I just joined a new Medicare drug plan and my medicine isn't on its list. Do I have to go without?

A federal rule says a Part D drug plan must have a transition process. It is for people whose drug is not on the plan's formulary [1]. It also covers drugs that are on the formulary but need prior authorization or step therapy [1]. The process applies to new enrollees after the yearly enrollment period and to people new to Medicare. It applies to people who switch plans after the year starts, and to current members when the formulary changes [1].

The plan must give you a temporary supply of the drug in the first 90 days under a new plan [1]. If you ask for a fill in that time, you get a one-time supply of at least a month. The exception is a prescription written for less [1]. The plan must send you a written notice within 3 business days after it fills the drug. It must also make reasonable efforts to tell your prescriber [1].

The rule also sets your cost. If you get Extra Help, the plan can't charge more than the set maximum copayment. If you don't, it must charge what it would charge for an approved formulary exception, or what it would charge once its rules are met [1]. For a longer fix, your prescriber can ask for an exception with a supporting statement. For a request for benefits, the plan must give its decision in writing within 24 hours if expedited, or 72 hours if standard [2]. The sources here do not say how your own plan runs this. "Don't know yet" for your plan.

Open the CFR rule in Source 1 and read paragraph (b)(3). Your plan's formulary and transition policy show the details - "Don't know yet" for your plan.