Medicare Part D has a standard level of coverage, but prescription drug coverage through MA depends on the plan you choose. You can use the Medicare Plan Finder to search for plans that cover specific medications. Most plans have their own list of drugs, called a formulary, and divide them into “tiers,” from low copayments to high copayments. If a formulary doesn’t include your specific drug and there are no alternatives available, it’s possible to ask for an exception.