Rosuvastatin at $3/Month vs. Crestor at $2,216/Year: How Formulary Tiers Decide Your 2026 Part D Bill While Washington Debates Healthcare Affordability
I spent twenty years telling people at the Area Agency on Aging the same thing every fall: "The pill is the same. The plan is what's different." Nowhere is that clearer than with a drug most of you take without thinking twice about — rosuvastatin, the generic version of Crestor.
Here's the scenario I want to walk through, because I've watched it play out at kitchen tables more times than I can count. You have high cholesterol. Your doctor either has you on brand-name Crestor because you started it years ago and never switched, or you're already on the generic and assume every Part D plan treats it the same way. Neither assumption is safe. Based on Pelandri's analysis drawing on CMS's cms-marketplace-plans dataset (4,080 plan records) and plan-defaults data covering formulary structures, the same 20mg rosuvastatin prescription can cost $3 a month on one plan and $14 a month on another — and that gap gets much bigger once you factor in how each plan handles its deductible.
The two plans, side by side
Let's use two representative 2026 Part D plans — I'll call them Plan A ("LowPremium Rx Saver," $18/month premium) and Plan B ("ValueRx Complete," $42/month premium) — and run your annual cost for both the brand and the generic version of the same drug.
| Plan A ($18/mo premium) | Plan B ($42/mo premium) | |
|---|---|---|
| Rosuvastatin (generic), Tier placement | Tier 1, preferred generic — deductible waived | Tier 2, non-preferred generic — deductible applies |
| Rosuvastatin (generic) copay | $3/fill | Full retail (~$12/fill) until deductible met |
| Annual cost, generic only | $252 | $648 |
| Crestor (brand), Tier placement | Tier 3, non-preferred brand | Tier 3, non-preferred brand |
| Crestor (brand) coinsurance | 25% after deductible | 25% after deductible |
| Annual cost, brand only | $2,216 | $2,504 |
Two things jump out, and they're the two lessons every Medicare beneficiary needs walking into Open Enrollment.
Lesson one: for cheap generics, the deductible design matters more than the copay you see on the summary of benefits
Plan A waives its $590 deductible for Tier 1 drugs, so your $3 copay starts on your very first fill in January. Plan B applies its deductible to Tier 2 drugs — and here's the part almost nobody reads in the Evidence of Coverage: if your drug's retail price never gets you to $590 in a year, you never get out of the deductible phase. You just keep paying full retail, month after month, for a "generic" that the plan's own drug list still calls affordable.
At roughly $12 a fill, twelve months of rosuvastatin on Plan B comes to $144 — not the $14 copay printed in the formulary summary, because you never accumulate enough spending to trigger that copay tier. Add the $504 premium and you're at $648 a year for a drug that costs $252 a year on Plan A. That's a $396 annual difference for the exact same pill, same dose, same pharmacy chain — driven entirely by formulary tier placement and deductible design, not drug price. This is the same mechanism I walked through with a different generic combination in Rosuvastatin, gabapentin, and omeprazole — the pattern repeats across nearly every maintenance generic on the market.
Lesson two: once you're going to hit the $2,000 cap anyway, the premium decides the rest
Brand-name Crestor tells a different story. At an estimated $550-per-month list price, you blow through the $590 deductible in the first month and a half, then pay 25% coinsurance until your true out-of-pocket spending (what Medicare calls TrOOP — your true out-of-pocket costs) reaches the $2,000 annual cap that took effect under the Inflation Reduction Act. Run the month-by-month math and you land on the cap right around month 12 on both plans — meaning your drug costs converge near $2,000 regardless of which plan you pick.
When that happens, the premium becomes the deciding variable, not the copay structure. Plan A costs $2,216 for the year on brand Crestor ($216 premium + ~$2,000 in cost-sharing). Plan B costs $2,504 ($504 premium + ~$2,000). That's a $288 gap driven almost entirely by the monthly premium — the exact dynamic I detailed for a different drug combination in Medicare's $2,000 drug cap explained. Once your drug list is expensive enough to guarantee catastrophic-phase spending, shopping for the lowest premium plan that still covers your drugs at a reasonable tier is usually the higher-value move.
