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The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil

Primary Purpose

Erectile Dysfunction

Status
Unknown status
Phase
Not Applicable
Locations
United Kingdom
Study Type
Interventional
Intervention
sildenafil
tadalafil
placebo
Sponsored by
University of Cambridge
About
Eligibility
Locations
Outcomes
Full info

About this trial

This is an interventional diagnostic trial for Erectile Dysfunction focused on measuring sildenafil, tadalafil, phosphodiesterase, visual persistence, reaction time

Eligibility Criteria

18 Years - 55 Years (Adult)MaleAccepts Healthy Volunteers

Inclusion Criteria:

  • Healthy
  • Male
  • 18-55 years

Exclusion Criteria:

  • Significant medical or psychiatric illness
  • Cardiac disease
  • Hyper or hypotension
  • Renal disease
  • Liver disease
  • Stroke
  • Sickle cell anaemia
  • Multiple myeloma
  • Leukaemia
  • Bleeding disorders
  • Peyronie's disease
  • Priapism
  • Subjects receiving prescribed medications
  • Subjects with known visual abnormalities other than refractive errors, including retinitis pigmentosa, optic neuropathy

Sites / Locations

  • University of Cambridge

Outcomes

Primary Outcome Measures

visual persistence
reaction time

Secondary Outcome Measures

Full Information

First Posted
April 19, 2007
Last Updated
January 11, 2010
Sponsor
University of Cambridge
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1. Study Identification

Unique Protocol Identification Number
NCT00463957
Brief Title
The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil
Official Title
The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil
Study Type
Interventional

2. Study Status

Record Verification Date
April 2007
Overall Recruitment Status
Unknown status
Study Start Date
August 2006 (undefined)
Primary Completion Date
undefined (undefined)
Study Completion Date
undefined (undefined)

3. Sponsor/Collaborators

Name of the Sponsor
University of Cambridge

4. Oversight

Data Monitoring Committee
No

5. Study Description

Brief Summary
Sildenafil and similar drugs have been used for several years to treat erectile dysfunction. It has been noticed that in some people, sildenafil causes a subtle increase in the length of time that visual images that we see are retained by the retina. It is thought that this might be due to an effect of sildenafil on inhibiting an enzyme called phosphodiesterase type 6 (PDE6) which is present in the retina. By giving single oral doses of sildenafil and a similar drug called tadalafil which has less effect on PDE6, we hypothesise that this is the mechanism of the change in vision caused by sildenafil. By performing computerised visual test, we plan to compare the effects of sildenafil, tadalafil and placebo tablets on vision in healthy volunteers.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Erectile Dysfunction
Keywords
sildenafil, tadalafil, phosphodiesterase, visual persistence, reaction time

7. Study Design

Primary Purpose
Diagnostic
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
Double
Allocation
Randomized
Enrollment
12 (false)

8. Arms, Groups, and Interventions

Intervention Type
Drug
Intervention Name(s)
sildenafil
Intervention Type
Drug
Intervention Name(s)
tadalafil
Intervention Type
Drug
Intervention Name(s)
placebo
Primary Outcome Measure Information:
Title
visual persistence
Title
reaction time

10. Eligibility

Sex
Male
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
55 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility Criteria
Inclusion Criteria: Healthy Male 18-55 years Exclusion Criteria: Significant medical or psychiatric illness Cardiac disease Hyper or hypotension Renal disease Liver disease Stroke Sickle cell anaemia Multiple myeloma Leukaemia Bleeding disorders Peyronie's disease Priapism Subjects receiving prescribed medications Subjects with known visual abnormalities other than refractive errors, including retinitis pigmentosa, optic neuropathy
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Morris J Brown
Organizational Affiliation
University of Cambridge
Official's Role
Principal Investigator
Facility Information:
Facility Name
University of Cambridge
City
Cambridge
Country
United Kingdom

12. IPD Sharing Statement

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The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil

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