What does Medicare Part D cover?

Drug coverage comes from private plans

Original Medicare does not cover most prescriptions you fill at a pharmacy. Part D does. It is offered by private insurance companies approved by Medicare, in two ways: a stand-alone drug plan you add to Original Medicare (with or without a Medigap policy), or drug coverage built into a Medicare Advantage plan. Either way, what you pay depends on which drugs you take and which plan you choose. If you'd like us to check your prescriptions against the plans we offer, that's what we do.

How a plan decides what it covers

What you pay

A Part D plan can have a monthly premium, a yearly deductible, and a copay or coinsurance each time you fill a prescription. In 2026, once what you pay out of pocket for covered drugs reaches $2,100, you pay nothing more for covered Part D drugs for the rest of the year; your premium still applies. In 2027 that limit rises to $2,400. In 2026, covered insulin costs no more than $35 for a month's supply, and recommended adult vaccines, such as the shingles vaccine, cost nothing under Part D.

If your drug costs come in large amounts, the Medicare Prescription Payment Plan lets you spread your out-of-pocket drug costs across the calendar year: instead of paying the pharmacy, you get a monthly bill from your plan. It does not lower your total drug costs; it changes when you pay them.

What Part D does not cover

Drugs given to you in a hospital are usually covered under Part A, and many drugs given in a doctor's office, such as some infusions, are covered under Part B. If a drug you need is not on your plan's list, you or your prescriber can ask for an exception, which is the plan deciding to cover a drug that is not on its list.

Don't let a gap cost you later

If you go 63 days or more in a row without Part D or other drug coverage that counts as creditable after you first become eligible, you may owe a late enrollment penalty, added to your premium for as long as you have Part D. People with limited income and resources can get Extra Help to lower Part D costs; some qualify automatically, and others apply. For the dates you can join or switch, see when you can change Medicare plans; for how drug coverage fits each path, see Medicare Advantage vs Medigap.

Common questions

Last reviewed October 2026. Medicare rules, dates and dollar amounts can change each year; Medicare.gov has the official details.