The real number: switching brand to generic
Here's the number that should stop you mid-scroll. Switching from brand Crestor to generic rosuvastatin saves you $1,964 a year on Plan A and $1,856 a year on Plan B. That dwarfs anything you can do by shopping plans alone. If you're currently on the brand and haven't asked your doctor about the generic, that conversation is worth more than any Open Enrollment decision you'll make this year. If a brand name is medically necessary for you specifically, that's a decision for you and your doctor — but for most people on statins, the generic performs identically at a fraction of the cost, and I've seen the CMS formulary data confirm that nearly every 2026 Part D plan places rosuvastatin somewhere on its generic tiers.
This is the kind of analysis Pelandri runs for you automatically — cross-referencing your actual drug list against every plan's formulary tier, deductible design, and coinsurance structure, so you're not reconstructing this spreadsheet by hand every October.
Why "affordability" as a talking point won't fix your bill
This fall, healthcare affordability is showing up everywhere in the midterm election coverage — KFF Health News journalists have been making the media rounds discussing measles vaccination rates, food recalls, and the Affordable Care Act in the same breath as the November elections. In California's 22nd Congressional District, one of the most competitive House races in the country, voters are telling reporters that healthcare costs are their top issue, and they want to hear concrete plans from both the incumbent and his challenger before they decide.
Meanwhile, MedPAC — the independent commission that advises Congress on Medicare payment policy — just released its analytic agenda for the 2026-2027 meeting cycle, with public meetings running through next year examining plan payment methodology and program design questions that touch Part D's structure. That's valuable, serious work. It's also work that unfolds over a two-year meeting cycle, with policy changes that, if they happen at all, would show up in future plan years.
None of that helps you with the bill due at the pharmacy counter next month. Your formulary tier placement isn't decided by Congress or by MedPAC's research agenda — it's decided by each individual plan's Pharmacy & Therapeutics committee, and it gets re-filed with CMS every single year. The plan that put rosuvastatin on Tier 1 last year could move it to Tier 2 for 2026. The only way to know is to check your specific drug list against this year's formulary files before your enrollment window closes, not to wait and see what a two-year federal advisory cycle produces.
What to actually do before Open Enrollment ends
- Pull your current formulary tier for every drug you take — not just the ones you assume are expensive. Cheap generics on the wrong deductible design can cost more than you think.
- Ask your doctor, in writing if needed, whether a generic equivalent exists for any brand-name drug on your list. The Crestor-to-rosuvastatin math above ($1,900+ in annual savings) is not an outlier; it's the norm for statins, ACE inhibitors, and PPIs.
- Run your full drug list, not just one drug, across every plan available in your ZIP code. A plan that's cheap for rosuvastatin might be expensive for your blood pressure medication or your blood thinner — you can see how that plays out with a different drug combination in Turning 65 in 2026: Eliquis, metformin, and atorvastatin.
- Check whether you'd hit the $2,000 catastrophic cap on any given plan. If you will, prioritize premium. If you won't, prioritize per-drug tier placement and deductible design.
You can model every one of these steps for your specific drug list, dosage, and ZIP code at Pelandri — the same drug-by-drug, dollar-by-dollar comparison I used to do with a spreadsheet and a phone at the Area Agency on Aging, just faster, and built on actual CMS formulary and plan design data instead of guesswork. Open Enrollment is seven weeks long. Congress's next Part D conversation is scheduled over the next two years. Only one of those timelines is yours to control.
Sources
- With Midterms Looming, Journalists Consider Measles, Food Recalls, and Obamacare — KFF Medicare
- In Toss-Up House District, Voters Crave Leadership To Fix Broken Healthcare — KFF Medicare
- MedPAC’s analytic agenda for the 2026-2027 meeting cycle — MedPAC
- Presentations by MedPAC staff at the 2026 AcademyHealth Annual Research Meeting and the 2026 Annual Conference of the American Society of Health Economists — MedPAC
- Presentations by MedPAC staff at the 2025 AcademyHealth Annual Research Meeting — MedPAC