Introduction Chemotherapy-induced nausea and vomiting (CINV) is a common symptom in cancer, and it is one of the distressing symptoms in patients with cancer receiving chemotherapy. Information about side effects may exacerbate CINV due to the nocebo effect. This study aims to examine the efficacy of pharmacist-led enhanced support for coping with side effects during medication counselling, which includes providing information about side effects, with the goal of mitigating the nocebo effect and reducing CINV. Methods and analysis This multicentre exploratory open-label randomised controlled trial will examine the efficacy of pharmacist-led enhanced support for coping with the side effects of treatments during medication counselling in patients with advanced lung cancer. The control group will receive medication counselling as usual. The study population will consist of patients with advanced lung cancer who have not received chemotherapy and are receiving highly emetogenic chemotherapy or equivalent chemotherapy. The primary endpoint is the prevention of nausea, and the secondary endpoints include complete response (no vomiting event and no rescue medication), stress (objectively assessed using the salivary cortisol and immunoglobulin A), coping strategies and quality of life. Ethics and dissemination This study received approval from the medical ethics committee of Kansai Medical University. The results will be submitted for publication in an international peer-reviewed journal, and the findings will be presented at international scientific conferences. Protocol version 1.0, 18 Mar 2025 Trial registration number Registration number: UMIN000056068.
Fujii et al. (Sun,) studied this question.