Part D is Medicare's prescription drug coverage. You get it either as a standalone plan alongside Original Medicare and a Medigap policy, or bundled inside a Medicare Advantage plan. Either way it is run by private insurers, and every plan publishes its own formulary.
The 2026 numbers
- $2,100 out-of-pocket cap. Once your own spending on covered drugs reaches $2,100 in a calendar year, you pay nothing more for covered drugs that year.
- $38.99 national base beneficiary premium. Not what you pay — it is the figure used to calculate the late-enrolment penalty.
- Medicare Prescription Payment Plan. You can now spread your out-of-pocket drug costs across the year in monthly instalments rather than absorbing them when they land.
The cap is genuinely new territory. Before it, a single specialty drug could run up unlimited out-of-pocket costs. It also means you can now put a firm ceiling on your worst-case year, which makes comparing plans far more concrete.
The penalty is permanent
Go 63 days or more without creditable drug coverage after your Initial Enrolment Period and Medicare adds a penalty to your Part D premium: 1% of the national base premium for every month you went without, recalculated each year as that base figure changes.
The word people underestimate is permanent. It does not expire, and it follows you from plan to plan for as long as you have Part D. A cheap drug plan you barely use is almost always less expensive than the penalty.
Formularies decide the cost, not premiums
Two plans with near-identical premiums can differ by thousands of dollars a year depending on whether your specific medications are on their list and at what tier. This is why comparing on premium alone is close to useless.
Bring your actual medication list — names and doses. Running it against the available plans takes about twenty minutes and it is the only comparison that means anything.
Pharmacies in Arizona
In Phoenix and Tucson, pharmacy access is rarely the constraint. Across the rest of the state it can be decisive. A plan with excellent pricing and no preferred pharmacy within 60 miles of you is a good plan for somebody else.
Two things worth checking if you live outside the metros — in Kingman, Lake Havasu City, Yuma, Sedona or the rural counties:
- Which local pharmacy is preferred, not merely in network. The price gap between those two tiers is often substantial.
- How the mail-order benefit works. For maintenance medications, 90-day mail order is frequently cheaper and more reliable than driving.
Extra Help
Extra Help, also called the Low-Income Subsidy, sharply reduces Part D premiums, deductibles and copays — and it removes the late-enrolment penalty. If you qualify for AHCCCS or a Medicare Savings Program you get it automatically. Many people who would qualify never apply because they assume they earn too much.
Common questions
What happens after I hit the $2,100 cap?
You pay nothing for covered prescriptions for the rest of the calendar year. The cap resets each January. Only your own out-of-pocket spending on covered drugs counts toward it — your monthly premium does not.
Do I need Part D if I take no medications?
Usually yes, and this is the most common expensive mistake we see. The late-enrolment penalty is permanent and grows the longer you wait. A low-cost plan now is nearly always cheaper than the penalty later, and it protects you if you are prescribed something expensive unexpectedly.
What is the Medicare Prescription Payment Plan?
It lets you spread your out-of-pocket Part D costs across the calendar year in monthly instalments instead of paying them at the pharmacy counter as they occur. It does not reduce what you owe overall — it changes the timing, which helps if an expensive drug would otherwise land in one month.
My drug is not on my plan's formulary. What now?
You can request an exception with your prescriber's support, ask about a covered alternative, or change plans at the next opportunity. Formularies change every January, which is why re-checking your drug list each autumn matters even if you are happy with your plan.
