Medicare Drug Plans: What They Cover and How They Work

When you’re on Medicare, a U.S. federal health insurance program for people 65 and older, and some younger people with disabilities. Also known as Original Medicare, it covers hospital stays and doctor visits—but it doesn’t cover most prescription drugs unless you add a Medicare Part D, a standalone prescription drug plan offered by private companies approved by Medicare. This is the part that helps you pay for pills you pick up at the pharmacy, from blood pressure meds to insulin and antidepressants.

Not all drugs are covered the same way. Each Medicare drug plan has its own list of approved medications, called a formulary. Some plans cover generic drugs first, others prioritize brand names. Costs change based on where you are in your coverage: initial coverage, the donut hole (that gap where you pay more out of pocket), and catastrophic coverage. You might pay a monthly premium, a deductible, and then coinsurance or a flat copay per prescription. Some plans have no premium but limit which pharmacies you can use. And yes, you can switch plans during open enrollment each fall—no penalty if you pick a better fit.

What’s not covered? Things like weight-loss drugs, fertility treatments, and most over-the-counter pain relievers. Some plans offer extra benefits like discounts on vision or hearing aids, but those vary by provider. You’ll also need to check if your specific pharmacy is in-network—some plans only give you the lowest price at CVS or Walgreens, not your local corner drugstore. And if you’re on low income, you might qualify for Extra Help, a federal program that cuts your Part D costs significantly.

People often think Medicare automatically includes drug coverage, but it doesn’t. Skipping Part D when you’re first eligible can mean a late enrollment penalty that sticks with you for life. That’s why so many people end up paying more than they need to. The real trick isn’t finding the cheapest plan—it’s finding the one that covers the exact medications you take, at a pharmacy you use, for a price you can afford each month.

Below, you’ll find real breakdowns of how these plans work, what hidden costs to watch for, and how people in different states actually use them. Whether you’re helping a parent compare options or deciding for yourself, these posts cut through the noise and show you exactly what matters.