Best Prescription Drug Plans for Seniors on Medicare

These are the most searched questions about Medicare prescription drug plans, answered plainly. Read these before making any enrollment decision.

• 1
  What is the best drug plan for seniors on Medicare? No single best plan — it depends entirely on your specific medications and ZIP code · Wellcare: lowest average premium ($8/mo) · Humana: best $0-premium availability · AARP MedicareRx: broadest formulary (5,600+ drugs) · Always compare at medicare.gov/plan-compare

  The honest answer is that “best Part D plan” is meaningless without knowing which drugs you take. Two seniors in the same ZIP code with different medications can have completely opposite plan rankings — Plan A might be ideal for one and cost hundreds more for the other. That said, certain carriers earn consistently strong marks from CMS and independent reviewers. Wellcare and Humana are rated best overall for 2026 by NerdWallet’s analysis, which weighted premiums, CMS star ratings, member satisfaction, and drug tier pricing. Wellcare’s average monthly premium is around $8 — well below the national average of $62. Humana offers $0-premium plans in more states than any competitor and has strong low out-of-pocket tier structures on generics. The AARP MedicareRx Preferred plan (administered by UnitedHealthcare) covers over 5,600 medications and has a $0 deductible on Tiers 1–3, making it worth the higher premium for seniors on multiple medications. Run all of these through Medicare.gov Plan Finder with your specific drug list before choosing.
• 2
  What is the $2,100 out-of-pocket cap for Part D? New in 2025–2026 via the Inflation Reduction Act · Once you spend $2,100 on covered Part D drugs in a calendar year (including your deductible), you pay $0 for covered prescriptions for the rest of the year · Replaces the old “donut hole”

  The coverage gap — commonly called the “donut hole” — was a stage in the old Part D structure where seniors temporarily lost most drug coverage and faced much higher out-of-pocket costs. The Inflation Reduction Act eliminated it. Starting in 2025 and continuing in 2026, there is now a straightforward out-of-pocket cap: once you spend $2,100 on covered Part D drugs in a calendar year (counting your deductible, co-pays, and coinsurance), every covered prescription for the rest of that year costs you nothing. The $2,100 cap includes your annual deductible — so a plan with a $615 deductible counts those dollars toward your cap as you pay them. For seniors on expensive brand-name drugs or specialty medications, this cap can represent thousands of dollars in protection. Insulin users with diabetes who hit the cap save especially dramatically for the remainder of the year.
• 3
  Is GoodRx better than Medicare Part D? For specific generic drugs at specific pharmacies: sometimes yes · For overall protection and brand-name drugs: usually no · Critical warning: using GoodRx for a prescription means it doesn’t count toward your $2,100 Part D out-of-pocket cap · Never cancel Part D for GoodRx alone

  GoodRx can offer lower prices than Part D on certain generic drugs at certain pharmacies — and for seniors on one or two common generics, it can genuinely cost less at the counter. However, the comparison breaks down on two fronts. First, GoodRx prices vary by pharmacy, drug, and day — there is no ceiling on what you’ll pay year to year. Second, and more critically: when you use GoodRx to purchase a prescription, that spending does not count toward your Medicare Part D $2,100 out-of-pocket cap. That means in a year where you develop a new health condition and suddenly need expensive medications, you have no Part D protection and will pay full out-of-pocket on all of them. Many seniors mistakenly believe they can save money by dropping Part D in favor of GoodRx for their current cheap generics — but doing so exposes them to catastrophic costs if their medication needs change, and triggers a permanent late enrollment penalty if they try to rejoin Part D later. Keep Part D even if GoodRx is cheaper for your current drugs. Use GoodRx as a comparison tool, not a replacement.
• 4
  What is the Part D late enrollment penalty — and how permanent is it? 1% of the national base premium ($38.99 in 2026) for every month you went without creditable drug coverage · Penalty is permanent and added to your monthly premium for life · Avoiding it by enrolling in even a $0-premium plan during initial eligibility is almost always the right move

  The Part D late enrollment penalty is one of Medicare’s most misunderstood and most painful surprises. If you don’t enroll in a Part D plan when you first become eligible for Medicare (or don’t have other creditable prescription drug coverage like an employer plan), Medicare adds 1% of that year’s national base beneficiary premium — $38.99 in 2026 — for every month you were without coverage. If you went 24 months without a Part D plan, your penalty is approximately 24% of $38.99, or roughly $9.36/month, added to your plan’s premium — forever. That’s over $112/year in permanent extra costs for simply not enrolling when you should have. The fix is simple: even if you currently take no medications, enroll in a low- or $0-premium Part D plan when you first become eligible. Wellcare and other carriers offer benchmark plans with very low premiums in most states. At $8–$15/month, it costs far less than any penalty that accumulates from delaying enrollment even one year.
• 5
  Is SilverScript a good Part D plan? Mixed in 2026 — SilverScript Choice (now under Aetna) has a 3-star CMS rating, higher-than-average premiums, and below-average member satisfaction · No $0-premium option available · Better alternatives exist in most states for most seniors

