Every year, millions of Medicare beneficiaries miss out on hundreds-or even thousands-of dollars in savings simply because they don’t review their prescription drug coverage. If you take one or more medications regularly, your current plan might be costing you more than it should. The Annual Open Enrollment Period (AEP) is your one chance to fix that. It runs from October 15 to December 7 each year, and any changes you make during this window take effect on January 1 of the next year. This isn’t just a formality. It’s a critical financial decision.
Why You Can’t Ignore This Period
Medicare plans change every year. That means your medications might move to a higher cost tier, your pharmacy could be removed from the network, or your monthly premium could jump. In 2025, 60% of Part D plans changed at least one medication’s formulary status. That’s not rare. That’s the norm. A drug covered at Tier 2 last year might be Tier 4 this year, meaning you pay 25-33% more out of pocket. The Medicare Rights Center found that 78% of Medicare Advantage plans altered their provider networks between 2023 and 2024. If your local pharmacy is no longer preferred, you’ll pay more-even if you don’t notice until you’re at the counter.And it’s not just about premiums. The Inflation Reduction Act fully closed the Part D coverage gap (the "donut hole") in 2025, but you still pay 25% coinsurance for brand-name drugs in the catastrophic phase. Meanwhile, insulin is capped at $35 per month, but only if your plan includes it in the formulary. If you’re on Ozempic, Mounjaro, or another GLP-1 drug, the difference between a plan that covers it at Tier 2 versus Tier 4 could be over $400 a month.
What You Can Change During Open Enrollment
You have five options during AEP:- Switch from Original Medicare (Parts A and B) to a Medicare Advantage plan (Part C)
- Switch from a Medicare Advantage plan back to Original Medicare
- Change from one Medicare Advantage plan to another
- Join a standalone Medicare Part D prescription drug plan
- Switch from one Part D plan to another
But you can’t do everything. If you’re on a Medicare Advantage plan, you can’t switch to a different one after December 7 unless it’s January 1-March 31 (the Medicare Advantage Open Enrollment Period). And that period only allows one switch. So if you make the wrong call in January, you’re stuck until next October.
Your Medication List Is Your Starting Point
Before you look at premiums or networks, you need a complete list of your medications. Not just names-dosages, frequency, and whether they’re brand or generic. If you take three pills a day, that’s 1,095 doses a year. A $10 difference per pill adds up to over $10,000 annually. That’s why Justice in Aging’s 2025 analysis found that people who reviewed their medications during AEP saved an average of $532 on prescriptions alone.Get your list from your pharmacy, your doctor, or your personal health record. Write it down. Don’t rely on memory. Many beneficiaries forget one medication, only to realize later that it’s now on a specialty tier with a $200 copay.
Get Your Annual Notice of Change (ANOC)
Your current plan must send you an ANOC by October 1. This document tells you exactly what’s changing in your plan for next year: new premiums, higher deductibles, formulary changes, pharmacy network updates, and new cost-sharing rules. Read it. Don’t toss it. If you didn’t get it, call your plan. If you’re enrolled in a Medicare Advantage plan, you’ll also get an Evidence of Coverage (EOC)-that’s your full contract. Both are critical.One beneficiary in Ohio didn’t open her ANOC until November. She found out her $400/month medication had moved to Tier 4. She had to pay $300 more per month than she expected. She switched plans after the deadline and was stuck with her old plan for another year.
Use the Medicare Plan Finder Tool
Go to Medicare.gov/plan-compare. Type in your medications, dosages, and preferred pharmacy. The tool will show you every plan available in your area and calculate your estimated annual drug costs. You’ll see:- Monthly premium
- Annual deductible
- Cost per pill at each tier
- Pharmacy network (preferred vs. standard)
- Out-of-pocket maximum
- Specialty drug restrictions
The tool doesn’t guess. It uses your exact data. In 2024, beneficiaries who used the tool were 3.2 times more likely to find a lower-cost plan than those who didn’t. One woman in Texas saved $1,200 a year by switching from a $117 plan with Tier 4 coverage to a $38 plan with Tier 2 coverage for her diabetes meds.
Check Your Pharmacy Network
A plan might have a low premium, but if your pharmacy isn’t in-network-or worse, it’s moved from preferred to standard-you’ll pay more. In October 2024, 32 Reddit threads from r/medicare mentioned their pharmacy was removed from the network. One man in Florida had to drive 45 minutes to his preferred pharmacy after his plan changed. He ended up switching plans because he couldn’t afford the extra $15 per prescription.Always verify your pharmacy is listed as "preferred" in the plan details. Preferred pharmacies mean lower copays. Standard pharmacies mean higher ones. And some plans don’t cover out-of-network pharmacies at all.
