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

The recruitment status of this study is unknown because the information has not been verified recently.
Verified April 2007 by University of Cambridge.
Recruitment status was  Active, not recruiting
Sponsor:
Information provided by:
University of Cambridge
ClinicalTrials.gov Identifier:
NCT00463957
First received: April 19, 2007
Last updated: January 11, 2010
Last verified: April 2007

April 19, 2007
January 11, 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.

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Interventional
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Allocation: Randomized
Endpoint Classification: Pharmacodynamics Study
Intervention Model: Parallel Assignment
Masking: Double-Blind
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.
 
Active, not recruiting
12
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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
Male
18 Years to 55 Years
Yes
Contact information is only displayed when the study is recruiting subjects
United Kingdom
 
NCT00463957
REC 06/Q0108/200
No
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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