BACKGROUND Excessive alcohol consumption is a significant global health issue, often unaddressed in primary care. The 15-method, a three-step opportunistic screening and treatment tool premised on Motivational Interviewing and integrated within the Screening, Brief Intervention and Referral to Treatment framework, offers a structured approach for healthcare professionals to identify and treat alcohol-related problems. The present study aimed to assess healthcare professionals' perceptions of determinants for early-stage implementation of the 15-method in Danish general practice and to classify these determinants using the Consolidated Framework for Implementation Research (CFIR).

METHODS This qualitative study involved individual interviews and group interviews with general practitioners and nurses (N = 28) from 12 general practices participating in the Identification and Treatment of Alcohol Problems in Primary Care (iTAPP) study, a stepped-wedge cluster randomized controlled trial evaluating the effectiveness of the 15-method in Danish general practice. Interviews were semi-structured, guided by the CFIR framework, and analyzed using directed content analysis. Determinants were rated for their influence on implementation.

RESULTS Key facilitators included the 15-method's adaptability, strong evidence base, relative advantage, and compatibility with existing practices. Barriers included structural characteristics in the practices and local conditions. A central finding revealed a tension between patients' motivation and healthcare professionals' opportunities and capabilities to deliver the 15-method. Mixed determinants highlighted the complexity of implementing the 15-method across diverse practices.

CONCLUSION Implementing the 15-method in Danish general practice is feasible but requires addressing specific barriers and leveraging facilitators. A multifaceted implementation strategy tailored to individual practices may be necessary to address the variations in contexts and resources across different practices with an emphasis on increasing healthcare professionals' capabilities and opportunities to deliver the intervention.