Part D costs typically include:

• A monthly premium.
  
  

• An annual deductible (the amount you pay before coverage starts)

Formulary and Tiers:

Each Part D plan has a formulary—a list of covered drugs. These drugs are organized into tiers, with lower-cost generic drugs in lower tiers and more expensive brand-name or specialty drugs in higher tiers. Your out-of-pocket costs depend on the tier of the drug you’re prescribed.

Late Enrollment Penalty:

If you don’t enroll in Part D when first eligible and lack other creditable drug coverage, you'll face a

late enrollment penalty, which is 1% of the national base premium ($34.70 in 2024) for each month you delayed, added to your premium permanently.