notice Is Not the Protection

The CMS notification requirement exists to give you time to act. It does not act for you.

The formulary change notice does not file an exception request. It does not call your doctor. It does not find you a comparable plan during open enrollment. It informs you, in a document most people receive and set aside, that something is about to change.

The patients who navigate January formulary changes best are the ones who treat open enrollment as a task with a deadline, not as a passive renewal. Verify your drug. Verify the tier. Verify the requirements. Do it before the window closes.

Sources: CMS Medicare Part D Formulary Requirements, 42 CFR 423.120; CMS Prior Authorization and Formulary Exception Requirements for Medicare Advantage; ACA 45 CFR 147.138; CMS Guidance on Mid-Year Formulary Changes; Medicare Open Enrollment periods per CMS annual guidance.