How do Part D formularies and drug tiers work?

Quick Answer

A formulary is a plan's list of covered drugs. Each drug on the list is placed in a tier, and higher tiers generally mean higher out-of-pocket costs for you.

Detailed Explanation

Every Medicare Part D plan, and every Medicare Advantage plan with drug coverage, has a formulary. Think of it as the plan's approved drug list. If your medication is on the formulary, the plan helps pay for it. If it isn't, you're generally paying full price unless you get an exception approved.Drugs on the formulary are sorted into tiers, typically numbered one through five or six depending on the plan. Tier one is usually generic drugs with the lowest copay. Tier two is often preferred brand-name drugs. Tier three is non-preferred brands. Higher tiers typically include specialty drugs, which are high-cost medications often used for complex conditions, and they can come with significant cost-sharing.The tier a drug sits on directly affects what you pay at the pharmacy. Two plans might both cover the same medication but place it on different tiers, meaning your cost could vary quite a bit between them.Formularies can change during the year, and plans are required to notify you of significant changes. They also vary from plan to plan and year to year, so what was covered last year may be on a different tier or off the formulary entirely this year. Before enrolling or staying in a plan, it's worth checking where your specific medications land using the plan's drug lookup tool or by calling the plan directly.

How This Applies in Utah

What This Means For You

For you, this means your specific prescriptions should be the starting point when comparing Part D or Medicare Advantage plans, not the premium, because a lower premium sometimes comes with much higher drug costs.

Disclaimer

‍How Resting Sycamore Advisors Uses CMS Data

Our Commitment to Reliable Medicare Information

At Resting Sycamore Advisors, we work to provide accurate, current, and trustworthy information about Medicare Advantage, Medicare Part D, and Special Needs Plans.

To do that, we use data published by the Centers for Medicare & Medicaid Services (CMS), which is the official source for Medicare plan and enrollment information.

CMS Data Sources We Rely On

Our Medicare plan pages and comparison tools are powered by CMS datasets, including:

  • Medicare Advantage and Part D Landscape Files for annual plan availability and benefit details
  • Plan Benefits Package (PBP) Files for detailed benefit and coverage information
  • Part C and Part D Performance Data for quality ratings and plan performance measures
  • Monthly Enrollment Data for enrollment counts by contract, plan, state, and county

When possible, we link to the original CMS resources so you can review the source material directly.

How Often We Update Our Data

We follow the CMS release schedule and update our website as new data becomes available.

Annual Plan Year Updates (September)

We load new plan year Landscape and PBP files before the Medicare Annual Enrollment Period (October 15 through December 7). We also monitor CMS.gov for updates or revisions and refresh our content when needed.

Mid-Year Updates

We update enrollment and performance data as CMS publishes revised files, which are typically released monthly or quarterly.

Ongoing Maintenance

We routinely monitor CMS announcements for corrections, reissued files, or other changes and update our pages accordingly.

Each plan page includes a Last Accessed date so visitors can see when the source information was most recently reviewed.

How We Prepare CMS Data for Our Website

CMS data can be difficult to read in raw form. To make it easier to use, we format and organize the data for clarity.

This includes:

  • Standardizing plan identifiers such as contract ID, plan ID, and segment
  • Normalizing terminology so common Medicare terms are presented consistently
  • Organizing plan information by state, county, and ZIP code to match how people shop for coverage

All data values come from CMS. We do not change the underlying values beyond formatting, organization, and presentation.

Version Tracking and Transparency

We keep internal records of the CMS dataset versions used on our site.

Major Version History

  • Current Version: CY2025 Medicare Advantage and Part D Landscape Files (v1.0, published October 2025)
  • Prior Version: None. Resting Sycamore Advisors first began publishing structured Medicare plan information in March 2025

If CMS issues corrected or revised files, we update our website to reflect the latest available version.

Important Limitations

Please keep the following in mind:

  • CMS is the official source of truth. For enrollment and coverage decisions, always confirm details with Medicare.gov or 1-800-MEDICARE.
  • Data timing can vary. Enrollment and performance updates may appear on our website a few weeks after CMS publishes changes.
  • Plan details can change. Plan availability, costs, and benefits may change. Always verify current details directly with the plan provider.

Need Help From Official Medicare Resources?

For personalized Medicare assistance, please use these official resources:

  • Medicare.gov Help Center — https://www.medicare.gov
  • 1-800-MEDICARE (1-800-633-4227) TTY: 1-877-486-2048
  • State Health Insurance Assistance Program (SHIP) — free local counseling for Medicare beneficiariesIf you want, I can also give you a shorter legal-style version for a footer or /disclaimer page summary.