RESUMEN
We explore, from the perspective of primary care health professionals, the motivations that lead patients to not initiate prescribed treatments, by developing a qualitative study in Spanish primary care. Six focus groups (N = 46) were conducted with general practitioners, nurse practitioners, social workers and community pharmacists and carried out in primary care (PC) of Barcelona Province, from April to July of 2018. The 46 participants were identified by three general practitioners and two pharmacists. In the interviews, the reasons for non-initiation of PC patients' medication were explored. Triangulated content analysis was performed. Patients' perspective, analysed in a previous study, and professionals' perspective agree on most of the factors that affect non-initiation. New factors were categorized into existent categories, confirming, and supplementing the model developed with patients. Health professionals identified some new factors which were not present in the patients' discourse, such as stigma related to the drug, hidden reasons for consultation, the role of nurses in prescription and support, the role of the pharmacy technician, illiteracy and lack of social support. The professionals confirm and expand on the Theoretical Model of Medication Non-Initiation. Primary care professionals should consider the factors described when prescribing a new medication. Knowledge contributed by the model should guide the design of interventions to improve initiation.