Buprenorphine access in Medicare Part D varies nearly sixfold across state lines. Vermont's rate of 5.34 claims per 1,000 total Part D claims in 2016 dwarfed New Jersey's 0.86. That gap is the real story inside a decade of collapsing opioid prescribing.

Fentanyl's Decade-Long Retreat

Prescribed fentanyl in Medicare Part D fell from 2,782,815 claims in 2013 to 722,609 in 2023, a drop of 74% over ten years. The number of prescribers writing those claims fell from 64,924 to 23,622 over the same period. Beneficiaries receiving fentanyl dropped from 314,606 to 50,931.

Oxycodone followed a similar arc, though with a delay. Claims peaked at 8,264,935 in 2016 before declining to 7,240,220 by 2021. The cost story is even sharper: total oxycodone spending fell from $1,041,935,417 in 2013 to $561,804,356 in 2021, even as claim counts stayed above 7 million. Cost per claim dropped from $162.40 to $77.59 over that period, reflecting a shift toward generics and formulary pressure.

For patients, this compression in prescribing has two faces. Some of it reflects genuine clinical progress in managing chronic pain without opioids. But for the roughly 2 million Medicare beneficiaries who were receiving opioids at the peak, a portion of that decline represents access cut off rather than need resolved.

The Prescriber Landscape for Buprenorphine Doesn't Match the Need

As opioid prescribing contracted, buprenorphine, the medication-assisted treatment backbone for opioid use disorder, should have expanded to meet rising addiction caseloads. The specialty breakdown from 2016 tells a different story.

Addiction Medicine specialists, the providers most trained to manage opioid use disorder, accounted for only 14,100 buprenorphine claims from 102 prescribers. Physical Medicine and Rehabilitation providers wrote 22,915 claims from 463 prescribers. Emergency Medicine contributed 22,814 claims from 208 prescribers.

That means the specialty explicitly defined by addiction care was writing fewer buprenorphine claims than physiatrists or emergency physicians. The treatment infrastructure for opioid use disorder in Medicare was, at least in 2016, largely improvised from adjacent specialties rather than built around dedicated addiction medicine capacity. For a Medicare population with high rates of comorbidity and complex medication regimens, that matters: addiction medicine specialists are better positioned to manage interactions, adjust dosing, and coordinate with behavioral health.

A Sixfold Gap in State Access

Vermont's rate of 5.34 per 1,000 was more than six times New Jersey's 0.86. New England dominated the top of the list, with four of the five highest-access states clustered there. West Virginia, despite being at the center of the opioid crisis by almost every measure, came in at 1.67, well below the New England leaders.

The geographic concentration matters because Medicare beneficiaries don't choose where they live based on treatment access. A 65-year-old with opioid use disorder in New Jersey faces a fundamentally different treatment landscape than one in Vermont, not because their clinical needs differ, but because the prescribing infrastructure around them does. If that sixfold gap persisted or widened after 2016, a substantial share of Medicare's most vulnerable patients were effectively locked out of the treatment that the clinical evidence most strongly supports.

Fentanyl's cost per claim fell from $155.64 in 2013 to a low of $101.03 in 2020, then partially recovered to $111.65 in 2023. That partial recovery, even as claim volumes kept falling, suggests the remaining fentanyl prescribing is concentrating in higher-cost formulations, likely for palliative and cancer pain patients where the clinical case is clearest. The easy prescribing has been squeezed out. What remains is harder to replace.

Whether the states that led on buprenorphine access in 2016 have maintained that advantage, or whether the rest of the country has closed the gap, is the question the next decade of Part D data will answer.