Plain-English definitions for every Medicare term — from ABN to ZIP enrollment. No jargon, no confusion.
Showing 31 results for "Part D" — clear search
The period each year from October 15 through December 7 when Medicare beneficiaries can change their Medicare Advantage or Part D drug plans. Changes take effect January 1 of the following year.
Also known as: Fall Open Enrollment
A document that Medicare Advantage and Part D plans must send to enrollees by September 30 each year. It outlines any changes to the plan's costs, coverage, or service area that will take effect January 1.
Also known as: ANOC
A prescription drug sold under its trademarked name. Brand-name drugs are typically more expensive than generic alternatives and may be in a higher formulary tier, requiring a higher copay or coinsurance under Part D.
The phase of Medicare Part D drug coverage that begins after you and your plan have spent a certain total amount on covered drugs in a year. In this phase, your copays are significantly reduced. In 2025, out-of-pocket costs are capped at $2,000 annually.
A phase in Medicare Part D where you pay a higher share of your drug costs after your total drug spending reaches a certain amount. Sometimes called the "donut hole." In 2025, the coverage gap was effectively eliminated for most beneficiaries due to the Inflation Reduction Act.
Also known as: Donut Hole
The process of leaving a Medicare Advantage or Part D plan. You can only disenroll during specific enrollment periods, such as the Annual Enrollment Period or a Special Enrollment Period. When you disenroll from a Medicare Advantage plan, you return to Original Medicare.
A detailed description of what your Medicare Advantage or Part D plan covers, how much it costs, and how the plan works. Plans must send you an EOC each year by October 15.
Also known as: EOC
A federal program that helps people with limited income and resources pay Part D prescription drug costs, including premiums, deductibles, and copays. Also called the Low Income Subsidy (LIS).
Also known as: Low Income Subsidy, LIS
A list of prescription drugs covered by a Medicare Part D plan or Medicare Advantage plan with drug coverage. Drugs are organized into tiers, with each tier having a different cost. Plans can change their formularies annually.
Also known as: Drug list, Preferred drug list
A prescription drug that has the same active ingredients, dosage, and effectiveness as a brand-name drug but is sold at a lower price after the brand-name patent expires. Generic drugs are typically in lower Part D tiers with lower copays.
A set amount of time after a premium due date, typically extending into the following month or two, during which you can still pay a missed Medicare Advantage, Part D, or Medigap premium before losing coverage.
The point at which your total drug spending under Part D reaches a set threshold, after which you enter the coverage gap phase. This limit applies to the combined spending by you and your plan.
Also known as: ICL
An extra amount added to your Part B and Part D premiums if your income is above a certain threshold, based on the tax return from two years earlier. IRMAA is reassessed annually and can be appealed after certain life-changing events like retirement.
Also known as: IRMAA
A higher premium added permanently to your Part B or Part D premium if you don't sign up for coverage when you are first eligible and don't have other qualifying coverage. The Part B penalty is 10% for each full 12-month period you were eligible but didn't enroll. The Part D penalty is 1% of the national base premium per month.
Also known as: LEP
See Extra Help. A federal program that reduces Part D costs for people with limited income and resources, covering most premiums, deductibles, and copays.
Also known as: LIS, Extra Help
A Medicare Advantage plan that bundles medical coverage (Part A and B) together with prescription drug coverage (Part D) into a single plan.
Also known as: MA-PD
The formal name for Medicare Advantage. A type of Medicare coverage offered by private insurers that combines Part A, Part B, and usually Part D coverage into one plan.
Also known as: Medicare Advantage
Medicare prescription drug coverage. A voluntary program offered through private insurers to help pay for outpatient prescription drugs. Plans vary in which drugs they cover (formulary) and what you pay. You may owe a late enrollment penalty if you don't join when first eligible.
Also known as: Prescription drug coverage
For Medicare Advantage, the period from January 1–March 31 each year when enrolled MA beneficiaries can switch to a different MA plan or return to Original Medicare (with Part D if desired). Changes take effect the first of the following month.
Also known as: OEP, Medicare Advantage OEP
The amount you pay for your Medicare coverage, typically deducted monthly. Part A is premium-free for most people. Part B has a standard monthly premium (adjusted for income). Medicare Advantage and Part D plans have their own premiums in addition to Part B.
A stand-alone Medicare Part D plan that provides prescription drug coverage for people enrolled in Original Medicare. PDPs are separate from Medicare Advantage plans that already include drug coverage.
Also known as: PDP, Stand-alone Part D Plan
Approval that your Medicare Advantage or Part D plan may require before you receive certain services or medications. Without prior authorization, the plan may not cover the cost. Original Medicare rarely requires prior authorization.
Also known as: Preauthorization, Pre-approval
The geographic area where a Medicare Advantage or Part D plan is available and provides coverage. Plans may have different networks and costs in different parts of their service area. Moving outside a plan's service area may trigger a Special Enrollment Period.
The minimum level of coverage that Medicare Part D prescription drug plans must provide. Plans may offer enhanced coverage above this standard, but all must include at least the standard benefit.
A 1–5 star quality rating system that CMS uses to measure how well Medicare Advantage and Part D plans perform. Ratings are based on measures including member experience, customer service, and managing chronic conditions. Higher-rated plans may receive bonus payments.
Also known as: CMS Star Ratings, Quality ratings
A coverage requirement where you must try a less expensive drug first before your plan will cover a more expensive one. Commonly used in Medicare Advantage and Part D plans to control costs.
Also known as: Fail first policy
A standardized document that Medicare Advantage and Part D plans must provide that summarizes the plan's costs, covered benefits, and important rules. It is a shorter, easier-to-read version of the Evidence of Coverage.
A level in a Part D formulary that determines how much you pay for a drug. Most plans have 4–5 tiers. Generic drugs are typically in lower tiers with lower copays; brand-name and specialty drugs are in higher tiers with higher copays or coinsurance.
Also known as: Drug tier
The amount that counts toward moving you through Medicare Part D phases and into catastrophic coverage. TrOOP includes what you pay out of pocket for covered Part D drugs, plus certain payments made on your behalf.
Also known as: TrOOP
Processes used by Medicare Advantage and Part D plans to ensure services and drugs are medically appropriate and used efficiently. Includes prior authorization, step therapy, and quantity limits.
Also known as: UM, Utilization review
The process of using your ZIP code to find Medicare Advantage or Part D plans available in your area. Plan availability, provider networks, and premiums can vary significantly based on your geographic location.
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