BACKGROUND: Increased awareness of the world’s problematic growing healthcare expenditure and healthcare shortages requires sustainable use of available resources. To promote cultural changes in medical mindsets, societies representing medical specialties have developed new Choosing Wisely strategies. The Valais Medical Society and the Valais Pharmacy Association have developed an interprofessional collaboration project entitled ‘Less-is-more together – PPI’ to analyze and optimize change management practices focusing on the prescription and deprescription of proton pump inhibitors (PPIs) OBJECTIVE: To enhance interprofessional collaboration between physicians, pharmacists, and patients to optimize PPI use, avoid unnecessary treatments, and improve therapeutic adherence to indicated therapies. Analyze hindrances and facilitators to implementing interprofessional Less-is-more Together strategies in the field. METHODS: Home-dwelling adults domiciled in Valais and prescribed PPIs in the last six months will be invited to participate in this observational study. The studied subpopulation will be constituted of consenting patients whose physicians and pharmacists also voluntarily agree to participate. The process of collecting, pooling, transmitting, evaluating and protecting data has been validated by the Human Research Ethics Committee of the Canton Vaud. RESULTS: The ‘Primary Triple Aim’ outcome measures will be: Population health: patient’s assessment of own health, functional status, and disease burden using a monthly questionnaire for six months. Behavioral/physiological factors will be investigated using a final questionnaire at six months. Experience of care: assessment using a final questionnaire for participating patients, pharmacists, and physicians, and an analysis of negative/positive experiences via six follow-up questionnaires. Per capita cost: participants’ fluctuating or decreasing PPI intake (number of pills/dosage) and an analysis of participants’ different categories following their medical prescription, in relation to possible bias effects on the overall drug intake of the population studied. Secondary outcomes will be participation rates, patient, physician, and pharmacist follow-up, and evaluations of participants' experiences and their perceived benefits, as well as whether the interprofessional process can be improved. CONCLUSIONS: This project seeks a deeper understanding of how Less-is-more Together and smarter-medicine strategies are perceived by patients and healthcare providers in their daily lives in a very specific context. It will reveal some of the hindrances to and facilitators for efficient cultural change towards a more sustainable healthcare system. The results will be useful to optimise and scale up further Choosing Wisely approaches.