Background The Beta-blockers Or Placebo for Primary Prophylaxis of oesophageal varices (BOPPP) trial is a 3-year phase IV, multi-centre clinical trial of investigational medicinal product (CTIMP) that aims to determine the effectiveness of carvedilol in the prevention of variceal bleeding for small oesophageal varices in patients with cirrhosis. Early engagement of General Practitioners (GPs) in conversations about delivery of a potentially effective secondary care-initiated treatment in primary care provides insights for future implementation. The aim of this study was to understand the implementation of trial findings by exploring i) GP perspectives on factors that influence implementation beyond the context of the trial and ii) how dose titration and ongoing treatment with carvedilol is best delivered in primary care. Methods This qualitative study was embedded within the BOPPP trial and was conducted alongside site opening. GP participants were purposively sampled and recruited from ten Clinical Commissioning Groups in England and three Health Boards across Wales. Semi-structured telephone individual interviews were conducted with GPs (n = 23) working in England and Wales. Data were analysed using reflexive thematic analysis. Findings Five overarching themes were identified: i) primary care is best placed for oversight, ii) a shared approach led by secondary care, iii) empower the patient to take responsibility, iv) the need to go above and beyond and v) develop practice guidance. The focus on prevention, attention to holistic care, and existing and often long-standing relationships with patients provides an impetus for GP oversight. GPs spoke about the value of partnership working with secondary care and of prioritising patient-centred care and involving patients in taking responsibility for their own health. An agreed pathway of care, clear communication, and specific, accessible guidance on how to implement the proposed treatment strategy safely and effectively are important determinants in the success of implementation. Conclusions Our findings for implementing secondary care-initiated treatment in primary care are important to the specifics of the BOPPP trial but can also go some way in informing wider learning for other trials where work is shared across the primary-secondary care interface, and where findings will impact the primary care workload. We propose a systems research perspective for addressing implementation of CTIMP findings at the outset of research. The value of early stakeholder involvement is highlighted, and the need to consider complexity in terms of the interaction between the intervention and the context in which it is implemented is acknowledged.