Medicare Part D open enrollment runs from October 15 through December 7 every year. This is the window when Medicare beneficiaries can change their prescription drug plan, switching plans, joining a plan for the first time, or making no change and continuing with their current coverage.
The consequence of ignoring this window: paying more than necessary for the same medications for the next full year.
Why Your Plan Changes Even When You Do Nothing
This is the most important thing to understand. Your Part D plan is not static. Every year, insurance companies can change their drug formularies (the list of covered medications), tier placements, copayment amounts, and prior authorization requirements. A medication that was Tier 2 (preferred generic) in your plan last year may move to Tier 3 (non preferred) or come off the formulary entirely.
CMS sends beneficiaries an Annual Notice of Change (ANOC) in late September each year. This document tells you what is changing in your plan for the upcoming year. Most people throw it away without reading it.
The pharmacist's recommendation: read the ANOC before October 15. If your medications are staying at the same tier and cost sharing, your plan is probably fine. If any of your regular medications have moved or been removed, the open enrollment window is your opportunity to fix that.
Key Terms You Need to Know
Premium: The monthly amount you pay for Part D coverage, regardless of whether you use any prescriptions that month.
Deductible: The amount you pay out of pocket before your Part D coverage begins paying. Plans can have a $0 deductible or up to the CMS maximum (which adjusts annually).
Copay vs. coinsurance: Copays are fixed dollar amounts per prescription. Coinsurance is a percentage of the drug cost. For expensive brand name medications, coinsurance plans can result in much higher out of pocket costs than expected.
Formulary: The plan's list of covered drugs. Not every drug is covered on every plan. Formularies are divided into tiers, generic drugs on Tier 1 have the lowest copays; specialty drugs on Tier 5 have the highest.
Donut hole (coverage gap): Historically, Medicare Part D had a coverage gap. The Inflation Reduction Act of 2022 dramatically changed the landscape, and starting in 2025, there is a $2,000 cap on out of pocket drug spending for Medicare beneficiaries. This is a significant change that reduces the financial burden of the donut hole for many patients.
How to Compare Plans
The Medicare Plan Finder at medicare.gov/plan compare is the official tool. To use it effectively:
- Have your Medicare ID number ready
- Enter your zip code (available plans vary by county)
- Enter each of your current prescription medications and doses
- Review the estimated annual cost results, this tool accounts for your specific drug list, formulary placement, and cost sharing for each plan
Beyond the Plan Finder, consider:
- Network pharmacy: Does the plan have preferred pharmacies in your area, including your current pharmacy? Using a non preferred pharmacy can significantly increase copays.
- Mail order options: Most Part D plans offer lower copays for 90 day mail order supplies of maintenance medications. If you take daily medications, this is worth calculating.
- Star ratings: CMS rates Part D plans on a 1 to 5 star scale based on drug safety, member experience, and customer service. All other factors being equal, a 4 or 5 star plan is preferred.
What a Pharmacist Medication Therapy Management Review Does
Beneficiaries on multiple Part D medications are often eligible for a free Medication Therapy Management (MTM) program through their Part D plan. A pharmacist conducts a comprehensive medication review, checking for drug interactions, unnecessary medications, adherence issues, and whether less expensive therapeutic alternatives exist.
This service is often underused. Ask your pharmacist or Part D plan whether you qualify.
The Coverage Gap Explained Under New Rules
Starting in 2025, the $2,000 out of pocket cap fundamentally changes the Part D math. Once a Medicare beneficiary's out of pocket spending on Part D covered drugs reaches $2,000, they pay $0 for the rest of the plan year. This is a major change from previous years and means that beneficiaries on expensive specialty medications can now budget with a known ceiling.
Additionally, the Inflation Reduction Act allows Medicare to negotiate prices for certain high cost drugs. The first negotiated prices began taking effect in 2026, with more medications being added in subsequent years.
Special Enrollment Periods
If you miss the October 15 to December 7 window, you can still make changes if you qualify for a Special Enrollment Period (SEP) due to circumstances like:
- Moving out of your plan's service area
- Losing other drug coverage
- Qualifying for Extra Help (low income subsidy)
Outside of SEPs, changes take effect January 1 of the following year.
When to Talk to a Pharmacist
A Medicare medication review with a pharmacist is particularly valuable if:
- You are new to Medicare Part D and are choosing a plan for the first time
- You have had significant medication changes in the past year (new prescriptions, dose changes, stopped medications)
- Your current plan's ANOC shows cost increases or formulary changes for your medications
- You take multiple brand name or specialty medications
- You are interested in whether any of your medications have equivalent generics that could reduce your costs
Stop by or call Fairview Pharmacy, we are happy to help you review your Part D options during open enrollment.
This article is for general information only and is not a substitute for personalized medical advice. Before starting or changing any medication, including over the counter products and supplements, talk with your pharmacist or physician about your specific situation.