If you're approaching 65, recently enrolled in Medicare, or helping a loved one navigate their coverage, one of the first questions you'll run into is: what does Medicare Part D cover? It's a simple question with a surprisingly detailed answer—and getting it wrong can mean unexpected bills at the pharmacy counter, uncovered prescriptions, or paying for a plan that doesn't actually match your needs.

Medicare Part D is the part of Medicare specifically designed to help cover the cost of outpatient prescription drugs. It's offered through private insurance companies—not directly by the government—and it's available either as a standalone plan that supplements Original Medicare or as part of a Medicare Advantage plan that bundles medical and drug coverage together. In 2026, roughly 53 million of the 67 million people enrolled in Medicare have some form of Part D drug coverage, making it one of the most widely used components of the entire Medicare program.

But here's the thing: Part D doesn't cover everything. There are entire categories of prescription drugs that are excluded by federal law, and individual plans can vary enormously in which specific medications they include on their formularies. In this comprehensive guide, we'll break down exactly what Medicare Part D covers in 2026, what it doesn't, how the new Inflation Reduction Act protections affect your wallet, and how to make sure you're in the right plan for your prescriptions. Whether you're in North Bellmore , Long Island , or anywhere across New York, MediHealth Options is here to help you understand every detail.

What Does Medicare Part D Cover? The Basics

At its core, Medicare Part D covers most outpatient prescription drugs—meaning medications your doctor prescribes that you pick up at a retail pharmacy, have delivered through a mail-order service, or fill at a preferred pharmacy in your plan's network. This includes brand-name medications, generic drugs, biological products, insulin, and most vaccines recommended by the Advisory Committee on Immunization Practices (ACIP), including the shingles vaccine, the flu shot, and COVID-19 vaccines.

Every Part D plan is required by CMS to cover a broad range of prescription drugs across all therapeutic categories. While individual plans have some flexibility in choosing exactly which drugs to include on their formulary (their list of covered medications), they must meet minimum federal standards. Specifically, each plan must cover at least two drugs in every drug category and class. And there are six "protected classes" where coverage requirements are even stricter—plans must cover substantially all drugs in these categories because missing even one could have life-threatening consequences for patients. Those six protected classes are: immunosuppressants (for organ transplant recipients), antiretrovirals (for HIV/AIDS), antidepressants, antipsychotics, anticonvulsants (for seizure disorders), and antineoplastics (cancer medications).

In practical terms, if you take medications for conditions like high blood pressure, diabetes, high cholesterol, heart disease, arthritis, depression, anxiety, asthma, COPD, osteoporosis, thyroid disorders, or infection, your Medicare prescription drug plan will almost certainly cover them—though the specific brand or generic version covered, and what you pay for it, varies by plan. That's why working with a knowledgeable Medicare broker to compare formularies is so important.

How Part D Organizes Drug Coverage: The Tier System Explained

Medicare Part D plans don't just list which drugs they cover—they organize those drugs into tiers that determine how much you'll pay out of pocket for each prescription. Understanding this tier system is essential because the same medication can sit on completely different tiers depending on which plan you choose, meaning your cost for the exact same drug could range from $5 to $50 or more.

Most Part D plans use a structure of three to five tiers. Tier 1 contains preferred generic drugs—these are the least expensive, often costing just a few dollars per prescription. Tier 2 typically includes non-preferred generics or preferred brand-name drugs at a moderate copay. Tier 3 holds non-preferred brand-name drugs with higher cost-sharing. Tier 4 is reserved for specialty drugs—typically high-cost medications for complex conditions like cancer, rheumatoid arthritis, or multiple sclerosis. Some plans add a Tier 5 for the most expensive specialty medications. The key takeaway: a drug on Tier 1 with one carrier could be on Tier 3 with another, costing you dramatically more each month for the same medication.

This is exactly why at MediHealth Options, we start every consultation by reviewing your complete medication list. We run each drug through available plans in your area to see exactly where it falls on each formulary and what your copay or coinsurance would be. It's the only way to get an accurate picture of what a plan will actually cost you—and it's a service we provide completely free of charge. If you're in East Meadow , Massapequa , or anywhere on Long Island, we're happy to sit down with you and walk through this process.

What Medicare Part D Does NOT Cover

This is where many beneficiaries get surprised. While Part D covers a wide range of prescription drugs, federal law specifically excludes several categories of medications from coverage. No Part D plan—regardless of the carrier—can cover these drugs, and paying out of pocket for them will not count toward your annual $2,100 out-of-pocket cap.

