Definition. Medicare Part D is prescription drug coverage offered by private plans, either as a stand-alone drug plan with Original Medicare or built into a Medicare Advantage plan. In 2026, what you pay for covered drugs is capped at $2,100 a year. Going without creditable drug coverage can mean a late enrollment penalty.
What it means
Part D covers most outpatient prescription drugs. Each plan has its own formulary (list of covered drugs), pharmacy network and costs, within Medicare's rules. Key 2026 rules:
- Out-of-pocket cap: $2,100 for covered drugs; after that, you pay nothing more for covered drugs that year.
- Deductible: no more than $615; some plans have a lower one or none.
- Insulin: no more than $35 for a month's supply of each covered insulin, with no deductible.
- Vaccines: no cost-sharing for adult vaccines the CDC's advisory committee recommends, such as shingles.
- Medicare Prescription Payment Plan: lets you spread your drug costs into monthly payments over the year.
- Extra Help: lowers premiums, deductibles and copays for people with limited income and resources.
In Oregon
Oregon and Washington form Part D region 30. For 2027, CMS lists 8 stand-alone Part D plans in Oregon from 4 companies; Medicare Advantage plans with drug coverage vary by county. The plan with the lowest premium isn't always the lowest total cost, so check your own drugs against each plan's formulary with Medicare's Plan Finder or see plans for your ZIP code on PlanMatch. If you have OHP and Medicare, OHP doesn't pay for drugs Part D covers, so you need Part D coverage. PERS Health Insurance Program Medicare plans include Part D, so PHIP members shouldn't add a separate drug plan.
Sources
- Medicare.gov — Costs for Medicare drug coverage
- Medicare.gov — What Medicare drug coverage (Part D) covers
- CMS — Part D public use file record layout (PDP regions) (PDF)
- Oregon Health Authority — OHP and Medicare
- Oregon PERS — About the PERS Health Insurance Program
Frequently asked questions
Is Part D required?
No, but if you go 63 days or more in a row without Part D or other creditable drug coverage after your Initial Enrollment Period, you'll generally owe a late enrollment penalty for as long as you have Part D.
Is there still a donut hole in 2026?
No. The coverage gap ended in 2025. Part D now has a yearly cap on what you pay for covered drugs: $2,100 in 2026. Once you reach it, you pay nothing more for covered drugs that year.
How many stand-alone Part D plans are in Oregon?
CMS's 2027 data list 8 stand-alone Part D plans in Oregon from 4 companies. Oregon and Washington share Part D region 30, so the same stand-alone plans are offered statewide.
Medicare in your Oregon county
Plans, local agents and help, county by county: Multnomah · Washington · Clackamas · Lane · Marion · Jackson · Deschutes · Linn · Douglas · Yamhill · Benton · Polk · Josephine · Umatilla · Klamath · Coos · Columbia · Lincoln · Clatsop · Malheur · All 36 counties →