Watch for Formulary Restrictions
Many plans use prior authorization, step therapy, or quantity limits to control costs. That means:- Prior authorization: Your doctor must get approval before the plan covers your drug
- Step therapy: You must try a cheaper drug first before they’ll cover yours
- Quantity limits: You can only get a 30-day supply, even if your doctor prescribes 90 days
These rules can delay care or force you to switch medications. KFF’s 2024 analysis found that 50% of covered drugs had some form of utilization management. If your drug requires prior authorization and your doctor won’t do the paperwork, you’re out of luck.
Don’t Forget Supplemental Benefits
Some Medicare Advantage plans offer extra perks: dental, vision, hearing, gym memberships, or transportation. But if you’re dual-eligible (Medicare and Medicaid), 31% of these plans have hidden restrictions. Justice in Aging found that many beneficiaries didn’t realize their supplemental benefits were tied to income or residency rules. If you need transportation to the pharmacy, make sure the plan actually provides it-and that you qualify.
Deadline Is December 7
Changes must be submitted by December 7. If you wait until December 8, you’re locked into your current plan for another year. CMS data shows 12% of first-time Medicare users miss this deadline. Don’t be one of them. Set a calendar reminder. Mark it on your wall. Tell a family member. If you’re unsure, call 1-800-MEDICARE or visit your local State Health Insurance Assistance Program (SHIP). There are 9,400 certified counselors ready to help for free.Common Mistakes and How to Avoid Them
- Mistake: Only comparing premiums. Fix: Look at total annual cost-premiums + copays + deductibles.
- Mistake: Assuming your plan is "good enough." Fix: Even if you’ve been with the same plan for 10 years, review it every year.
- Mistake: Not checking if your medications are still covered. Fix: Cross-check your list against the new formulary.
- Mistake: Waiting until the last week. Fix: Start October 15. You have three weeks. Use them.
One of the most common tips from Reddit users? "Download your ANOC first. Then compare formulary changes before looking at premiums." That’s the smart way.
What’s New in 2026
Starting January 1, 2026, Medicare Advantage plans must cover all Part B drugs administered in outpatient settings. That means more medications will be included under your plan’s drug coverage. The Medicare Plan Finder tool will also add a "total cost" calculator that estimates your annual drug spending based on your exact regimen. This is a big upgrade. It’s no longer about guessing-you’ll know exactly how much you’ll pay.But premiums are expected to rise 4.2% in 2026 due to new drug pricing rules. That’s why planning now matters even more. The more you lock in now, the less you’ll pay later.
What happens if I don’t make a change during Open Enrollment?
If you don’t change anything, you’ll automatically stay in your current plan for the next year. But that doesn’t mean your costs stay the same. Your plan may raise premiums, change formularies, or remove your pharmacy from the network. You’ll still pay whatever your plan charges-without having had a say in it.
Can I switch Part D plans more than once a year?
No. You can only switch Part D plans during the Annual Open Enrollment Period (October 15-December 7). The only exception is if you qualify for a Special Enrollment Period-for example, if you move out of your plan’s service area, lose other coverage, or enter a nursing home. Otherwise, you’re locked in until next October.
Do I need to re-enroll in Medicare Part D every year?
No. If you’re already enrolled in a Part D plan and don’t switch, your coverage continues automatically. But you should still review your plan each year because costs and coverage can change. Automatic renewal doesn’t mean automatic savings.
What if my medication is removed from the formulary?
If your medication is removed, your plan must give you at least a 30-day transition supply so you can get your doctor to prescribe an alternative or file an exception request. But you’ll pay more out of pocket during that time. The best move is to find a new plan that covers your drug before the change takes effect.
How do I know if a plan covers my specific pharmacy?
Use the Medicare Plan Finder tool. Enter your pharmacy’s name and ZIP code. The tool will show you which plans include that pharmacy and whether it’s preferred (lower cost) or standard (higher cost). You can also call the pharmacy directly and ask which Medicare plans they accept.
Are there penalties for dropping Part D coverage?
Yes. If you drop Part D and don’t have other creditable drug coverage (like from an employer or VA), you’ll pay a late enrollment penalty when you re-enroll. The penalty is 1% of the national base premium for each month you go without coverage. For 2025, that’s $34.70 x 1% = $0.35 per month for each month without coverage. It adds up over time.
Next Steps: What to Do Right Now
1. Collect your medications. Write down every drug you take, including over-the-counter ones if you’re on a daily regimen. 2. Find your ANOC. Check your mail or log into your plan’s website. If you don’t see it, call them. 3. Go to Medicare.gov/plan-compare. Enter your drugs and pharmacy. Compare at least three plans. 4. Call SHIP. Find your local State Health Insurance Assistance Program at shipto.org. They offer free, one-on-one help. 5. Enroll by December 7. Don’t wait. Your future self will thank you.Medicare doesn’t get cheaper on its own. You have to make it cheaper. This is your moment.
