Glossary
Medicare Part D
Medicare's optional prescription drug coverage — almost always unnecessary if you have TRICARE For Life.
Also known as: Drug Plan, PDP, Prescription Drug Plan, Part D
Quick answer
Part D is voluntary outpatient prescription drug coverage offered by private insurers under contract with Medicare. It has its own monthly premium, deductible, and tiered formulary.
Why it matters
For retired military, Part D is usually a mistake. The TRICARE Pharmacy Program (administered by Express Scripts) is **creditable coverage** — meaning it's considered as good as or better than Part D. You do not need Part D, and signing up can disrupt your TRICARE pharmacy benefits.
When you'll encounter it
You'd encounter Part D when comparing standalone drug plans (PDPs) or when an MA plan bundles drug coverage (MAPD). On TFL, the only time you'd seriously consider Part D is if a specific MA-PD plan offers it as part of the package.
Impact on Medicare
Part D is administered by private plans, not Medicare directly. It has a coverage gap ('donut hole') structure that resets annually.
Impact on TRICARE For Life
TFL beneficiaries should generally NOT enroll in a standalone Part D plan. TRICARE Pharmacy already covers your prescriptions through MTF, home delivery, network, and non-network channels.
Impact on Medicare Advantage
Many MA plans for veterans are MA-PD (include Part D drug coverage). You can use both the MA plan's drug benefits and TRICARE Pharmacy without losing either.
VA Healthcare considerations
VA prescription coverage is also creditable for Part D purposes. If you fill most prescriptions through the VA pharmacy, you remain protected from Part D late penalties — but you can still use TRICARE Pharmacy (Express Scripts) for non-VA prescriptions without conflict.
Military-specific context
TRICARE Pharmacy is one of the best drug benefits in the country: $0 generics at military pharmacies, low copays via Express Scripts home delivery, and a broad network. Adding a standalone Part D plan typically duplicates coverage you already have and may complicate pharmacy claim processing.
Common misconceptions
- "I have to enroll in Part D at 65 or pay a penalty." — Not if you have TRICARE. TRICARE Pharmacy is certified as creditable coverage, so no late-enrollment penalty applies.
Common mistakes to avoid
- Enrolling in a standalone Part D plan during AEP because a mailer made it sound mandatory.
- Assuming the prescription portion of an MA-PD plan replaces TRICARE Pharmacy — you can still use TRICARE Pharmacy alongside it.
- Letting a pharmacy bill Part D instead of TRICARE, leading to higher copays.
Real-world scenario: A retired Marine on TFL receives a Part D 'enrollment reminder' mailer near her 65th birthday.
She ignores it. Because TRICARE Pharmacy is certified creditable coverage, she owes no late penalty now or later. She continues filling generics through Express Scripts home delivery for $12 per 90-day supply — far less than any Part D plan would charge.
Questions people commonly ask
- Do I need a Part D drug plan if I have TRICARE?
- What is creditable drug coverage?
- Will I be penalized for not enrolling in Part D?
- Can I have TRICARE Pharmacy and a Medicare Advantage drug plan at the same time?
Continue learning
— suggested by the knowledge graph- What is Medicare? A complete overview for retired militaryA plain-English, handbook-grounded overview of the federal health insurance program for people 65 and older, written specifically for retired service members and their families.
- Understanding Original Medicare (Parts A & B) for veteransExactly what Part A and Part B cover, what they cost in 2026, and why both are required to keep TRICARE For Life.
- Creditable Drug CoveragePrescription drug coverage that CMS certifies is at least as good as standard Medicare Part D — including TRICARE Pharmacy and VA Pharmacy.
- Medicare Part D and TFLWhy TFL beneficiaries do not need (and usually should not enroll in) a standalone Medicare Part D plan.
- Appointment of RepresentativeA signed form (CMS-1696) that authorizes another person — family member, attorney, or advocate — to file or pursue a Medicare appeal on your behalf.
- Benefit Period (Part A)The Part A timeframe used to measure hospital deductibles and coinsurance — it resets after 60 days out of the hospital.
- Brand-Name DrugsFDA-approved drugs sold under a manufacturer's proprietary name — middle copay tier on the TRICARE formulary.
- Coverage DecisionA formal decision by a Medicare Advantage or Part D plan about whether — and how — it will cover a service, item, or prescription.
- Disability Medicare Eligibility (Under 65)Medicare eligibility before age 65 — automatic after 24 months of SSDI, immediately for ALS, and based on dialysis/transplant for ESRD.
- What is the 5-star Special Enrollment Period?A one-time-per-year chance (Dec 8 – Nov 30) to switch into a 5-star-rated Medicare Advantage or Part D plan in your area, outside the normal enrollment windows.
- I'm turning 65. What should I do first?About 3 months before your 65th birthday, sign up for Medicare Parts A and B at SSA.gov. TRICARE For Life activates automatically once both are effective and DEERS is current.
- Should I enroll in Medicare Part D?No, for almost every TFL beneficiary. TRICARE Pharmacy (Express Scripts) is creditable coverage and cheaper than most Part D plans. Adding Part D usually costs more without adding benefit.
- What is 'creditable coverage' for Part D?Drug coverage that's at least as good as standard Part D. TRICARE Pharmacy is creditable, so you can skip Part D without owing a late-enrollment penalty later.
- What is a pharmacy prior authorization?Some drugs (high-cost specialty, opioids, certain brand-names) require Express Scripts to approve before TRICARE will pay. Your doctor submits the request.
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Continue learning straight from the source. Every link below goes to an official government or DoD resource.
Last reviewed January 2026 against the 2026 Medicare & You and TRICARE For Life handbooks.