Abstract
OBJECTIVES: To review the currently available evidence on transfer strategies from methadone to sublingual buprenorphine used in clinical trials and observational studies of medication for opioid use disorder treatment, and to consider whether any strategies yield better clinical outcomes than others. METHODS: Six medical and public health databases were searched for articles and conference abstracts. The Cochrane Central Register of Controlled Trials and the World Health Organization International Clinical Trials Registry Platform were used to identify unpublished trial results. Records were dually screened, and data were extracted and checked independently. Results were summarized qualitatively and, when possible, analyzed quantitatively. RESULTS: Eighteen studies described transfer from methadone to buprenorphine. Transfer protocols were extremely varied. Most studies reported successful rates of transfer, even among studies involving transfer from high methadone doses, although lower pretransfer methadone dose was significantly associated with higher rate of successful transfer. Precipitated withdrawal was not reported frequently. A range of innovative approaches to transfer from methadone to buprenorphine remains untested. CONCLUSIONS: Few studies have used designs that enable comparison of different approaches to transfer patients from methadone to buprenorphine. Most international clinical guidelines provide recommendations consistent with the available evidence. However, clinical guidelines should be perceived as providing "guidance" rather than "protocols," and clinicians and patients need to exercise judgment when attempting transfers.