The proportion of new buprenorphine prescriptions for opioid use disorder (OUD) that were never dispensed or filled increased from 2020 to 2024, according to this retrospective cohort study reported in JAMA Network Open. Among over 1,400 patients with commercial insurance or Medicare Advantage plans, 25.8% had abandoned buprenorphine prescriptions, defined as those not filled by patients or rejected by insurers or pharmacies. Patients with abandoned prescriptions were younger, more often Hispanic, more likely to have commercial insurance, and had higher pharmacy deductibles than those dispensed buprenorphine.