Part D Plan: What You Need to Know About Medicare Drug Coverage

When you’re on Medicare, a Part D plan, a prescription drug coverage program offered by private insurers approved by Medicare. Also known as Medicare drug plan, it’s the only way most beneficiaries get help paying for medications like insulin, blood pressure pills, or cholesterol drugs. Without one, you could pay full price—sometimes hundreds of dollars a month—for drugs you need just to stay healthy.

Not all Part D plans are the same. Each one has its own list of covered drugs, called a formulary, the official list of medications a plan will pay for. Some plans cover generics only. Others include brand names but charge more. And some have gaps—like the infamous donut hole—where you pay 100% until you hit a spending threshold. You also need to check if your pharmacy is in-network. A plan that covers your meds but only at a pharmacy 50 miles away isn’t helpful.

Your Medicare drug coverage, the benefit provided through Part D plans to help pay for outpatient prescription medications doesn’t just stop at price. It includes things like prior authorization, step therapy, and quantity limits. For example, your plan might require you to try a cheaper drug first before approving the one your doctor prescribed. Or limit you to 30 pills a month, even if you need 90. These rules can make a big difference in how easy—or frustrating—it is to get your meds.

People on fixed incomes, especially those taking multiple prescriptions for conditions like diabetes, heart disease, or arthritis, rely on Part D to avoid choosing between meds and groceries. The right plan can cut your monthly drug costs by half or more. But choosing one isn’t just about picking the lowest premium. You need to match the plan to your actual meds, your pharmacy, and your budget over the whole year—not just January.

Below, you’ll find real guides from people who’ve been there: how to avoid coverage gaps, how to get generic versions of expensive drugs, how to appeal a denial, and how to spot when your plan changes its formulary without telling you. These aren’t theory pieces. They’re step-by-step, no-fluff answers to the questions you actually ask when you’re holding a $400 pill bottle and wondering if you can afford it next month.