Cannabis-based medicine may alleviate breathlessness. This study will investigate whether dronabinol, a synthetic form of ⁹-tetrahydrocannabinol (⁹-THC), reduces breathlessness in patients with severe and very severe chronic obstructive pulmonary disease (sCOPD) compared to placebo.

This single-centre, randomised, double-blinded, placebo-controlled, crossover trial will enrol 30 patients with sCOPD and persistent breathlessness despite optimal treatment. Patients will be recruited from a pulmonary outpatient clinic in Denmark over 24 months. Eligible patients (aged ≥18 years) will receive either dronabinol or placebo for 4 weeks, followed by a 2-week washout, before crossing over to the other treatment for 4 weeks. Exclusion criteria include ongoing infection, substance abuse and significant comorbidities. Primary outcome is breathing discomfort or unpleasantness measured using the 0–10 Numerical Rating Scale. Secondary outcomes include lung function (forced expiratory volume in one second), hair cortisol concentrations, functional tests, plasma THC blood concentrations and questionnaires assessing breathlessness, activity, quality of life, anxiety and depression. Continuous monitoring of vital signs, activity and sleep will be performed using a Garmin Venu 3 smartwatch. Data will be entered into electronic case report forms and monitored by the Good Clinical Practice (GCP) unit in Odense.

This will be the largest randomised, double-blinded, crossover trial to investigate dronabinol in patients with COPD and will provide new knowledge on the efficacy and safety.

Written informed consents will be obtained from study patients. The study has been approved by the Danish Medicines Agency (case number: 2023010659) and the medical research ethics committees (case number: 2301456). It is registered in the European Union Clinical Trials Registry (2024-513593-22-00) and ClinicalTrials.gov (NCT06473701). The trial follows the Declaration of Helsinki II and International Council for Harmonisation-GCP guidelines. Findings will be disseminated in peer-reviewed publications.

The European Union Clinical Trials Registry (2024-513593-22-00) and ClinicalTrials.gov (NCT06473701).