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Effect of Regular Sildenafil on Blood Pressure and Arterial Function in Hypertension

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: April 24, 2006
Last Update Posted: April 24, 2006
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.
Information provided by:
University of Edinburgh
The purpose of the study is to investigate if regular treatment with sildenafil reduces blood pressure and improves blood vessel function in patients with hypertension (high blood pressure).

Condition Intervention Phase
Hypertension Drug: Sildenafil citrate Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double
Primary Purpose: Treatment
Official Title: Effects of Regular Treatment With Sildenafil on Blood Pressure and Endothelial Function in Untreated Hypertensives

Resource links provided by NLM:

Further study details as provided by University of Edinburgh:

Primary Outcome Measures:
  • Change in blood pressure
  • Change in flow-mediated dilatation
  • Change in central augmentation index (derived from pulse wave analysis)
  • Change in carotid-femoral pulse wave velocity

Estimated Enrollment: 20
Study Start Date: March 2004
Estimated Study Completion Date: November 2005
Detailed Description:

Inhibitors of phosphodiesterase type 5 (PDE5), such as sildenafil, relax blood vessels. In the penis this facilitates erection and sildenafil has proved a very effective treatment for male erectile dysfunction.

To date, most work on the effects of sildenafil on blood pressure have mainly been investigated in single dose studies. These have shown that sildenafil causes a modest reduction in blood pressure, even when taken with other blood pressure-lowering drugs, providing reassurance on safety when taken as a single dose for erectile dysfunction. However, these studies do not offer any insight into the potential of PDE5 inhibition in the long-term treatment of hypertension. We will address this question by investigating the effects of regular administration of sildenafil on blood pressure. It may also be postulated that, because of its mechanism of action, sildenafil will also improve the function of the endothelium, the single layer of cells that lines all blood vessels. Therefore, the effect of regular sildenafil on endothelial function in hypertension will also be investigated in the study.

The study will be performed in a randomised, placebo-controlled, double blind, 2-way crossover manner. Sildenafil and matched placebo will each will taken three times daily for 2 weeks, with a washout of at least 6 days between treatments. Measurements will be made acutely (before and 1 hour after oral sildenafil) of heart rate, blood pressure, pulse wave analysis (a measure of wave reflection in arteries), pulse wave velocity (a measure of arterial stiffness) and flow-mediated dilatation (a measure of endothelial function). These measurements will be repeated 2 weeks later (again just before and 1 hour after oral sildenafil). In addition, ambulatory blood pressure will be recorded after 2 weeks of treatment (baseline ambulatory BP will be taken as the recording made at diagnosis).


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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Male or female
  • Hypertensive (office systolic BP ≥160 mmHg or diastolic BP ≥100 mmHg), not taking antihypertensive drugs OR hypertensive controlled (systolic BP < 160 mmHg or diastolic BP < 100 mmHg) on 1 antihypertensive agent
  • Hypertension confirmed on ambulatory monitoring (average daytime BP ≥145/95 mmHg)
  • Patients will also be included if they have ‘borderline’ hypertension and their calculated 10-year risk of cardiovascular disease is >20% or they have target organ damage. Borderline hypertension will be defined according to ambulatory BP criteria alone (average awake systolic BP ≥135 and <145 mmHg or diastolic BP ≥85 and <95 mmHg).

Exclusion Criteria:

  • History of other major cardiac, respiratory, neurological or renal disease
  • Systolic BP consistently >210 mmHg or diastolic BP consistently >120 mmHg
  • Systolic BP consistently >180 mmHg or diastolic BP consistently >110 mmHg in those withdrawn from existing therapy
  • Current alcohol abuse
  • Diabetes
  • Taking vasoactive drugs
  • Previous serious drug allergy
  • Pregnant
  • Participation, within 6 months, in other research studies
  Contacts and Locations
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 ClinicalTrials.gov identifier (NCT number): NCT00317421

United Kingdom
Clinical Pharmacology Unit, University of Edinburgh
Edinburgh, Lothian, United Kingdom, EH4 2XU
Sponsors and Collaborators
University of Edinburgh
Principal Investigator: James J Oliver, MBChB University of Edinburgh
  More Information

ClinicalTrials.gov Identifier: NCT00317421     History of Changes
Other Study ID Numbers: JO-02
First Submitted: April 20, 2006
First Posted: April 24, 2006
Last Update Posted: April 24, 2006
Last Verified: February 2004

Keywords provided by University of Edinburgh:
Phosphodiesterase 5
Blood pressure
Arterial stiffness
Endothelial function

Additional relevant MeSH terms:
Vascular Diseases
Cardiovascular Diseases
Sildenafil Citrate
Vasodilator Agents
Phosphodiesterase 5 Inhibitors
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Urological Agents