Weight-loss medications. Drugs prescribed solely for weight loss—including Wegovy, Ozempic (when used specifically for weight loss rather than diabetes), and Xenical—are excluded from Part D. Without coverage, patients can pay upward of $1,350 per month for Wegovy. However, it's important to note that some of these medications may be covered when prescribed for other approved conditions. For example, Ozempic is typically covered when prescribed for Type 2 diabetes management, and Wegovy may be covered when prescribed to reduce the risk of cardiovascular events in patients with obesity. A Medicare model to potentially expand GLP-1 coverage for obesity is being explored for 2027.

Erectile dysfunction medications. Drugs like Viagra, Cialis, and Levitra are entirely excluded from Part D coverage, regardless of the reason they're prescribed. This exclusion has been in place since Part D launched in 2006.

Cosmetic medications. Drugs prescribed solely for cosmetic purposes—such as hair loss treatments like finasteride and minoxidil, or anti-wrinkle treatments like Renova—are not covered. However, medications for skin conditions like psoriasis, acne, rosacea, or vitiligo are not considered cosmetic and are generally covered by Part D.

Over-the-counter medications. Even when your doctor writes a prescription for an over-the-counter product like Miralax, Claritin, or Tylenol, Part D won't cover it. However, if a higher-dose, prescription-only version of an OTC drug is prescribed, that specific formulation may be covered.

Prescription vitamins and minerals. Most prescription vitamins and mineral supplements are excluded, with the exception of prenatal vitamins and fluoride preparations.

Cough and cold medications. Prescription cough syrups and drugs used solely for the relief of cold or cough symptoms are generally excluded from Part D coverage.

Drugs not approved by the FDA. Medications that have not been approved by the U.S. Food and Drug Administration for sale in the United States are not eligible for Part D coverage.

If you take any medication that falls into these excluded categories, it's important to plan for those costs separately. The team at MediHealth Options can help you identify which of your prescriptions are covered versus excluded and explore alternative options or assistance programs that might help reduce your out-of-pocket costs.

Part D vs. Part B: Which Part of Medicare Covers Your Drug?

One of the most common points of confusion is the difference between drugs covered under Part D and drugs covered under Medicare Part B. The distinction matters because it affects where you get the drug, how much you pay, and which plan is doing the covering.

Part D covers outpatient prescription drugs—medications you pick up at a pharmacy and take on your own at home. This includes pills, capsules, inhalers, topical creams, eye drops, insulin pens, and most self-administered injections.

Part B covers drugs that are administered by a healthcare provider in a clinical setting—such as infusions given at a doctor's office or outpatient hospital, certain injectable medications, some cancer treatments, and immunosuppressive drugs administered in a facility. Part B also covers certain medical equipment and supplies related to drug administration.

The important thing to know is that if a drug is covered under Part B, it's not covered under Part D—and vice versa. Some medications, like certain cancer treatments, can be covered under either part depending on how and where they're administered. The $2,100 annual out-of-pocket cap for 2026 applies only to Part D drugs, not Part B drugs. If you're managing a complex condition that involves both types of medications, understanding this distinction is critical for budgeting your healthcare costs. Our advisors at MediHealth Options help clients sort through these nuances every day.

Major 2026 Changes That Affect What Part D Covers and Costs

The 2026 plan year brought some of the most significant changes to Medicare Part D since the program began in 2006. Thanks to the Inflation Reduction Act (IRA), several new protections are now in place that directly affect what you pay for covered medications.

The $2,100 annual out-of-pocket cap. This is the headline change for 2026. Once your total out-of-pocket spending on covered Part D drugs—including deductibles, copays, and coinsurance—reaches $2,100 in a calendar year, your plan covers 100% of your covered prescription costs for the rest of the year. The old "donut hole" or coverage gap has been fully eliminated. In 2022, the average Part D beneficiary's annual out-of-pocket costs were nearly $6,500, so this cap represents enormous savings for anyone with significant drug costs.

The $35 monthly insulin cap. All covered insulin products remain capped at $35 per month, regardless of the type or quantity of insulin you need. This protection, which began in 2023, has saved approximately 1.5 million Medicare enrollees hundreds of dollars annually. The cap applies even during the deductible phase—so you'll never pay more than $35 for a month's supply of insulin from day one of the plan year.

Free vaccines. All Part D-covered vaccines recommended by the Advisory Committee on Immunization Practices (ACIP) are now available at $0 cost to you. This includes the shingles vaccine (which previously cost many beneficiaries $200 or more out of pocket), the flu shot, COVID-19 vaccines, the RSV vaccine, and others.

Negotiated prices on 10 high-cost drugs. For the first time in Medicare history, CMS has negotiated lower prices on 10 of the most expensive Part D drugs: Eliquis (blood clots), Jardiance and Farxiga (diabetes/kidney disease), Xarelto (blood clots), Januvia (diabetes), Entresto (heart failure), Enbrel (rheumatoid arthritis), Imbruvica (cancer), Stelara (autoimmune conditions), and NovoLog/Fiasp (insulin). These negotiated prices represent discounts of 38% to 79% off previous list prices and are estimated to save beneficiaries $1.5 billion in 2026. All Part D plans are required to cover these drugs at the negotiated rates.

The Medicare Prescription Payment Plan. New for 2026, this optional program lets you spread your out-of-pocket prescription costs into predictable monthly installments throughout the year instead of paying large sums upfront in January and February. All Part D plans must offer this option, and there's no additional cost to participate. It doesn't lower your total costs, but it smooths them out—which can be a huge help if you take expensive medications and face a large deductible at the start of the year.

These protections apply regardless of which Medicare prescription drug plan you choose—but the underlying plan structure, formulary, and tier placements still vary widely. That's why comparing plans carefully remains essential.

How Formularies Work and Why They Matter

Every Part D plan has a formulary—a comprehensive list of the prescription drugs it covers. Think of it as the plan's menu. If your medication is on the formulary, the plan will share the cost with you according to its tier structure and your plan's cost-sharing rules. If your medication is not on the formulary, you'll generally need to pay 100% of the cost out of pocket—and that spending won't count toward your $2,100 annual cap.

Formularies are not static. Plans can update them throughout the year—adding new generics, removing brand-name drugs that now have biosimilar alternatives, changing tier placements, or adding new restrictions like prior authorization (where the plan must approve the drug before covering it), step therapy (where you must try a less expensive drug first), or quantity limits. Some of these changes can happen with relatively short notice, which is why reviewing your plan's formulary annually during the enrollment period is so critical.

For New York residents, the state's EPIC program (Elderly Pharmaceutical Insurance Coverage) provides additional secondary coverage that can help with Part D cost-sharing and even covers some Part D-excluded drugs like prescription vitamins and cough and cold preparations. If you're a Long Island senior enrolled in Part D, checking whether you qualify for EPIC could provide meaningful additional savings.

At MediHealth Options , we check every client's medications against the formulary of every available plan in their area. We don't just confirm that your drugs are covered—we verify the tier placement, check for restrictions like prior authorization or step therapy, and calculate what your actual out-of-pocket cost would be at your preferred pharmacy. It's the level of detail that separates a good plan choice from one that costs you hundreds of dollars more than it should.

What to Do If Your Medication Isn't Covered

Discovering that a medication you rely on isn't covered by your Part D plan can be stressful—but you have options. First, talk to your doctor about formulary alternatives. In many cases, a different medication in the same drug class can treat your condition just as effectively and may be on a lower tier of your plan's formulary. Generic alternatives are often available at a fraction of the cost of brand-name drugs.

Second, you or your prescriber can request a formulary exception from your plan. This is a formal request asking the plan to cover a non-formulary drug, waive a prior authorization or step therapy requirement, or move a drug to a lower cost-sharing tier. If your doctor can demonstrate that the alternatives on the formulary aren't appropriate for your medical situation, plans are required to review and respond to your request promptly. If the exception is denied, you have the right to file an appeal.

Third, explore patient assistance programs. Many pharmaceutical manufacturers offer programs that reduce or eliminate out-of-pocket costs for specific medications, particularly expensive specialty drugs. These programs have varying eligibility criteria, but they're worth investigating—especially for high-cost drugs that might otherwise be unaffordable.

And finally, if your current plan simply doesn't cover the medications you need, consider switching plans during the next Annual Enrollment Period (October 15 through December 7). Our team at MediHealth Options provides annual plan reviews specifically to catch these issues before they become problems. If your medications have changed, or if your plan's formulary has shifted, we'll identify a better-fitting plan and help you make the switch seamlessly.

Get Help Understanding Your Part D Coverage with MediHealth Options

Understanding what Medicare Part D covers—and what it doesn't—is one of the most important steps you can take to protect both your health and your budget. But you don't have to figure it out alone. At MediHealth Options, we've spent over 15 years helping Medicare beneficiaries across Long Island and the greater New York area navigate the complexities of prescription drug coverage with clarity, confidence, and zero pressure.

We work with all the major carriers— Wellcare , Humana , Aetna , UnitedHealthcare , Blue Cross Blue Shield , and more—so our recommendations are always based on what's best for your medications, your pharmacies, and your budget. Whether you need a standalone Part D plan to pair with a Medicare Supplement plan or want to explore Medicare Advantage options with built-in drug coverage, we'll walk you through every option and help you choose with confidence.

Book your free Medicare consultation today or call 631-236-3348 to speak directly with a licensed advisor. Whether you visit us at our North Bellmore office, meet over the phone, or schedule a home visit, we'll review your prescriptions, compare your plan options, and make sure you're getting the coverage you need at a cost you can afford. Because at MediHealth Options, it's simple: people first, people always.