Discontinuation of medications such as methadone and buprenorphine amongst patients receiving opioid agonist treatment (OAT) is an international phenomenon. Recent developments in OAT medication include depot-injections of buprenorphine. Circumstances underlying discontinuation of these new formulations of medication are not fully understood from a qualitative perspective.Data derive from a longitudinal qualitative study of patients' experience of long-acting injectable buprenorphine (LAIB), involving semi-structured telephone-interviews held at six-points in time. The relevant dataset for this article consists of 44 interview transcripts, generated from 8 participants who were each affected by discontinuation of LAIB prescriptions (during the first 12-months of treatment). Analyses sought to identify circumstances associated with LAIB discontinuation and data were further situated within a framework of 'evidence making intervention' and associated 'matters-of-concern'. Matters-of-concern relate to the ways in which an intervention is 'made' and constructed through engagement and practice, from the perspective of the recipient.In this study, participants experienced either 'discontinuation of LAIB prescriptions by treatment services' or patient-led 'opt-out' from treatment. Matters-of-concern underlying the former were associated with late attendance for scheduled appointments, non-prescribed substance use or receiving a custodial sentence. Matters-of-concern relating to patient-initiated discontinuation were associated with personal circumstances that affected treatment motivation, side-effects (of buprenorphine), a preference to resume heroin use, or because individual treatment goals had been achieved.The assorted matters-of-concern that influence discontinuation of LAIB demonstrate that such OAT is complex and multi-faceted, is neither fixed nor stable, and does not generate universally shared outcome. Experiences of LAIB discontinuation are shaped by a wide range of social, temporal and treatment-related effects that include disconnected therapeutic alliance between patient and treatment providers. In order to maximise the benefits of LAIB it is necessary to develop meaningful therapeutic alliances (notwithstanding policy boundaries) to enable exploration of matters-of-concern during treatment.