There is a good explanation of the Medicare coverage gap in
Medicare and You 2009 (PDF, 5.9MB) from the U.S. Department of Health and Human Services (HHS) Centers for Medicare and Medicaid Services (CMS). I will try to summarize.
Medicare Part D covers prescription drugs. What's covered depends on the specific Medicare Prescription Drug Plan you choose. As a patient on Medicare, you pay a monthly premium, plus a share of the cost of each drug prescription. The amount you pay varies during the year, and that's what can make it confusing. The "donut hole" refers to a coverage gap that is in most Medicare drug plans.
Here's the way it generally works. Note that I'm speaking in general, not about a particular person or plan, and the dollar amounts are only examples since they differ from plan to plan.
1. If your plan includes an
annual deductible, then at the start of the year you pay for your own prescription drug costs until the deductible amount is reached. Example: If your deductible is $295, then you pay the first $295 of the year's drug costs. There are no surprises. You know you have to pay a few hundred dollars at the start of each year.
2. Once your deductible has been paid, Medicare helps pay for drugs. You pay only
coinsurance or
copayment amounts, until the total drug costs for the year have reached a certain total. Example: You pay only a small share of drug costs until the full cost of those drugs reaches $2700. So far in the year you've paid only hundreds of dollars, with Medicare paying for the rest of the first $2700.
3. After that limit, you are responsible for all prescription drug costs until you reach your
annual out-of-pocket total. You are now in the "coverage gap" or "donut hole", and it can be expensive. You pay in full for prescription drugs until your total payments for the year (i.e., your deductible amount plus your coinsurance and copayment amounts) reach some fixed maximum. Example: You pay for all drugs until the total you've spent for the year is $4350.
4. Beyond your out-of-pocket total, Medicare provides you with so-called
catastrophic coverage. You pay at most small coinsurance or copayment amounts, as in #2 above. Your share of a prescription might be $10 or less, so you aren't likely to spend much more for the year.
The CMS offers some tips on
Bridging the coverage gap (PDF, 176K)