Drug Usage Restrictions under Medicare Part D

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Do you often go to fill a drug prescription, only to be met with rules and restrictions? Are you confused with all the limits set on the drugs you are prescribed under Medicare Part D? Here we clarify the rules, conditions, and limitations that come with some medications under Part D.

Drug usage restrictions

The main restrictions include:

  • Quantity limits. Quantity limits are set for certain drugs for which it would be a safety hazard to take too much or too often. With quantity limits, a plan will only cover a certain amount of the medication in a set amount of time, for example 30 pills in 30 days. Any amount above that will not be covered. On your drug plan’s formulary, Q:6/28Days would mean the plan will only cover 6 pills per 28 days.
  • Prior authorization. For certain drugs which are either more costly, have great side effects, or can only be taken for a short amount of time, a plan may require prior authorization before covering the drug. In this case, your doctor or pharmacist must request authorization by the plan to verify the medical appropriateness of the drug.
  • Step therapy. In certain cases, a drug plan will require you to try various cheaper versions of the same class of drug you are prescribed before using the brand name drug. Step therapy is mainly for drugs that must be taken on a daily basis, such as medications for high cholesterol or high blood pressure.

Exceptions and appeals

You can ask your plan to cover your drug by requesting a formulary exception. There’s also the option of asking for a one-time temporary supply of medication called a transition fill. The transition fill is applicable if your medication is no longer covered or if there are usage management restrictions on it.

If your plan denies your requests, you can file an appeal to your Medicare Part D plan.

Be prepared: check your formulary

It’s important to know that these limitations are in place for certain drugs so that you can be prepared. The conditions won’t be in place for every drug. Also, take note that your drug plan’s formulary can change each year. With it, rules and restrictions can change.

Your plan should notify you each fall of any changes via its Annual Notice of Change and Evidence of Coverage documents.

Drug formulary abbreviations

Here are some abbreviations you may find on your drug plan’s formulary and what they mean (courtesy of Q1Medicare):

PA = Prior Authorization
PA-NS = Prior Authorization New Starts
PA-BvsD = Prior Authorization-BvsD Only (Part D vs. Part B Prior Authorization Only)
QL = Quantity Limits
ST = Step Therapy 
ST-NS = Step Therapy New Starts
LA = Limited Access
MS = Mail Service Available


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