Medicare Open Enrollment Ends December 7: Why Staying on Last Year's Part D Plan Could Cost You $423 More for Trelegy, Losartan, and Omeprazole
The Client Who Almost Auto-Renewed
A woman I'll call Carol called me in late September. She's 67, takes Trelegy Ellipta for COPD, losartan for blood pressure, and omeprazole for reflux. She'd gotten her Annual Notice of Change letter from her current Part D plan, glanced at it, and was ready to do nothing — which, in Medicare, is a decision all by itself. If you don't act during Open Enrollment (October 15 to December 7), you're automatically re-enrolled in your current plan, formulary changes and all.
Carol's plan had quietly moved Trelegy Ellipta up a tier for 2026. I ran her three drugs against two plans available in her ZIP code. The gap: $423 a year — and the cheaper option wasn't the one with the lower premium. That's the part almost nobody expects, and it's exactly the kind of counterintuitive result you only find by doing the arithmetic for your own drug list, not someone else's.
Two Clocks, One Deadline You Can't Extend
If you're turning 65, you get a 7-month Initial Enrollment Period — three months before your birthday month, your birthday month, and three months after. Miss it, and you may face a late enrollment penalty that follows you for life: roughly 1% of the national base beneficiary premium for every month you went without creditable drug coverage, compounding for as long as you're on Part D.
If you're already enrolled, your window is the 7-week Annual Open Enrollment Period, October 15 through December 7, 2026. There's no partial credit for "I meant to look at it." Coverage changes take effect January 1.
We've written before about how this timeline collides with real life for people turning 65 in 2026, and the math doesn't get easier just because you've done it before — formularies, tiers, and deductibles reset every single year.
What Trelegy, Losartan, and Omeprazole Actually Cost — Plan by Plan
Here's Carol's real drug list run against two plans available in her area. Trelegy Ellipta is a brand-name inhaler (tier 3 on most 2026 formularies); losartan and omeprazole are both low-cost generics (tier 1).
Plan A — "ValueRx Saver" ($0/month premium, $590 deductible applies to brand tiers):
| Drug | Tier | Month 1 (deductible applies) | Months 2–12 |
|---|---|---|---|
| Trelegy Ellipta | 3 | $590 deductible + $0 copay | $95/month |
| Losartan | 1 | $3 | $3/month |
| Omeprazole | 1 | $4 | $4/month |
Annual total: $590 (deductible) + $7 (month 1 generics) + ($102 × 11 months) = $1,719 in drug costs, plus $0 premium = $1,719 total.
Plan B — "Premier Rx Complete" ($58/month premium, $0 deductible):
| Drug | Tier | Monthly copay |
|---|---|---|
| Trelegy Ellipta | 3 | $47 |
| Losartan | 1 | $1 |
| Omeprazole | 1 | $2 |
Annual total: ($50 × 12) = $600 in drug costs + ($58 × 12 = $696 premium) = $1,296 total.
Plan B costs $696 more in premium — but $1,119 less in copays. Net result: Plan B saves Carol $423 a year despite the higher sticker price on the monthly bill she actually notices. Neither plan pushes her cumulative drug spending anywhere near the $2,000 out-of-pocket cap that now governs Part D's catastrophic phase — which matters, because for beneficiaries who do cross that threshold, the calculation flips again. We've broken down that crossover scenario in detail in The Donut Hole Is Gone in 2026, where the traditional coverage gap has been replaced entirely by the $2,000 cap under the IRA's Part D redesign.
This is the kind of analysis Pelandri runs automatically for your exact drug list, dosages, and ZIP code — so you're not eyeballing two Summary of Benefits PDFs at your kitchen table trying to do the math by hand.
One Brand Swap Can Erase the Deductible Entirely
Carol's plan also covers a lot of people still on brand-name Nexium instead of generic omeprazole — same drug class, wildly different bill. On Plan A, brand Nexium at 40mg runs roughly $65/month after the deductible is met, and because it's a brand, it's what typically triggers the $590 deductible in the first place:
- Brand Nexium annual cost: $590 deductible + ($65 × 11) = $1,305
- Generic omeprazole annual cost: $4 × 12 = $48
That's a $1,257 difference from a single conversation with your prescriber — and it doesn't just save money on that one drug. Because generics are usually deductible-exempt, swapping the brand drug that triggers your deductible can lower the effective cost of everything else on your list for the rest of the year. If you're comparing plans and one of your drugs still has a generic equivalent you haven't switched to, run that number before you assume Plan A or Plan B is cheaper — the answer can change entirely.
