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Sildenafil to Increase Exercise Capacity in Individuals With Idiopathic Pulmonary Fibrosis and Pulmonary Hypertension

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00352482
Recruitment Status : Completed
First Posted : July 14, 2006
Last Update Posted : July 29, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that affects an individual's ability to breathe. Currently, no medications can reverse the damage to the lungs caused by IPF, but individuals are encouraged to engage in moderate exercise to strengthen lung function. This study will evaluate the effectiveness of sildenafil at improving exercise tolerance and breathing difficulties in individuals with IPF.

Condition or disease Intervention/treatment Phase
Pulmonary Fibrosis Hypertension, Pulmonary Drug: Sildenafil (50 mg) Phase 2

Detailed Description:

IPF is a disease that damages the air sacs in the lungs and leads to widespread and permanent scarring of lung tissue. Individuals with IPF may experience breathing difficulties, cough, chest pain, and a decreased exercise capacity. There is no cure for this disease, and individuals usually die within 3 to 5 years. It is recommended that individuals with IPF engage in moderate exercise, as this can help maintain strength and improve lung function. Many individuals with IPF also suffer from pulmonary hypertension, which is high blood pressure in the arteries leading to the lungs. Sildenafil, a medication currently used to treat pulmonary hypertension, increases blood flow to the lungs and enhances gas exchange within the lungs. The purpose of this study is to evaluate the effectiveness of sildenafil at improving exercise tolerance and breathing difficulties in individuals with IPF and pulmonary hypertension.

This 3-week study will enroll individuals with IPF and pulmonary hypertension. Study visits will occur at baseline, and Weeks 1 and 2. At the baseline visit, participants will perform a 6-minute walk test, which will measure the distance walked in a 6-minute period. Oxygen levels will be measured prior to and during the test, and standardized questionnaires will be completed to assess breathing difficulties. A second 6-minute walk test will be performed 1 hour following the first test. At the Week 1 visit, participants will be randomly assigned to receive a single dose of either 50 mg of sildenafil or placebo. One hour after receiving the medication, they will complete another 6-minute walk test. The Week 2 visit will be identical to the Week 1 visit, except participants who received sildenafil at Week 1 will receive placebo at Week 2, and vice versa.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 20 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double
Primary Purpose: Treatment
Official Title: Sildenafil Treatment in Patients With Idiopathic Pulmonary Fibrosis and Pulmonary Hypertension - a Pilot Cross-over Study
Study Start Date : November 2004
Actual Study Completion Date : July 2007

Primary Outcome Measures :
  1. 6-minute walk distance (measured at Week 3)

Secondary Outcome Measures :
  1. Oxygen saturation (SpO2) at rest
  2. Lowest SpO2 with exertion (measured during 6-minute walk test)
  3. Total duration of SpO2 below 89% with exertion (measured during 6-minute walk test)
  4. Recovery time (measured during 6-minute walk test)
  5. Mean SpO2 and area under the curve (measured during 6-minute walk test)
  6. Desaturation index (measured by the 6-minute walk distance multiplied by the SpO2 mean value)
  7. Level of breathlessness (measured by Borg dyspnea index questionnaire) (all measured at Week 3)

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   19 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • IPF, diagnosed according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) consensus statement (with or without surgical lung biopsy)
  • Pulmonary hypertension, defined as mean pulmonary artery pressure (MPAP) greater than or equal to 25 mm Hg by right heart catheterization (RHC)

Exclusion Criteria:

  • Interstitial lung disease due to conditions other than IPF
  • Recent lung or upper respiratory tract infection within 4 weeks of study entry
  • Acute or chronic impairment other than dyspnea (e.g., angina pectoris, intermittent claudication) limiting the ability to comply with study requirements (e.g., 6-minute walk test)
  • Known hypersensitivity to sildenafil
  • Known or suspected coronary artery disease (CAD)
  • Unstable angina
  • Nitrate use
  • Known or suspected aortic stenosis (AS)
  • Known or suspected heart attack, stroke, or life-threatening arrythmias within 1 month of study entry
  • Severe chronic heart failure, defined as New York Heart Association (NYHA) class III/IV and/or left ventricular ejection fraction less than 25%
  • Known penile deformities
  • Known kidney or liver dysfunction
  • Uncontrolled diabetes (blood glucose less than 60 mg/dl or greater than 300 mg/dl)
  • Severe serum sodium abnormalities (serum sodium less than 130 mEq/L or greater than 150 mEq/L)
  • Condition that may predispose participant to priapism (e.g., sickle cell anemia, multiple myeloma, leukemia)
  • Retinitis pigmentosa
  • Known or suspected idiopathic hypertrophic subaortic stenosis (IHSS)
  • Low blood pressure (systolic blood pressure [SBP] less than 100 mm Hg or diastolic blood pressure [DBP] less than 50 mm Hg)
  • Uncontrolled systemic high blood pressure (SBP greater than 180 mm Hg or DBP greater than 100 mm Hg)
  • Cardiopulmonary rehabilitation program started within 8 weeks of study entry or likely to start prior to the conclusion of the study
  • Treatment with an endothelin receptor antagonist, iloprost, epoprostenol, inhibitors of CYP3A4 (e.g., cimetidine, erythromycin, ketoconazole, itraconazole, mibefradil), protease inhibitors (e.g., amprenavir, indinavir, or ritonavir), rifampin, alpha-blockers (e.g., doxazosin), or other phosphodiesterase-5 inhibitors
  • Current use of alcohol, grapefruit juice, or St. John's wort
  • Pregnant or breastfeeding

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00352482

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United States, California
UCLA Pulmonary Outpatient Clinic,
Los Angeles, California, United States, 90095
Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
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Principal Investigator: David A. Zisman, MD University of California, Los Angeles
Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
Layout table for additonal information Identifier: NCT00352482    
Other Study ID Numbers: 414
P50HL067665-05 ( U.S. NIH Grant/Contract )
First Posted: July 14, 2006    Key Record Dates
Last Update Posted: July 29, 2016
Last Verified: December 2007
Keywords provided by National Heart, Lung, and Blood Institute (NHLBI):
Pulmonary Hypertension
Idiopathic Pulmonary Fibrosis
Additional relevant MeSH terms:
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Hypertension, Pulmonary
Pulmonary Fibrosis
Idiopathic Pulmonary Fibrosis
Vascular Diseases
Cardiovascular Diseases
Pathologic Processes
Lung Diseases
Respiratory Tract Diseases
Sildenafil Citrate
Vasodilator Agents
Phosphodiesterase 5 Inhibitors
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Urological Agents