The Pharmacological Basis for the Increase in Visual Time Constants Induced by Single Oral Doses of Sildenafil
Status:
Unknown status
Trial end date:
1969-12-31
Target enrollment:
Participant gender:
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.