Medicare Part D now runs on three phases instead of four — deductible, initial coverage, and catastrophic. Once your out-of-pocket spending on covered drugs hits the annual cap, you pay $0 for the rest of the year. That cap is indexed and adjusted annually, so the exact dollar amount changes each year — but the structure itself is now permanent.
Why Medicare Part D Changed
Since 2006, Medicare beneficiaries have gotten prescription drug coverage through Part D, delivered by private plan sponsors under contract with Medicare. For years, policymakers worried about three things:
- No hard cap on out-of-pocket drug spending
- Rapidly rising Medicare spending on high-cost enrollees
- Weak incentives for Part D plans to control drug prices
The Inflation Reduction Act (IRA) addressed these issues directly, restructuring the Part D benefit and phasing in a true out-of-pocket cap.
The New 3-Phase Medicare Part D Structure
Medicare Part D used to have four phases: deductible, initial coverage, coverage gap (donut hole), and catastrophic coverage. The coverage gap has been eliminated. Today there are three phases.
1. Deductible Phase
You pay 100% of your drug costs until you meet your plan’s deductible. Not every plan charges the maximum allowed deductible — some set it lower, or waive it for certain drug tiers.
2. Initial Coverage Phase
After the deductible, you pay your plan’s standard copay or coinsurance (commonly around 25%) while your plan covers the rest, until your total out-of-pocket spending reaches the annual cap.
3. Catastrophic Coverage Phase
Once your out-of-pocket spending on covered drugs hits the annual cap, you pay $0 for covered prescriptions for the remainder of the year. This is the single biggest change in Part D’s history — previously, enrollees still owed a percentage of costs even after reaching catastrophic coverage.
The Out-of-Pocket Cap: How It Works
The out-of-pocket cap took effect for the first time at $2,000 and adjusts upward annually based on Part D spending growth. CMS announces the new cap amount, along with the maximum standard deductible, each year — typically in the third quarter, ahead of open enrollment.
What counts toward the cap:
- Your deductible
- Copays and coinsurance on covered drugs
- Amounts covered by Extra Help (Low-Income Subsidy)
What does not count toward the cap:
- Monthly premiums
- Costs for drugs not on your plan’s formulary
- Discount-program purchases (e.g., prescription discount cards) instead of using your plan
The cap applies whether you have a standalone Part D plan or a Medicare Advantage plan with built-in drug coverage.
The Medicare Prescription Payment Plan (Cost Smoothing)
Even with a hard cap, some enrollees could still face a large bill early in the year if they hit the cap quickly (for example, after one expensive prescription fill). To solve this, Medicare introduced the Medicare Prescription Payment Plan — sometimes called “M3P” or “smoothing.”
This optional program lets you:
- Spread your out-of-pocket drug costs into predictable monthly installments across the year
- Avoid large lump-sum payments at the pharmacy
- Opt in through your Part D or Medicare Advantage plan
Other Recent Medicare Part D Changes
- Drug price negotiation: Medicare can now negotiate directly with manufacturers on select high-spend drugs, and negotiated prices are being phased in, lowering costs for beneficiaries who take those medications.
- No more donut hole math: Because the coverage gap phase no longer exists, the old rules about brand-name vs. generic cost-sharing in that phase are obsolete.
- Annual updates: Expect the deductible cap and out-of-pocket cap to increase modestly each year, in line with CMS’s annual Part D parameter announcement.
What This Means for Beneficiaries
For most enrollees, the practical effect is simple: prescription costs are far more predictable, and there’s a firm ceiling on annual spending. Enrollees with high-cost specialty medications benefit the most, since they’re the ones most likely to reach the cap — and previously the most exposed to open-ended costs in the old catastrophic phase.
Frequently Asked Questions
Does Medicare Part D still have a coverage gap (“donut hole”)?
No. The coverage gap has been eliminated. Part D now has three phases: deductible, initial coverage, and catastrophic coverage.
Is there a cap on Medicare Part D out-of-pocket costs?
Yes. Once your out-of-pocket spending on covered drugs reaches the annual cap, you pay $0 for covered prescriptions for the rest of the year. The cap amount adjusts annually.
What counts toward the Medicare Part D out-of-pocket cap?
Your deductible, copays, and coinsurance for covered drugs count. Premiums, non-formulary drug costs, and discount-card purchases do not count.
What is the Medicare Prescription Payment Plan?
It’s an optional program that lets you spread your out-of-pocket Part D drug costs into monthly installments throughout the year instead of paying larger amounts upfront at the pharmacy.
Does the out-of-pocket cap apply to Medicare Advantage plans too?
Yes. The cap applies to any plan with Part D prescription drug coverage, including standalone Part D plans and Medicare Advantage plans with drug coverage built in.
Bottom Line
Medicare Part D changes in recent years have simplified the benefit and added real financial protection: no more donut hole, a hard annual spending cap, and a built-in option to smooth out costs over the year. Because the exact dollar figures adjust annually, it’s worth checking your plan’s current-year numbers each fall during open enrollment.
If you’d like help understanding how these Medicare Part D changes affect your specific drug coverage and retirement income plan, our advisors at The Art and Science of Successful Planning, based in Fort Myers, work with Florida retirees to build prescription and healthcare costs into a full retirement strategy.
