title: Conversion from sildenafil to tadalafil: results from the sildenafil to tadalafil in pulmonary arterial hypertension (SITAR) study.
abstract: OBJECTIVE
  Among phosphodiesterase type 5 inhibitors, tadalafil offers clinicians a once-daily alternative to 3 times daily sildenafil for the treatment of pulmonary arterial hypertension (PAH). This study assessed the safety and patient satisfaction with conversion from sildenafil to tadalafil.
  
  
  METHODS
  In this multicenter, prospective, 6-month study, patients with PAH were instructed to take their last dose of sildenafil in the evening and initiate tadalafil 40 mg/d the next morning. Patients completed the Treatment Satisfaction Questionnaire for Medication at baseline and 30, 90, and 180 days after transition to assess PAH symptoms and patient satisfaction. Safety was assessed on the basis of recorded adverse events (AEs).
  
  
  RESULTS
  Of the 35 patients who met the study criteria, 56% were receiving ≥2 PAH therapies. At the time of transition, the sildenafil dose ranged from 40 to 300 mg/d, with 20% of the patients on >20 mg of sildenafil 3 times daily. Transition to tadalafil was generally well tolerated, and the incidence of common AEs, except for myalgia, appeared to decrease over time on tadalafil therapy. Five (14%) patients switched back to sildenafil. A greater percentage of patients were satisfied than were dissatisfied after conversion to tadalafil (55% vs 19% at 90 days), while 26% felt about the same degree of satisfaction. Conversion to tadalafil resulted in significant improvement in patient ratings of therapy convenience.
  
  
  CONCLUSIONS
  Transition of patients from sildenafil to tadalafil was usually well tolerated, with improved convenience and may enhance treatment satisfaction.
authors.affiliation: Division of Cardiovascular Diseases, College of Medicine, Mayo Clinic, Rochester, MN, USA frantz.robert@mayo.edu.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Frantz
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Louise
authors.initials: L
authors.lastname: Durst
authors.affiliation: Division of Pulmonary Medicine, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Burger
authors.affiliation: Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Oudiz
authors.affiliation: Cardiovascular Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Bourge
authors.affiliation: Cardiovascular Medicine, Ohio State University Medical Center, Columbus, OH, USA.
authors.forename: Veronica
authors.initials: V
authors.lastname: Franco
authors.affiliation: Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Waxman
authors.affiliation: United Therapeutics Corporation, Research Triangle Park, NC, USA.
authors.forename: Susanne
authors.initials: S
authors.lastname: McDevitt
authors.affiliation: United Therapeutics Corporation, Research Triangle Park, NC, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Walker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D062186:Arterial Pressure / Q000187:drug effects*; D002243:Carbolines / Q000009:adverse effects / Q000627:therapeutic use*; D057915:Drug Substitution; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D058986:Phosphodiesterase 5 Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000187:drug effects* / Q000503:physiopathology; D011687:Purines / Q000009:adverse effects / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000009:adverse effects / Q000627:therapeutic use*; D011795:Surveys and Questionnaires; D000068581:Tadalafil; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014665:Vasodilator Agents / Q000009:adverse effects / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D002243:Carbolines; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D014665:Vasodilator Agents; D000068581:Tadalafil; D000068677:Sildenafil Citrate
keywords: patient satisfaction; pulmonary arterial hypertension; sildenafil; switch; tadalafil