Glossary
Medical Necessity
A documented clinical justification that a non-formulary or restricted drug is required — allowing TRICARE to cover it at a lower tier.
Also known as: med necessity, MN review
Quick answer
Medical Necessity is a clinical review process where the prescriber documents that a non-formulary or restricted drug is medically required (typically because formulary alternatives failed, are contraindicated, or are clinically inappropriate). If approved, the drug is dispensed at the brand-name formulary copay rather than the higher non-formulary tier.
Why it matters
A Medical Necessity approval can reduce monthly OOP from hundreds (non-formulary cash price) to a standard formulary copay. It's the most important tool for drugs TRICARE does not place on the preferred list.
When you'll encounter it
Any prescription that flags as non-formulary or denies for PA based on formulary status.
Impact on Medicare
None — Medicare does not see TRICARE Pharmacy adjudications.
Impact on TRICARE For Life
Approval moves the drug from non-formulary to formulary brand pricing across MTF, Home Delivery, and retail network.
Impact on Medicare Advantage
MA-PD plans have a separate process called a 'formulary exception.' Not interchangeable with TRICARE Medical Necessity.
Military-specific context
Forms are at militaryrx.express-scripts.com/prior-authorization. Decisions return in 72 hours (24 for urgent). Approvals typically last 12 months and require renewal.
Common misconceptions
- "Only the patient can request Medical Necessity." — The prescriber files it — the patient just asks them to start the process.
Common mistakes to avoid
- Accepting a non-formulary copay long-term without asking for Medical Necessity.
- Forgetting to renew the approval before it expires after 12 months.
Real-world scenario: A retiree's neurologist prescribes a non-formulary migraine biologic.
First fill prices at hundreds out-of-pocket. Patient calls the neurologist, who files Medical Necessity citing prior triptan failures. Approved in 48 hours; subsequent fills at the brand formulary copay.
What should I do?
- 1Ask the prescriber to file Medical Necessity any time a drug is flagged non-formulary.
- 2Track approval expiration dates — most last 12 months.
- 3Keep copies of approval letters; useful if you ever need to appeal.
Continue learning
— suggested by the knowledge graph- Prescription drug coverage under TRICARE For LifeWhy TFL beneficiaries use TRICARE Pharmacy (Express Scripts), not Medicare Part D — and how the four pharmacy options compare.
- How Medicare and TRICARE For Life claims are paidThe mechanics of the Medicare-to-TFL crossover system — what providers do, what WPS does, and what to do if a claim gets stuck.
- What is TRICARE For Life? The complete guide for retired militaryThe Medicare-wraparound benefit you earned through service — what it covers, who qualifies, what it costs, and how it activates.
- How Medicare and TRICARE For Life work togetherThe exact mechanics of who pays first, who pays second, and what you owe — for every common care scenario.
- Non-Network PharmacyA civilian pharmacy that is NOT contracted with Express Scripts — highest cost and usually requires you to pay up front and file a claim.
- Overseas Pharmacy ClaimsHow TFL beneficiaries fill prescriptions outside the US — usually pay up front and file for reimbursement.
- Brand-Name DrugsFDA-approved drugs sold under a manufacturer's proprietary name — middle copay tier on the TRICARE formulary.
- Creditable Drug CoveragePrescription drug coverage that CMS certifies is at least as good as standard Medicare Part D — including TRICARE Pharmacy and VA Pharmacy.
- Express ScriptsThe pharmacy benefit manager that administers the TRICARE Pharmacy Program, including TFL home-delivery and retail-network prescriptions.
- Generic DrugsChemically identical, FDA-approved equivalents of brand-name drugs — the lowest copay tier under TRICARE Pharmacy.
- Medicare Part D and TFLWhy TFL beneficiaries do not need (and usually should not enroll in) a standalone Medicare Part D plan.
- What if my drug isn't on the TRICARE formulary?Non-formulary drugs cost more. Your doctor can request a medical-necessity exception so it's covered at the formulary copay.
- TFL denied a claim. How do I appeal?WPS handles TFL appeals. File a written reconsideration with WPS within 90 days of the denial. Include the Medicare EOB, the WPS denial, and any supporting medical records.
- Does TFL pay for durable medical equipment (DME)?Yes. Medicare covers Part B DME (wheelchairs, CPAPs, walkers) at 80% from a Medicare-enrolled supplier; TFL pays the remaining 20%.
- Who pays first, Medicare or TRICARE For Life?Medicare pays first for any service it covers. TFL pays second. The claim usually crosses over automatically — you should never pay out of pocket up front.
- 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.
Related glossary terms
Related Official Resources
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.