Part D Prescription Drug Plan

A Part D Prescription Drug Plan adds drug coverage to Original Medicare (Parts A and B). If you are staying with Original Medicare rather than switching to Medicare Advantage, a standalone Part D plan is how you cover your prescription costs. You enroll in Part D separately, and it runs alongside your Medicare coverage.

Every Part D plan has a formulary — a list of covered drugs organized into tiers. Generic medications are usually in the lowest tiers with the lowest copays. Brand-name and specialty drugs are in higher tiers with higher costs. Before enrolling, run your current medications through the plan's formulary to confirm they're covered and check which tier they're in. Two plans with similar premiums can have dramatically different costs for the same medication.

The late enrollment penalty is worth understanding. If you don't enroll in Part D when you're first eligible and go more than 63 consecutive days without creditable drug coverage, you'll pay a penalty added to your premium permanently — 1% of the national base premium for every month you delayed. If you have employer coverage that counts as creditable, you can delay without penalty. If you don't, enrolling even in a low-cost plan protects you from the penalty.

Part D plans in Utah, Ohio, and Pennsylvania vary widely in premium (typically $5–$80/month), deductible, and formulary. The Medicare Plan Finder at medicare.gov is the best tool for comparing them — enter your exact medications and it calculates your estimated annual total cost across all plans at your zip code. That number, not the premium alone, is the right way to compare Part D plans.