Part D in one sentence

Medicare Part D is prescription drug coverage. Original Medicare, meaning Part A and Part B together, does not cover most of the medications you pick up at a pharmacy and take at home, and Part D is the piece that does. You can get it two ways: as a stand-alone Part D plan added to Original Medicare, often alongside a Medicare Supplement policy, or built into a Medicare Advantage plan. Either way it is private coverage run under Medicare's rules, and it is bought plan by plan rather than as one national product.

The 2026 and 2027 limits, plainly

Two numbers shape what Part D can cost you, and both are set by Medicare rather than by any one plan:

  • The maximum deductible. No Part D plan may charge a deductible above $615 in 2026 or $700 in 2027. Plans may charge less, and some charge nothing at all on certain tiers.
  • The out-of-pocket cap. Once your own spending on covered drugs reaches $2,100 in 2026, you pay nothing more for covered drugs for the rest of that year. In 2027 the cap is $2,400.

That ceiling is the part worth sitting with. It means a year with one very expensive medication has a known worst case rather than an open-ended one. It is also why going without drug coverage to save a modest premium tends to look worse in hindsight than it did at the time.

What actually differs between plans

Part D plans are not interchangeable, and the differences are not mainly about the premium. Four things decide what a plan costs you in practice:

  • The formulary. Every plan publishes its own list of covered drugs. A medication on one plan's list may be absent from another's entirely.
  • Tiers. Covered drugs sit on tiers, and the tier decides your share. The same medication can sit on different tiers in two different plans, which changes what you pay at the counter even though nothing about your prescription changed.
  • Pharmacy network. Plans sort pharmacies into preferred and standard, and the difference shows up every time you fill. The pharmacy you have used for twenty years in Mount Juliet or Smyrna may be preferred under one plan and standard under another.
  • Coverage rules. Some drugs require prior authorization, step therapy or quantity limits. These are worth knowing about before you need the medication, not after.

We will not tell you one plan is better than another, because that depends entirely on the specific list of medications in your cabinet. What we will do is run your actual prescriptions and your actual pharmacy against the plans offered where you live, and show you the comparison.

Where you live changes what is offered

Medicare Advantage and Part D availability can vary by county and ZIP code. That is not a technicality in Middle Tennessee — it is the practical reason this page is about Tennessee rather than about Medicare in general. The set of plans offered in Davidson County is not automatically the set offered in Williamson, Sumner, Wilson or Rutherford, so the plan a friend recommends in Franklin may simply not be on your list in Hendersonville or Murfreesboro. Pharmacy networks follow the same logic: a chain that is preferred across Nashville may not have the same standing at the independent pharmacy you use in Lebanon or Gallatin. Our Nashville Medicare page covers how we work across the region.

Part D and the rest of your coverage

How you get Part D depends on the path you chose for the rest of Medicare:

  • If you pair Original Medicare with a Medicare Supplement (Medigap) policy, that policy does not include drug coverage. People on this path almost always add a stand-alone Part D plan, and the supplement and the drug plan are bought separately, sometimes from different companies.
  • If you choose a Medicare Advantage plan in Tennessee, drug coverage is usually built in. Usually is not always, so it is worth confirming rather than assuming, and the formulary still matters just as much.

Either way you keep paying your Part B premium, which is $202.90 a month in 2026. Higher earners pay more on both sides: once modified adjusted gross income passes $109,000 for one person or $218,000 for a couple filing jointly, the first income bracket adds $14.50 to Part D and $81.20 to Part B, bringing a first-bracket Part B premium to $284.10 a month in total.

If the cost is the problem

There is real help available, and it is under-used. Extra Help assists with prescription drug costs; for one person in 2026 it uses figures of $23,940 in income and $18,090 in resources. The Medicare Savings Programs help with Medicare premiums and use 2026 monthly income limits for one person of $1,330 for QMB, $1,596 for SLMB and $1,796 for QI, with a resource limit of $9,950. Nobody should tell you across a desk whether you fit those figures — it is checked against your real numbers. But it is worth checking, because people routinely assume they are over the line when they are not.

Skipping Part D has a lasting cost

If you go without Part D after you were first eligible and you do not have other creditable prescription drug coverage in its place, a surcharge can be added to your Part D premium — roughly 1% of the national base beneficiary premium, $38.99 in 2026, for each full month of the gap. It is triggered by a gap of 63 days or more, and it generally stays with you for as long as you have Part D. The way people avoid it is unglamorous: keep the annual notice your employer, union or VA coverage sends you saying whether the drug coverage counts. Our guide to the Medicare late enrollment penalty explains how the surcharge is built, and when you can enroll in Medicare in Tennessee lays out the windows for adding or changing a drug plan.

This comes up often for people who reached Medicare through disability. Tennessee has not expanded Medicaid, so the stretch before Medicare begins is frequently a stretch without reliable drug coverage, and whether those months counted is the first thing to untangle.

How The Jordan Insurance Agency helps

Bring the actual bottles, or a list with the doses. We run each medication against the plans offered in your county, check your pharmacy's standing under each one, and show you what the year looks like rather than what the premium looks like. We do it again every fall, because formularies and tiers are rewritten annually and a plan that fit you last year can quietly stop fitting.

The Jordan Insurance Agency is an independent, licensed insurance agency with a Tennessee office at 159 4th Avenue N, Suite 100, Nashville, TN 37219. You can reach us at (615) 558-6082, Monday through Friday, 8:00 AM to 4:00 PM Central. Because we are independent we represent multiple carriers rather than one, so we can lay your real options side by side instead of steering you toward a single company. A consultation with a licensed agent is free, and your premium is the same whether you enroll on your own or with our help.