Medicare Part D prescription drug plan formularies in 2012 covered 96 percent of the drugs most used by people eligible for both full Medicare benefits and Medicaid – full benefit dual eligibles – according to the Department of Health and Human Services Office of Inspector General (OIG). That figure is essentially unchanged from 2011, the OIG’s report says.

The Affordable Care Act health reform law requires the OIG to publish an annual study on the extent to which prescription drug formularies – the list of covered drugs – used by Medicare Part D stand-alone Prescription Drug Plans (PDPs) and Medicare Advantage drug plans (MA-PDs) include Rx drugs most commonly used by the nation’s 7 million full-benefit dual eligibles.

Medicare drug plans may exclude drugs from formularies or may control drug use in an effort to contain costs, but they must meet certain criteria in doing so.  Each PDP and MA-PD drug formulary is reviewed by staff in the Centers for Medicare and Medicaid Services (CMS).  Generally, Part D plan formularies must cover at least two drugs in every theraputic class.  Under CMS rules, Part D formularies must also include all or substantially all drugs in six protected classes: immunosuppressant (for prophylaxis of organ transplant rejection), antidepressant, antipsychotic, anticonvulsant, antiretroviral, and antineoplastic drugs.

The OIG’s findings this year include:

  • The rate of Part D plan formularies’ inclusion of the most commonly used drugs by dual eligibles is high.
  • Part D plan formularies include 96 percent on average of the 191 most commonly used drugs by dual eligibles under Part D prescription drug coverage.
  • All Part D plan formularies include more than 60 percent of the commonly used drugs.
  • Plan formularies increased the share of drugs subject to utilization management tools from 2011 to 2012, with 24 percent subject in 2012 compared to 19 percent in 2011.

Medicare Part D drug coverage and formulary requirements are detailed in Chapter 6 of the CMS Medicare Prescription Drug Benefit Manual.