The short answer
A drug can be on your plan's list and still carry a rule that stops the pharmacy filling it. The three rules are prior authorization, step therapy and quantity limits. One request, called a formulary exception, removes any of the three, and the clock on it waits on your prescriber.
Covered does not always mean you can collect it today. Something sits on top of the coverage, it has a name, and which name it is decides everything that follows.
Which rule is on my prescription?
Medicare plans may use some, all or none of a small set of rules on the drugs you take. Three of them stop a prescription at the counter, and they stop it for different reasons.
Here is what separates them.
| The rule | What your plan wants | Which page |
|---|---|---|
| Prior authorization | Approval before it covers the drug | Prior authorization |
| Step therapy | You to try a cheaper drug first | Step therapy |
| Quantity limits | To cap how much it covers at once | Named here only |
Prior authorization means the plan wants to say yes before it pays. You or your prescriber has to get that approval first, against requirements the plan sets itself.
Step therapy is a type of prior authorization. It asks you to try a certain less expensive drug on the plan's list first, one proven effective for most people with your condition, before you move up a step.
Quantity limits cap how much of a drug the plan covers over a period. Medicare's own example is a plan covering 30 tablets a month.
One thing may soften the first weeks of new coverage. When your drug coverage begins, you may get a transition fill: a one-time 30-day supply of a drug you have been taking that your plan either does not cover or requires prior authorization or step therapy for.
That fill buys time and settles nothing. Everything on this page is still true while you hold it.
Why will my plan not cover my drug?
There is a reason people expect, and a reason almost nobody knows about, and the second one changes what your prescriber has to write.
The expected reason is cost. These rules sit in the group Medicare calls plan rules, alongside medication safety checks, and plans use them to manage what they spend.
The second reason has nothing to do with money. Some drugs are covered only for particular diagnoses, and a plan will use prior authorization to check which one applies to you.
That changes the question. Your plan may not be asking whether you need medicine at all. It may be asking whether your diagnosis is one this drug is covered for, and the prior authorization article sets out what that means for what your prescriber has to write.
How do I get a rule removed?
All three of these rules are removed by the same request, and it is filed under a name that mentions none of them.
A formulary exception is the request used to get a drug covered that is not on your plan's list. It is also the request used to have a rule waived on a drug that is on the list, including step therapy, prior authorization and a quantity limit.
One request type, three different rules, and the reader who knows that stops looking for three separate processes.
One fact about the timing decides whether a wait is reasonable, and it catches almost everybody. The deadline does not run from the day you send the request in. It runs from the day your plan has the statement your prescriber writes.
What your prescriber has to say is different for each of these rules, and getting that wrong is how a request fails. Each page below carries only its own.
What this means for you
A covered drug can still carry a rule that stops the pharmacy filling it today. Three rules do that: prior authorization, step therapy and quantity limits.
The reason may not be money. A plan may also use prior authorization when a drug is covered for some conditions and not others.
One request removes any of them. A formulary exception is the request that waives this kind of rule, and its name says nothing about the rule it removes.
The deadline on that request does not run from the day you send it. It runs from the day your plan has your prescriber's statement, which is the step you cannot take yourself.
For approval before coverage, read this publication's article on Part D prior authorization. For being made to try a cheaper drug first, read the article on step therapy. For the request itself, who may file it and what happens if it is refused, read the article on how to request a drug exception.
FAQ
Is my drug not covered if it has one of these rules?
No, and this is the distinction the whole cluster turns on. A drug can be fully on your plan's list of covered drugs and still carry prior authorization, step therapy or a quantity limit. Being covered and being available to you today are two separate states.
What the rule does is add a condition before the plan pays, not remove the drug from the list. Prior authorization means approval is needed first. Step therapy means a cheaper drug has to be tried first. A quantity limit means the plan caps how much it covers over a period.
In each case the drug stays on the list, and in each case there is a documented request that removes the condition.
Which of these three rules do I have?
Your plan tells you, and the phrasing at the pharmacy is often the clue. Approval needed before the plan will cover it is prior authorization. Being told to try a different, less expensive drug first is step therapy, which Medicare describes as a type of prior authorization rather than a separate thing.
Being told the plan covers only a certain amount over a period is a quantity limit, and Medicare's own example is a plan covering 30 tablets of a drug per month. If more than one applies, they apply separately.
Your plan's list of covered drugs is where the rules attached to your specific drug are written down.
Do I need a different request for each rule?
No, and this is the single most useful thing on this page. A formulary exception is the request used to get a Part D drug covered that is not on your plan's list, and it is also the request used to have a utilization management requirement waived on a drug that is on the list.
CMS names step therapy, prior authorization and a quantity limit as examples of exactly that kind of requirement. So one request type covers being refused a drug, being made to try another first, and being made to ask permission.
What changes between them is not the form; it is what your prescriber has to state, and that differs for each.
How long does a decision take?
Once your plan has your prescriber's supporting statement, it must give written notice of its decision within 72 hours for a standard request, or 24 hours for an expedited one. The condition at the front of that sentence is the part worth reading twice.
CMS states that for requests involving exceptions, the adjudication timeframes do not begin until the plan receives the supporting statement from the prescriber. So a request filed a week ago may not be overdue at all, because the deadline has not started counting.
The article on requesting a drug exception carries the full clock, including payment requests and appeals.
What if my request is refused?
The refusal letter is also the instruction sheet. If your plan's coverage determination is unfavourable, the decision itself contains the information you need to file a request for redetermination, which is the first of five levels of appeal.
You have 65 calendar days from the date of the notice to file it, and that is the date printed on the letter rather than the day it arrived. You are not the only person who can act: you, your prescriber, or your representative may appeal.
The three articles under this page each carry the appeal route for their own rule, and the exception article carries it in full.
Can I get my medicine while I wait?
Possibly, if this is the start of your drug coverage. Medicare states that when your drug coverage begins you may get a transition fill, which is a one-time 30-day supply of a drug you have been taking that your plan either does not cover or requires prior authorization or step therapy for.
Read that as a bridge rather than a solution. It does not pause the request or extend any deadline, and the request still has to be made and decided on its own timetable.
Outside that opening period, what you can get while waiting is a question for your plan and your pharmacy rather than something Medicare publishes a general rule about.
