Medicare · updated 2026-06-28

Medicare Part D prescription-cost guide

How Medicare Part D phases, formularies, and the 2026 out-of-pocket cap affect prescription costs.

What matters most

Check whether the drug is covered, what tier it is on, whether prior authorization or step therapy applies, and whether a preferred pharmacy lowers your copay.

The Inflation Reduction Act changed Part D out-of-pocket exposure; compare annual plan costs, not just monthly premiums.

Cash price vs Part D

Sometimes a cash coupon looks cheaper than Part D at the counter, but it may not count toward deductible or out-of-pocket totals. Ask the pharmacist to compare both.

Sources and next steps