  SilverScript was once one of the most popular Part D plans nationally, but its 2026 positioning has weakened. Aetna now offers only one Part D option — SilverScript Choice — in 49 states, and it earned a 3-star CMS quality rating, which is average. Monthly premiums range from $14.70 to $116 depending on the region, with a weighted average around $70.56 — significantly above the national average of $62. Member satisfaction scores dropped year-over-year. The plan does have one structural advantage: a simplified pharmacy network where out-of-pocket costs are the same at all in-network pharmacies, which eliminates the preferred vs. standard pharmacy confusion common at other carriers. However, for most seniors in most states, Wellcare, Humana, and HealthSpring (formerly Cigna) offer comparable or better coverage at lower prices with higher member satisfaction scores. If you are currently on SilverScript, compare it against available alternatives during the next Annual Enrollment Period using Medicare.gov’s Plan Finder.
• 6
  Why is Medicare Plan G considered one of the best — and is it the same as Part D? Medicare Plan G is a Medigap supplement plan (covers Medicare A & B gaps, including deductibles and copays) — it is NOT prescription drug coverage · Part D is separate · Most seniors on Plan G still need a standalone Part D plan for medications · Plan G + Part D together is one of the most comprehensive coverage combinations available

  Medicare Plan G and Medicare Part D are completely different products that serve different purposes. Plan G is a Medigap (Medicare Supplement) policy that fills the cost gaps left by Original Medicare Parts A and B — it pays your Part A deductible ($1,676 in 2026), Part B coinsurance, hospital stays, and various other cost-sharing amounts. It does not cover prescription drugs. Part D is a separate standalone drug plan that specifically covers medications picked up at the pharmacy. Plan G is considered one of the most comprehensive Medigap plans because it covers nearly every out-of-pocket cost from Parts A and B except for the Part B deductible ($257 in 2026). Seniors with Plan G plus a Part D plan have some of the most complete Medicare coverage available — minimal surprises on the hospital and doctor side, plus drug coverage. If you have Plan G, you almost certainly still need a Part D plan unless you have other creditable drug coverage.
• 7
  How do drug formulary tiers work and why do they matter so much? Tier 1: generics (~$0–$5 copay) · Tier 2: preferred brand-name (~$10–$40) · Tier 3: non-preferred brand (~$50–$100) · Tier 4–5: specialty drugs (25–33% of drug cost, potentially hundreds per month) · A drug on Tier 1 at one plan can be Tier 3 at another — your total annual cost can differ by thousands

  Every Part D plan organizes its covered drugs into tiers, and the tier your specific medication lands on determines what you pay. Generic drugs (Tier 1 and 2) typically cost $0–$10 per prescription. Preferred brand-name drugs (Tier 3) run $30–$100. Non-preferred brand-name drugs (Tier 4) can cost $100 or more per fill. Specialty drugs (Tier 5) — which include many cancer, autoimmune, and biologics — are typically charged at 25–33% of the drug’s cost per month, which on a $5,000/month specialty drug means $1,250–$1,650 out of pocket per month until you hit the $2,100 cap. The same drug can sit on Tier 1 at one plan and Tier 4 at another. This is why the monthly premium alone tells you almost nothing about what a plan will actually cost you. A plan with a $45/month premium that keeps your blood thinner on Tier 1 will almost certainly cost less annually than an $8/month plan that lists it on Tier 3. Medicare.gov’s Plan Finder calculates your estimated total annual cost including premiums plus all drug costs for your specific medication list — use it every year during Open Enrollment.
• 8
  When can I change my Part D plan — and what happens if I miss the window? Annual Enrollment Period: Oct 15 – Dec 7 (new coverage starts Jan 1) · Open Enrollment Period: Jan 1 – Mar 31 (switch MA plans only, not standalone Part D) · Special Enrollment: within 63 days of losing creditable coverage · Miss the window: stuck until next AEP

  The Annual Enrollment Period (AEP) from October 15 to December 7 is the primary window to change your Part D plan. Any changes made during this period take effect January 1 of the following year. The Medicare Open Enrollment Period from January 1 to March 31 allows you to switch Medicare Advantage plans, but standalone Part D plan changes are generally not available during this window. Special Enrollment Periods exist for specific life events — the most common for seniors is the 63-day window after losing other creditable prescription drug coverage (such as when leaving an employer plan). If you miss AEP and don’t have a qualifying Special Enrollment Period event, you are locked into your current plan until the next AEP. This is why reviewing your coverage every fall is essential — plans change their formularies, their pharmacy networks, and their drug tier assignments annually, and a plan that was excellent for you last year may have moved your key medications to a more expensive tier.

The plans below represent the top-rated options based on CMS star ratings, independent analysis, and member satisfaction scores. Premiums, availability, and drug coverage vary by state and ZIP code. Always verify at medicare.gov/plan-compare before enrolling.

Free, unbiased Medicare counseling is available through SHIP (State Health Insurance Assistance Program) in every state. Use the buttons below to find local help, pharmacies, and Medicare offices near you.