How Part D works

Part D is optional outpatient prescription coverage sold by private plans. If you have Original Medicare, you typically add a standalone PDP. Many Medicare Advantage plans include Part D. Covered drugs, pharmacies, tiers, prior authorization, and costs vary by plan.

Creditable coverage and penalties

If you go 63 days or more without creditable prescription coverage after you are eligible, you may face a lifetime late enrollment penalty. Employer, VA, or other coverage may be creditable — confirm with the plan sponsor.

The 2026 drug benefit

Federal law has changed how Part D cost-sharing works in recent years, including an annual out-of-pocket cap for covered Part D drugs. The details of any specific plan still depend on its formulary and pharmacy network. Confirm current rules on Medicare.gov.

Basic and enhanced drug plans

Some stand-alone drug plans add coverage beyond the standard Part D benefit. The California list shows which 2026 plans are basic and which are enhanced.

Review without oversharing

My Medicare Checkup asks only about the general level of prescription use. It does not request medication names, dosages, or other protected health information. A licensed agent can review specific drugs later in a compliant conversation if you choose to share them.

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For the other pages on this topic, open the Lowering Medicare costs guide.

2026 figures