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

Erectile Dysfunction Clinical Trial

Official title:

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

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT00463957
• Other study ID #: REC 06/Q0108/200
• Status: Active, not recruiting
• Phase: N/A
• First received: April 19, 2007
• Last updated: January 11, 2010
• Start date: August 2006

Study information

• Verified date: April 2007
• Source: University of Cambridge
• Contact: n/a
• Is FDA regulated: No
• Health authority: United Kingdom: Medicines and Healthcare Products Regulatory Agency
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 12
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 55 Years

Eligibility

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

Study Design

Allocation: Randomized, Endpoint Classification: Pharmacodynamics Study, Intervention Model: Parallel Assignment, Masking: Double-Blind, Primary Purpose: Diagnostic

Related Conditions & MeSH terms

• Erectile Dysfunction

Intervention

Drug:
• sildenafil

• tadalafil

• placebo

Locations

Country	Name	City	State
United Kingdom	University of Cambridge	Cambridge

Sponsors (1)

Lead Sponsor	Collaborator
University of Cambridge

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	visual persistence
Primary	reaction time