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Sildenafil and Exercise Capacity in Hypertension

This study has been completed.
Information provided by:
University of Edinburgh Identifier:
First received: January 7, 2008
Last updated: April 7, 2010
Last verified: January 2008

Hypertension (persistently elevated blood pressure) is a major risk factor for heart disease and stroke. Hypertensive individuals show a reduced exercise capacity, which is present from a very early stage and contributes to their increased cardiovascular risk. Sildenafil belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors, and it works by enhancing the effects of nitric oxide, a substance that dilates blood vessels and increases blood flow. We hypothesize that sildenafil, because of its effect on nitric oxide and blood flow, will improve exercise capacity in hypertensive patients. Therefore, the main aim of the study is to investigate the effects of PDE5 inhibition on exercise capacity and vascular function in hypertension, and to compare these effects in hypertensive patients and healthy controls.

Condition Intervention
Drug: sildenafil
Drug: hydralazine
Drug: placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator)
Official Title: Effects of the Selective Phosphodiesterase Type 5 Inhibitor Sildenafil Citrate on Exercise Capacity and Vascular Function in Hypertensive Subjects

Resource links provided by NLM:

Further study details as provided by University of Edinburgh:

Primary Outcome Measures:
  • Peak oxygen uptake (VO2) during exercise [ Time Frame: 1 week of treatment ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Exercise systolic blood pressure [ Time Frame: Maximal exercise ] [ Designated as safety issue: No ]
  • Pulse wave velocity and pulse wave analysis [ Time Frame: Before and after maximal exercise ] [ Designated as safety issue: No ]

Enrollment: 30
Study Start Date: March 2007
Study Completion Date: August 2008
Primary Completion Date: May 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1 Drug: sildenafil
50mg 3 times daily for 7 days
Other Name: Viagra
Drug: hydralazine
25mg 3 times daily for 7 days
Drug: placebo
3 times daily for 7 days
Active Comparator: 2 Drug: sildenafil
50mg 3 times daily for 7 days
Other Name: Viagra
Drug: hydralazine
25mg 3 times daily for 7 days
Drug: placebo
3 times daily for 7 days


Ages Eligible for Study:   18 Years to 70 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Male (age range: 18 - 70 years)
  • Appropriate blood pressure range
  • Hypertensive - Systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg
  • Controls - Systolic BP <140 mmHg and diastolic BP <90mmHg
  • Written informed consent

Exclusion Criteria:

  • Female
  • History of coronary artery, cerebrovascular or peripheral vascular disease within the last 6 months
  • Total cholesterol >6.5 mmol/L
  • Current alcohol abuse
  • Diabetes mellitus
  • Asthma
  • Taking any anti-hypertensive, vasoactive or endothelial function modifying drugs which cannot be withdrawn for the purpose of the study
  • ECG evidence of clinically significant arrhythmia or cardiac ischaemia
  • Clinically significant abnormality on screening blood test
  • Contraindication to strenuous exercise
  • Current involvement in other research projects
  • Other clinically relevant conditions
  • Lack of written informed consent
  Contacts and Locations
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Please refer to this study by its identifier: NCT00599235

United Kingdom
University of Edinburgh - Western General Hospital
Edinburgh, United Kingdom, EH4 2XU
Sponsors and Collaborators
University of Edinburgh
Principal Investigator: Teresa M Attinà, MD University of Edinburgh
Study Director: David J Webb, MD University of Edinburgh
  More Information

No publications provided

Responsible Party: Marise Bucukoglu, University of Edinburgh Identifier: NCT00599235     History of Changes
Other Study ID Numbers: LREC/2004/4/13, LREC/2004/4/13
Study First Received: January 7, 2008
Last Updated: April 7, 2010
Health Authority: United Kingdom: Research Ethics Committee

Keywords provided by University of Edinburgh:
Exercise capacity
PDE5 inhibitors

Additional relevant MeSH terms:
Cardiovascular Diseases
Vascular Diseases
Phosphodiesterase 5 Inhibitors
Cardiovascular Agents
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Phosphodiesterase Inhibitors
Therapeutic Uses
Urological Agents
Vasodilator Agents processed this record on November 27, 2014