Medicare Part D Prescription Drug Plans are insurance plans offered by private insurance companies approved by Medicare to provide coverage for prescription medications. Part D plans are designed to help Medicare beneficiaries afford the costs of prescription drugs, which can be a significant expense for many individuals.

Key features of Medicare Part D Prescription Drug Plans include:

1. Coverage for Prescription Drugs: Part D plans provide coverage for a wide range of prescription medications, including brand-name drugs, generic drugs, and specialty drugs. Covered drugs are listed in the plan's formulary, which is a list of drugs that the plan covers.

2. Monthly Premiums: Medicare Part D plans typically have a monthly premium that varies depending on the plan's coverage, formulary, and the insurance company offering the plan. Premiums can vary widely, so it's essential to compare plans to find one that fits your budget.

3. Deductibles and Cost-Sharing: Part D plans may have an annual deductible that you must pay out-of-pocket before the plan starts covering prescription costs. After meeting the deductible, you'll typically pay a copayment or coinsurance for each prescription filled, and the plan covers the remaining costs up to a certain limit.

4. Coverage Gap (Donut Hole): In the past, there was a coverage gap in Medicare Part D plans known as the "donut hole." While in the coverage gap, beneficiaries paid a higher percentage of the drug costs until they reached catastrophic coverage. However, the Affordable Care Act has been closing this gap, and by 2020, beneficiaries pay a lower percentage of the costs during the coverage gap until they reach catastrophic coverage.

5. Formulary Changes: Part D plans can change their formularies, which may affect the coverage of specific drugs. It's important to review your plan's formulary annually during the open enrollment period and make changes if needed to ensure your medications are covered.

6. Network Pharmacies: Part D plans have networks of pharmacies where you can fill your prescriptions. Some plans may offer discounts or lower copayments for using preferred pharmacies within their network.

7. Extra Help: Low-income beneficiaries may qualify for Extra Help, a program that helps pay for Part D premiums, deductibles, and drug costs. Eligibility for Extra Help is based on income and resources.

Typical candidates for Medicare Part D Prescription Drug Plans include:

• Medicare beneficiaries who need prescription drug coverage in addition to their Original Medicare (Part A and Part B) benefits.

• Individuals enrolled in Medicare Advantage plans (Part C) that do not include prescription drug coverage and want to add this coverage separately.

• Those who take prescription medications regularly and want financial assistance with their drug costs.

To enroll in a Medicare Part D Prescription Drug Plan, you must be enrolled in Medicare Part A and/or Part B and live in the plan's service area. It's important to compare different Part D plans based on their coverage, premiums, formularies, and network pharmacies to choose a plan that best meets your prescription drug needs and budget.