title: Sildenafil for chronic obstructive pulmonary disease: a randomized crossover trial.
abstract: BACKGROUND
  Pulmonary hypertension with exercise is common in chronic obstructive pulmonary disease (COPD) and may contribute to exercise limitation in this disease. We aimed to determine the effects of treatment with sildenafil on exercise capacity in patients with COPD and emphysema.
  
  
  METHODS
  We performed a randomized, double-blind, placebo-controlled 2-period crossover trial of sildenafil thrice daily in ten adults with COPD and emphysema on CT scan without pulmonary hypertension. We randomized study participants to 4 weeks of sildenafil (or placebo) followed by a 1-week washout and then 4 weeks of placebo (or sildenafil). The 2 primary outcomes were the 6-minute walk distance and oxygen consumption at peak exercise.
  
  
  RESULTS
  Sildenafil had no effect on 6-minute walk distance (placebo-corrected difference = -7.8 m, 95% confidence interval, -23.2 to 7.5 m, p = 0.35) or oxygen consumption at peak exercise (placebo-corrected difference = -0.1 ml/kg/min, 95% confidence interval -2.1 to 1.8 ml/kg/min, p = 0.89). Sildenafil increased the alveolar-arterial oxygen gradient (p = 0.02), worsened symptoms (p = 0.04), and decreased quality-of-life (p = 0.03). Adverse events were more frequent while receiving sildenafil (p = 0.005).
  
  
  CONCLUSIONS
  Routine sildenafil administration did not have a beneficial effect on exercise capacity in patients with COPD and emphysema without pulmonary hypertension. Sildenafil significantly worsened gas exchange at rest and quality of life. (clinicaltrials.gov NCT00104637).
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York City, New York 10032, USA. davidlederer@columbia.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Lederer
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Bartels
authors.forename: Neil W
authors.initials: NW
authors.lastname: Schluger
authors.forename: Frances
authors.initials: F
authors.lastname: Brogan
authors.forename: Patricia
authors.initials: P
authors.lastname: Jellen
authors.forename: Byron M
authors.initials: BM
authors.lastname: Thomashow
authors.forename: Steven M
authors.initials: SM
authors.lastname: Kawut
mesh_terms: D000368:Aged; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005080:Exercise Test / Q000187:drug effects*; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects*; D010879:Piperazines / Q000627:therapeutic use*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000188:drug therapy*; D011687:Purines / Q000627:therapeutic use; D011788:Quality of Life; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate