After you have spent a certain amount of money for covered drugs, you have to pay all costs for your drugs while you are in the [Donut Hole or] “gap.” This amount doesn’t include your plan’s monthly premium, that you must continue to pay even while you are in the coverage gap. The coverage gap is sometimes called the “donut hole,”
Some Medicare drug plans offer a discount during the coverage gap.
*Note: if you get "extra help" paying your drug costs, you won’t have a coverage gap. However, you will have to pay a small copayment or coinsurance amount.
(source: Medicare.gov)
*Please note that this only applies to drugs that are on the plan's formulary (drug list).
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