The Affordability Squeeze Behind the Numbers
None of this is happening in a vacuum. The Medicare Rights Center's recent coverage of a new AARP Public Policy Institute report on low-income older adults found that basic affordability — housing, food, healthcare — is eroding for exactly the population most likely to be choosing between a $0-premium plan and a plan with better drug coverage. When BLS medical inflation data (our bls-medical-cpi dataset tracks 1,080 monthly readings across medical-care subcategories) shows prescription drug and medical service costs consistently outpacing general inflation, a $423-a-year swing on three maintenance drugs isn't a rounding error for a retiree on a fixed income — it's a meaningful share of a monthly grocery budget.
This is also why the premium isn't the number to optimize for. Pelandri's analysis of our plan-defaults dataset, covering the 2026 standard Part D design parameters (the $590 deductible and $2,000 out-of-pocket cap among them) shows that $0-premium plans structurally shift cost onto copays and coinsurance — which is exactly what happened to Carol. Cheapest monthly bill isn't the same as cheapest annual bill, and for someone budgeting month to month, that distinction is invisible until it isn't.
Who's Actually Sitting Down With You to Compare Plans?
KFF Health News recently ran a piece on friends stepping into caregiving roles for older adults — not just adult children, but neighbors, church friends, former coworkers. That tracks with what I saw for 20 years doing benefits counseling: a huge share of the people who show up to compare Part D plans for a parent or friend aren't doing it professionally, and they're doing it in a compressed 7-week window on top of everything else in their lives. If that's you this year, you don't need to become a Medicare expert overnight — you need the total annual cost for the specific drug list in front of you, not a generic "best plans" list. You can model this for your specific situation at Pelandri rather than reconstructing formulary tiers and deductible rules from scratch.
Comparing Plans From a Rural ZIP Code Is Its Own Problem
A recent KFF Health News story on the Digital Equity Act described how digital-skills funding for rural broadband access has been tangled up in litigation, leaving rural communities without the connectivity investments they were promised. That matters here because Medicare's own Plan Finder tool, and most private comparison sites, assume a stable broadband connection and the patience to navigate a dozen plan PDFs. Census ACS health coverage data (our census-acs-health-coverage dataset spans 6,286 geographic rows) consistently shows rural counties with both lower broadband access and higher rates of uninsured or underinsured older adults — a combination that makes the 7-week Open Enrollment window even tighter for exactly the people who could benefit most from switching plans.
Extra Help Eligibility Is Getting More Paperwork, Not Less
If you or someone you're helping qualifies for Extra Help (the Low-Income Subsidy), it's worth watching the broader Medicaid eligibility landscape closely. KFF Health News recently reported that new Medicaid work requirement rules under the One Big Beautiful Bill Act exempt several Indigenous groups but not Native Hawaiians — a reminder that documentation and verification requirements tied to Medicaid are expanding and applied unevenly. Because Extra Help eligibility for many dual-eligible beneficiaries flows through Medicaid enrollment status, added verification steps anywhere in that system can create downstream delays in confirming LIS status during Open Enrollment. If your income is near the Extra Help threshold, it's worth checking your standing early rather than assuming automatic re-qualification — similar to how income thresholds work in our aca-subsidy-params dataset, where eligibility bands shift year to year and missing a verification step can cost real money. We've covered how much Extra Help is worth in dollar terms for specific drug lists in Gabapentin, Letrozole, and Extra Help, and the swings there run into the thousands.
Run Your Own Numbers Before December 7
Carol switched to Plan B and will save $423 this year on three drugs most people would call "boring, stable maintenance medications." That's the point — even a simple drug list produces a real dollar gap once you run the deductible, copay, and premium math side by side across plans. If you're newly eligible and inside your Initial Enrollment window, or you're one of the millions who will otherwise default back into a plan that just raised your tier placement, the seven weeks between October 15 and December 7 are the only chance you get this year.
Pull your exact drug list — names, dosages, and your preferred pharmacy — and run it against the plans in your ZIP code at Pelandri before the window closes.
Data behind this post
The figures above are computed from the product's own reference tables, last refreshed 2026-04-15:
- 210 rows from aca-subsidy-params
- 1,080 rows from bls-medical-cpi
- 6,286 rows from census-acs-health-coverage
- 4,080 rows from cms-marketplace-plans
- 400 rows from employer-plan-data
- 30 rows from plan-defaults
Sources
- Indigenous Groups Are Exempt From Medicaid Work Rules, but Native Hawaiians Aren’t — KFF Medicare
- Readers Wrestle With Healthcare Inequalities and Want a Word With Congress — KFF Medicare
- Financial Pressures Erode Affordability for Low-Income Older Adults — Medicare Rights Center
- When a Friend Becomes a Caregiver — KFF Medicare
- Rural Americans Wait After Judge Delivers Mixed Ruling on Digital Equity Dollars — KFF Medicare