Medicare and Prescription Drugs: What Is Covered and What Is Not?

Medicare covers prescription drugs, but not through a single unified benefit. Coverage is split between Part B (for drugs administered in a clinical setting) and Part D (for most outpatient medications you pick up at a pharmacy). Understanding which part applies to your situation -- and what each one costs -- is essential for managing your healthcare budget in 2026.

Medicare Part B Covers Some Prescription Drugs in Certain Circumstances

Medicare Part B covers drugs that are administered by a healthcare provider in a clinical setting, not drugs you self-administer at home. Part B drug coverage is built into your standard Part B benefit -- there is no separate enrollment required.

Common examples of drugs covered under Part B include:

• Chemotherapy drugs administered in a doctor's office or outpatient hospital setting

• Injectable drugs given during a covered medical procedure (such as certain biologics and immunosuppressants)

• Vaccines including the flu shot, pneumococcal vaccine, hepatitis B vaccine (for at-risk individuals), and COVID-19 vaccines

• Drugs used with durable medical equipment such as nebulizer medications and insulin used with an insulin pump

• Certain oral cancer drugs that have the same active ingredient as an injectable drug covered by Part B

• Osteoporosis drugs injected by a home health nurse after a fracture in certain circumstances

For Part B drugs, you typically pay 20% coinsurance after meeting your Part B deductible ($283 in 2026), and there is no out-of-pocket maximum under Original Medicare unless you have a Medicare Supplement plan. Learn more about why some drugs are covered under Part B instead of Part D.

Medicare Part D Covers Most Outpatient Prescription Drugs

Medicare Part D is the prescription drug benefit that covers most medications you pick up at a pharmacy. Part D plans are offered by private insurance companies approved by Medicare. You can add a standalone Part D plan to Original Medicare, or get drug coverage bundled into a Medicare Advantage plan.

2026 Part D Cost Structure

How Part D Formularies Work

Every Part D plan maintains a formulary -- a list of covered drugs organized into tiers. Lower tiers (generics and preferred drugs) have lower cost-sharing; higher tiers (brand-name and specialty drugs) cost more. Plans must cover at least two drugs in each therapeutic category, and they must cover all drugs in six protected classes: antidepressants, antipsychotics, anticonvulsants, antiretrovirals, immunosuppressants, and antineoplastics.

Formularies can change from year to year. If your plan drops a drug you take or moves it to a higher tier, you will receive notice and may be able to request an exception. Learn more about how Part D formularies work.

What Medicare Does Not Cover

Even with both Part B and Part D, there are categories of drugs that Medicare does not cover under any circumstances:

• Over-the-counter (OTC) drugs such as aspirin, antacids, and cold medicines (even if prescribed by a doctor)

• Weight loss drugs prescribed solely for weight management (though some plans may cover GLP-1 drugs for diabetes or heart disease indications)

• Fertility drugs and medications used for cosmetic purposes

• Drugs used to treat erectile dysfunction (though some Medicare Advantage plans may offer this as a supplemental benefit)

• Vitamins and supplements unless used as part of a covered treatment (such as certain prenatal vitamins)

• Drugs not approved by the FDA or drugs used off-label for a non-covered indication

• Drugs covered under Part A or Part B -- these cannot also be billed to Part D

What if My Drug Is Not Covered?

If your medication is not on your plan's formulary, you have several options:

1. Request a formulary exception. Ask your doctor to submit a coverage determination request to your plan. If the plan denies it, you can appeal.

2. Ask about a therapeutic alternative. Your plan may cover a similar drug in the same class at a lower tier. Your doctor can prescribe the covered alternative.

3. Switch plans during the Annual Enrollment Period. Each fall (October 15 to December 7), you can switch to a Part D plan that covers your specific medications.

4. Use the Medicare Prescription Payment Plan. If your drug is covered but expensive, this program lets you spread your out-of-pocket costs in monthly installments rather than paying large amounts at once.

5. Apply for Extra Help (Low-Income Subsidy). If you qualify, Extra Help significantly reduces your premiums, deductibles, and copays.

The Role of Medicare Advantage Plans

Most Medicare Advantage (Part C) plans include prescription drug coverage (MAPD plans). These plans follow the same basic Part D rules -- including the $2,000 out-of-pocket cap -- but each plan has its own formulary, cost-sharing structure, and pharmacy network. Some Medicare Advantage plans also offer supplemental benefits that standalone Part D plans do not, such as coverage for certain OTC items or reduced cost-sharing on specific drug tiers.

If you have a Medicare Advantage plan without drug coverage (PFFS or MSA plans), you can enroll in a standalone Part D plan. However, if your Medicare Advantage plan includes drug coverage, you generally cannot also enroll in a separate Part D plan. Read more about MAPD vs. standalone Part D.

Help Is Available: Extra Help (Low-Income Subsidy)

Extra Help (also called the Low-Income Subsidy, or LIS) is a federal program that helps people with limited income and resources pay for Part D costs. In 2025, the income limit was approximately $23,475 for individuals and $31,725 for married couples, with resource limits of $17,600 and $35,130 respectively. (2026 limits are typically announced mid-year.)

If you qualify for Extra Help, you may pay little or nothing for your monthly Part D premium, have no deductible, and pay only small copays for each prescription. You can apply for Extra Help through Social Security at ssa.gov or by calling 1-800-772-1213. Learn more about the Medicare Extra Help program.

Frequently Asked Questions