What Happens to Your Drug List Each Year
Every fall, Medicare Part D plans update their formularies. A formulary is the official list of drugs a plan covers. These lists change every year, and sometimes the changes affect your medications.
Your plan might drop a drug entirely. It might move a drug to a higher cost-sharing tier—meaning you pay more. Or it might add new drugs, lower costs on others, or require prior approval for drugs you've been taking freely. These shifts happen because drug prices change, new medications hit the market, and plans adjust their coverage to manage costs.
The good news: you don't have to guess. Plans must publish their new formularies before the enrollment period starts in October. You can review yours well before you need to make a decision.
When Formulary Changes Take Effect
New Part D formularies go into effect on January 1st each year. The plans post their updated drug lists online in early October, typically by the first week of the month. That gives you time to review your medications before the Annual Enrollment Period (AEP) begins on October 15th.
If your current plan's new formulary affects a drug you take regularly—either by removing it, raising its cost, or adding restrictions—you'll want to know before January arrives. That way, you can switch plans during AEP if a different plan covers your medications better.
What Changes Look Like in Practice
A formulary change might mean:
- Your blood pressure medication moves from the lowest cost tier to a higher one.
- Your diabetes drug is no longer covered at all, and you'd need to switch to a different medication your plan approves.
- A drug you use requires prior approval now—meaning your doctor must request permission from the plan before you can fill it.
- A new generic version of your medication becomes available, and your plan offers better pricing on it.
- Your plan adds a drug you've been paying out-of-pocket for, bringing it into coverage.
Some changes help you. Some cost you more. The only way to know is to check.
How to Review Your Formulary Before October
Start with the medications you take every day. Write down the name of each one, the strength (like 10mg), and how often you take it.
Next, find your plan's updated formulary when it's published in early October. Your plan makes this information available online in a searchable format. You can look up each of your drugs one at a time.
For each medication, check:
- Is it still on the formulary?
- What tier is it on? (Tiers determine your cost-sharing level.)
- Does it require prior approval or step therapy? (Step therapy means you may need to try a cheaper drug first.)
- Is there a generic version available, and does your plan cover it?
Write down what you find. If a drug you rely on is no longer covered, or if its tier has moved up significantly, that's a signal to explore other plans.
Red Flags to Watch For
Pay special attention if:
- A drug you take regularly is being removed from the formulary entirely.
- A medication moves to a tier with higher cost-sharing.
- Your plan adds new restrictions, like requiring prior approval for a drug you've been using without one.
- You take multiple medications, and the formulary changes affect more than one of them.
If any of these apply, comparing other plans during AEP might save you money or ensure your medications stay covered without extra hassle.
Specialty Drugs and Brand-Name Medications
If you take a specialty drug—a high-cost medication for conditions like rheumatoid arthritis, cancer, or hepatitis C—formulary changes are especially important to monitor. Specialty drugs often sit on the highest cost-sharing tier, and coverage can shift year to year.
Brand-name drugs also change frequently as generics become available. Your plan might encourage you to switch to a generic version by covering it at a lower tier. If you prefer the brand name, you may have the option to stay on it, but your cost-sharing may be higher.
Plan Your Review Timeline
Early October is the ideal time to start. Here's a simple rhythm:
- Early October: Plans publish new formularies. Review your medications against your plan's updated list.
- Mid-October: If you find problems, use that information to compare other plans.
- October 15–December 7: AEP runs. You can switch plans if you've found a better fit.
- January 1: Your new plan (or your current plan) takes effect with the updated formulary.
This timeline gives you about two weeks to investigate before you need to make a change. That's usually enough time to make a calm, informed decision.
When Formulary Changes Don't Require Action
Not every formulary change means you need to switch plans. If your medications stay on the same tier and no new restrictions appear, you're likely fine staying put. The goal is to catch the changes that *do* affect you—not to worry about changes that don't.
Also remember: even if your plan's formulary changes, you only need to switch if the change actually impacts the drugs you use. Generic alternatives or slightly lower-tier options might work just as well for you. That's a conversation between you, your doctor, and your plan's coverage details.
A Simple Checklist
Before the enrollment period ends:
- [ ] List every medication you take regularly.
- [ ] Check your plan's 2025 formulary for each drug.
- [ ] Note any drugs that are dropped, moved to a higher tier, or have new restrictions.
- [ ] If changes affect you, compare a few other plans to see if they cover your medications better.
- [ ] If you switch, make your change during AEP (October 15–December 7).
The Takeaway
Formularies change every year, but you're not at the mercy of those changes. By reviewing your plan's updated drug list in early October, you can spot problems before they happen and make a switch if you need to. A little homework in October can prevent surprises—or higher costs—when the new year begins.
We do not offer every plan available in your area. Any information we provide is limited to the plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. Not connected with or endorsed by the U.S. government or the federal Medicare program.