About Advantage Insurance Benefits:
Medicare Part D: Understanding Your Prescription Drug Coverage
Why Your Drug Costs Can Change From Year to Year
One of the most common surprises Medicare beneficiaries face is a prescription cost that's higher than expected — not because their medication changed, but because their plan did. Carriers are permitted to revise their formularies each year. A drug covered at Tier 2 this year may move to Tier 4 next year, or be removed from the formulary entirely.
This is why reviewing your Part D coverage annually isn't optional — it's essential. The plan that worked well for you last year may not be the most cost-effective option going forward. Our team reviews prescription coverage as part of every annual Medicare plan review we conduct, specifically to catch these changes before they affect your wallet.
Medicare Part D is the prescription drug benefit available to anyone enrolled in Medicare. It's offered through private insurance carriers approved by Medicare — either as a standalone Prescription Drug Plan (PDP) that pairs with Original Medicare, or bundled into a Medicare Advantage plan that already includes drug coverage.
Each Part D plan covers a list of approved medications called a formulary. Formularies are organized into tiers, and the tier your medication falls into determines how much you'll pay at the pharmacy. Here's how tiers typically work:
- Tier 1: Preferred generics — lowest cost-sharing
- Tier 2: Non-preferred generics — slightly higher cost
- Tier 3: Preferred brand-name drugs — moderate cost-sharing
- Tier 4: Non-preferred brand-name drugs — higher cost-sharing
- Tier 5: Specialty medications — highest cost-sharing, often a percentage of the drug's total cost
Not every drug is covered by every plan, and formularies vary from carrier to carrier. Checking whether your specific medications are covered — and at what tier — is one of the most important steps in choosing a Part D plan.
What Medicare Part D Actually Covers
Enrollment: When You Can Sign Up for Part D
Enrolling at the right time helps you avoid a late enrollment penalty that stays with you permanently. Here are the key enrollment windows:
- Initial Enrollment Period (IEP): The seven-month window surrounding your 65th birthday. Enrolling during this period avoids any late penalties.
- Annual Enrollment Period (AEP): October 15 through December 7 each year. This is when you can switch, drop, or add Part D coverage, with changes effective January 1.
- Special Enrollment Periods (SEPs): Available in specific circumstances, such as losing employer drug coverage or moving to a new service area.
If you delay enrolling in Part D without having creditable drug coverage from another source — such as an employer or union plan — Medicare may charge a late enrollment penalty. That penalty is calculated as a percentage of the national base premium and is added to your monthly Part D premium for as long as you have Medicare drug coverage.
Income-Related Part D Premium Adjustments (IRMAA)
Most people pay the standard premium for their Part D plan, but higher-income beneficiaries may pay more. This additional amount is called the Income-Related Monthly Adjustment Amount, or IRMAA. It's determined by the Social Security Administration based on your reported income from two years prior.
For 2024, IRMAA applies to individuals with income above $103,000 and married couples filing jointly with income above $206,000. The surcharge is paid directly to Medicare, separate from your plan premium. If your income has decreased significantly since the reference year — due to retirement, loss of a spouse, or other qualifying life events — you may be able to request a reconsideration from Social Security.
What Clients Say
Common Questions About Medicare Part D
How do I know if my medications are covered under Medicare Part D?
Each plan publishes a formulary — a list of covered drugs — that you can search by medication name. Because formularies differ between plans, it's worth comparing several options side by side. We do this as part of our plan review process, checking your specific medications against available plans to identify the best fit.Each plan publishes a formulary — a list of covered drugs — that you can search by medication name. Because formularies differ between plans, it's worth comparing several options side by side. We do this as part of our plan review process, checking your specific medications against available plans to identify the best fit.When can I enroll in a Medicare drug plan?
Your first opportunity is during your Initial Enrollment Period around your 65th birthday. After that, the Annual Enrollment Period from October 15 to December 7 is the main window each year. Special Enrollment Periods are available if you experience certain qualifying events, such as losing creditable drug coverage from an employer.Your first opportunity is during your Initial Enrollment Period around your 65th birthday. After that, the Annual Enrollment Period from October 15 to December 7 is the main window each year. Special Enrollment Periods are available if you experience certain qualifying events, such as losing creditable drug coverage from an employer.What happens if my drug isn't on my plan's formulary?
You have a few options. Your doctor may be able to request an exception or prior authorization from the plan. You could also switch plans during an eligible enrollment period to one that does cover your medication. In some cases, a therapeutically similar alternative that is covered may work just as well — your doctor can advise on that.You have a few options. Your doctor may be able to request an exception or prior authorization from the plan. You could also switch plans during an eligible enrollment period to one that does cover your medication. In some cases, a therapeutically similar alternative that is covered may work just as well — your doctor can advise on that.Is there a penalty for not enrolling in Part D when I first become eligible?
Yes, if you go 63 or more consecutive days without creditable prescription drug coverage after your Initial Enrollment Period ends, Medicare may assess a late enrollment penalty. This penalty is added to your monthly premium for as long as you have Part D coverage, so enrolling on time — or maintaining creditable coverage — matters.Yes, if you go 63 or more consecutive days without creditable prescription drug coverage after your Initial Enrollment Period ends, Medicare may assess a late enrollment penalty. This penalty is added to your monthly premium for as long as you have Part D coverage, so enrolling on time — or maintaining creditable coverage — matters.Can I switch my Part D plan every year?
Yes. During the Annual Enrollment Period each fall, you can switch to a different Part D plan, drop standalone drug coverage, or add it if you don't currently have it. Because formularies and premiums change each year, reviewing your options annually is one of the most practical ways to manage prescription costs over time.Yes. During the Annual Enrollment Period each fall, you can switch to a different Part D plan, drop standalone drug coverage, or add it if you don't currently have it. Because formularies and premiums change each year, reviewing your options annually is one of the most practical ways to manage prescription costs over time.
Getting the Right Drug Coverage Starts With a Conversation
Prescription drug coverage is one of the most personal parts of Medicare — what works for a neighbor or a family member may not work for you. With more than 22 years of Medicare experience, Shirley and our team take the time to understand your specific medications, your preferred pharmacies, and your budget before recommending any plan. We represent eight Medicare-approved carriers, which means we can compare real options rather than steering you toward a single solution.
If you're enrolling for the first time, switching plans, or simply not sure whether your current coverage still makes sense, we're here to help you work through it.