Prior Authorization for Opioid Use Disorder Versus Pain Medications: Lessons Learned for Parity Enforcement

Objective: This study characterized the use of prior authorization for opioid use disorder medications as compared with that for opioid pain medications in the United States among Medicare Part D plans. Method: Medicare Part D formulary data from 2017-2019 were used to describe differences in prior authorization between opioid use disorder medications and opioid pain medications. Results: In 2017, 72% of Medicare Part D formularies required prior authorization for brand buprenorphine-naloxone, whereas 6% of formularies required prior authorization for brand oxycodone. In 2019, 3% of formularies required prior authorization for brand buprenorphine-naloxone, whereas 16% of formularies required prior authorization for brand oxycodone. Throughout the study period, other formulary restrictions such as quantity limits were similar for both medications. Conclusions: The disparate use of prior authorization in 2017 for opioid use disorder medications as compared with opioid pain medications suggests that formulary decision making may be inconsistent between medications used to treat substance use disorders and those used to treat pain. If Part D formularies publicly released their decision-making criteria, then there would be a greater understanding of why prior authorization was differentially applied. Greater transparency would help ensure that formulary decisions are not the result of biases and stigma toward substance use disorders.