Overview Safety and Efficacy of Sildenafil in Cystic Fibrosis (CF) Lung Disease Status: Completed Trial end date: 2012-12-01 Target enrollment: Participant gender: Summary The purpose of this study is to determine whether sildenafil can decrease inflammation in CF lung disease. Phase: Phase 1/Phase 2 Details Lead Sponsor: National Jewish HealthCollaborators: Cystic Fibrosis FoundationCystic Fibrosis Foundation TherapeuticsTreatments: Phosphodiesterase InhibitorsSildenafil Citrate