Alcohol is challenging to discuss, and patients may be reluctant to disclose drinking partly because of concern about being judged. This report presents an overview of the development of a medications review intervention co-produced with the pharmacy profession and with patients, which breaks new ground by seeking to give appropriate attention to alcohol within these consultations. This intervention was developed in a series of stages and refined through conceptual discussion, literature review, observational and interview studies, and consultations with advisory groups. In this study we reflect on this process, paying particular attention to the methods used, where lessons may inform innovations in other complex clinical consultations. Early work with patients and pharmacists infused the entire process with a heightened sense of the complexity of consultations in everyday practice, prompting careful deliberation on the implications for intervention development. This required the research team to be highly responsive to both co-production inputs and data gathered in formally conducted studies, and to be committed to working through the implications for intervention design. The intervention thus evolved significantly over time, with the greatest transformations resulting from patient and pharmacist co-design workshops in the second stage of the process, where pharmacists elaborated on the nature of the need for training in particular. The original research plans provided a helpful structure, and unanticipated issues for investigation emerged throughout the process. This underscored the need to engage dynamically with changing contexts and contents and to avoid rigid adherence to any early prescribed plan. Alcohol interventions are complex and require careful developmental research. This can be a messy enterprise, which can nonetheless shed new insights into the challenges involved in optimising interventions, and how to meet them, if embraced with an attitude of openness to learning. We found that exposing our own research plans to scrutiny resulted in changes to the intervention design that gained the confidence of different stakeholders. Our understanding of the methods used, and their consequences, may be bounded by the person-centred nature of this particular intervention.