Oral Sildenafil for COPD
Trial Summary
What is the purpose of this trial?
Chronic obstructive pulmonary disease (COPD) is a condition characterized by airway obstruction. Patients with COPD experience significant shortness of breath on exertion. The mechanisms responsible for shortness of breath on exertion are well understood in moderate and severe COPD, but, are poorly understood in mild COPD where symptoms appear disproportionate to the degree of airway obstruction. Mild COPD patients show an exaggerated breathing response to exercise, determined by the breathing response to carbon dioxide production (V̇E/V̇CO2). Recent work suggests that the increased V̇E/V̇CO2 during exercise in mild COPD is secondary to increased deadspace (i.e. lung regions with ventilation but no perfusion) and/or ventilation/perfusion (V̇A/Q) inequality (poor matching of ventilation to perfusion). Researchers have proposed that the increased deadspace or V̇A/Q inequality is secondary to pulmonary vascular dysfunction and hypoperfusion of the pulmonary capillaries. Recently, we have shown that inhaled nitric oxide, a potent dilator of pulmonary vasculature, reduces shortness of breath and V̇E/V̇CO2, and improves exercise capacity in mild COPD. This preliminary finding suggests that pulmonary vascular dysfunction is an important contributor to exercise intolerance in mild COPD. Here, we aim to test whether sildenafil, an oral pulmonary vasodilator, can improve exercise tolerance and shortness of breath in mild COPD.
Will I have to stop taking my current medications?
If you are currently taking phosphodiesterase type-5 inhibitors, nitrates, opioids, azole antifungals, macrolide antibiotics, protease inhibitors, alpha blockers, riociguat, mifepristone, or rifamycin, you will need to stop these medications to participate in the trial.
What evidence supports the effectiveness of the drug Sildenafil Citrate for COPD?
Is oral sildenafil safe for humans?
How does the drug Sildenafil Citrate differ from other treatments for COPD?
Sildenafil Citrate, commonly used for erectile dysfunction, is unique for COPD treatment because it can improve exercise capacity and reduce pulmonary arterial pressure, which are not typical targets of standard COPD therapies. Unlike other treatments, it works by relaxing blood vessels in the lungs, potentially improving breathing and exercise tolerance.1231011
Research Team
Michael K Stickland, Ph.D.
Principal Investigator
University of Alberta
Eligibility Criteria
This trial is for adults with mild COPD who experience significant shortness of breath. Participants must have a specific lung function level (FEV1 >30% predicted) and can't be on certain medications or have heart conditions that limit exercise. Women able to bear children must use contraception, and postmenopausal women must be amenorrheic for at least 12 months.Inclusion Criteria
Exclusion Criteria
Trial Timeline
Screening
Participants are screened for eligibility to participate in the trial
Treatment
Participants receive oral sildenafil or placebo in a randomized, double-blinded, placebo-controlled cross-over design
Follow-up
Participants are monitored for safety and effectiveness after treatment
Treatment Details
Interventions
- Placebo (Other)
- Sildenafil Citrate (Phosphodiesterase-5 Inhibitor)
Find a Clinic Near You
Who Is Running the Clinical Trial?
University of Alberta
Lead Sponsor
Bill Flanagan
University of Alberta
Chief Executive Officer since 2020
LLB from University of Toronto, LLM from Columbia University
Dr. Verna Yiu
University of Alberta
Chief Medical Officer since 2012
MD from University of Alberta, Fellowship in Pediatric Nephrology at Harvard University
Canadian Institutes of Health Research (CIHR)
Collaborator
Dr. Paul C. Hébert
Canadian Institutes of Health Research (CIHR)
Chief Executive Officer
MD, University of Ottawa
Dr. Paul C. Hébert
Canadian Institutes of Health Research (CIHR)
Chief Medical Officer
MD, University of Ottawa