Prescription amphetamines in people with opioid use disorder and co-occurring psychostimulant use disorder initiating buprenorphine: an analysis of treatment retention and overdose risk

BACKGROUND: Attention-deficit and hyperactivity disorder (ADHD) is frequently diagnosed in patients with substance use disorders (SUDs), including opioids. There remains concern about the safety and efficacy of prescription amphetamines (PAs) and their impact on effectiveness of opioid use disorder (OUD) treatment with buprenorphine. OBJECTIVES: To assess the effect of PAs on OUD buprenorphine treatment retention and/or SUD-related emergency admission or drug-related poisonings. METHODS: We used a retrospective cohort design with a secondary analysis of data from Merative MarketScan Commercial and Multi-State Medicaid Databases from 1 January 2006 to 31 December 2016. Individuals included were aged 12–64 years, had an OUD diagnosis and were prescribed buprenorphine. Our analysis used multivariable Cox regression to evaluate the relationship between PA receipt and time to buprenorphine discontinuation. The second part focused on subsamples of buprenorphine initiators who had either (1) any SUD-related emergency admissions or (2) drug-related poisoning. These outcomes were modelled as a function of PA exposure using conditional logistic regression models as part of a within-person, case-crossover design. FINDINGS: Our sample had 90 269 patients with OUD (mean age 34.2 years (SD=11.3)) who initiated buprenorphine. Being prescribed a PA was associated with improved buprenorphine retention among individuals both with (adjusted HR (aHR) 0.91 (95% CI 0.86 to 0.97)) and without a concurrent psychostimulant use disorder (PSUD) (aHR 0.92 (95% CI 0.90 to 0.93)). CONCLUSIONS: PA use was associated with improved buprenorphine retention in people with OUD with and without co-occurring PSUD. The risks of acute SUD-related events and drug-related poisonings associated with PA use did not differ when comparing PA-using days with days without PA use. CLINICAL IMPLICATIONS: Patients with OUD on buprenorphine should receive treatment with a PA when indicated.