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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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ClinicalTrials.gov Identifier: NCT00463957
Recruitment Status : Unknown
Verified April 2007 by University of Cambridge.
Recruitment status was:  Active, not recruiting
First Posted : April 20, 2007
Last Update Posted : January 12, 2010
Sponsor:
Information provided by:
University of Cambridge

April 19, 2007
April 20, 2007
January 12, 2010
August 2006
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  • visual persistence
  • reaction time
Same as current
Complete list of historical versions of study NCT00463957 on ClinicalTrials.gov Archive Site
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The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil
The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil
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.
Not Provided
Interventional
Not Applicable
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double
Primary Purpose: Diagnostic
Erectile Dysfunction
  • Drug: sildenafil
  • Drug: tadalafil
  • Drug: placebo
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Unknown status
12
Same as current
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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
Sexes Eligible for Study: Male
18 Years to 55 Years   (Adult)
Yes
Contact information is only displayed when the study is recruiting subjects
United Kingdom
 
 
NCT00463957
REC 06/Q0108/200
No
Not Provided
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University of Cambridge
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Principal Investigator: Morris J Brown University of Cambridge
University of Cambridge
April 2007

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP