CJ Karrer
Writer · Reviewed by Richard ChanUpdated Jun 12, 2026
1 min read
Medicare Part D plans are standalone prescription drug plans offered by private insurance companies approved by Medicare to help cover the cost of medications.
Each Part D plan has a formulary, which is a tiered list of covered drugs that dictates the copayment or coinsurance amounts the beneficiary will pay.
Beneficiaries who delay enrolling in a Part D plan when they are first eligible and go without creditable drug coverage may face a permanent late enrollment penalty.
Managing the rising costs of necessary prescriptions is a frustrating reality for many, but a Medicare Private Drug Plan—often referred to as a standalone Part D plan—can offer a much-needed buffer. Sold by Medicare-approved private insurers, these plans act as a financial shield against the high prices of both brand-name and generic medications. Knowing exactly how these drug plans are structured allows you to make informed choices, ensuring your pharmacy runs don't derail your monthly budget. Here is a closer look at how Part D coverage works, what it includes, and how it can help you maintain your health and your savings.