Not necessarily. Each plan has its own list of covered drugs, called a formulary, that includes both brand-name and generic drugs. Many plans have “tiers” of drugs, which determine how much you will pay for each drug. In addition, plans have coverage rules that limit what they will cover. You should examine all of these features of the plans.

With some exceptions, plan formularies must include at least two Part D drugs (not including the generic alternative to the brand drug) in each category and class of covered Part D drugs.

Coverage rules are used by the plans to steer beneficiaries toward lower-cost or safer drugs, and collectively they are known as “utilization management tools.” There are a number of techniques that a plan may sometimes use for certain expensive or high-risk drugs:

• A requirement to contact the plan to obtain prior authorization before a prescription is filled. Most often, you must ask your doctor to contact the plan.

• A requirement to try a lower-cost drug before a more expensive one is approved for coverage (a “step therapy” requirement).

• A limit on the quantity of drugs that can be dispensed at one time (or “quantity limit”). Frequently, this is less than a month’s supply. CMS requires the plans to post their utilization management rules on their websites by mid-November. It is valuable to check which rules will apply to the drugs you depend on.

Also, be aware that under certain circumstances, plans are allowed to change the drugs on their formulary, as well as their prices throughout the year. With some exceptions, if a plan decides to remove a drug from its formulary, move it to a more expensive tier or add utilization management requirements, it must continue providing the drug at the same cost-sharing level for the remainder of the plan year to those enrollees who were taking the medication at the time of the change.

Plans are required to provide beneficiaries currently taking a prescription with a 60-day notice of the formulary change. All other enrollees who may be prescribed the drug in the future would be subject to the new formulary and drug prices. These enrollees will not receive individual notice of the plan changes, but will be subject to the coverage limits and prices listed on the plan website.

Plans may replace brand-name drugs on their formularies with new generic drugs at any time. Plans are required to provide enrollees who are taking the brand-name drug at that time with a written notice at least 60 days before the change. If you receive such a notice, you should talk to your doctor to see if you can take the generic drug or need to stay on the brand-name version. If you need to take the brand-name drug instead of the generic drug, you or your doctor should request an exception to the formulary. Every plan must have a process in place for you to request an exception to the formulary limits when your plan does not cover a drug, requires trying another drug first or places a limit on the drug prescribed.

When you first enroll in a plan, you are entitled to coverage for a 30-day supply of any Part D drug you are currently taking.

Plans must cover this supply even if the drugs you need are not on the formulary, and they may not apply step therapy—requirements to try a lower-cost drug before a more expensive one is approved.