Patients with erectile dysfunction and no history of eye disorder are described in detail elsewhere. Morales and associates have summarized the clinical safety of sildenafil in phase II/II clinical trials. In 6 flexible-dose studies comparing the efficacy of sildenafil (734 patients) with placebo (725 patients), abnormal vision was reported by 3% of those treated with [...]

The first study examined the effects of increasing doses of sildenafil on the results of several visual function tests. A double-blind, placebo-controlled, crossover, Phase II study assessed the acute effects (1 to 24 hours) of sildenafil (50 to 200 mg) in 16 healthy male volunteers. Sildenafil did not produce clinically significant changes in visual acuity, [...]

Cognizant of the preclinical data, substantial efforts were made to investigate the visual effects of sildenafil during clinical development. A number of Phase II and III studies were carried out to determine the safety of sildenafil in relation to the retina and visual function. Much of the data, with complete study descriptions, will appear in [...]

Early in preclinical development, it was found that sildenafil inhibits retinal PDE6 enzymes with an IC50 of 27-58 nM. Although this was substantially less than its effect on the intended target, PDE5 (IC50 3.9 nM), it led to the evaluation of safety of high doses of sildenafil on retinal histopathology in rats and dogs and [...]

Viagra (sildenafil citrate) is the first of a new class of orally effective treatments for erectile dysfunction. It potently inhibits cGMP-specific phosphodiesterase type 5 (PDE5) (Fig 1),

found in high concentrations in the smooth-muscle cells of corpus cavernosum and in lesser concentrations in blood vessels of the systemic circulation. Because of its ability to act as [...]

To date, sildenafil citrate (Viagra) gives every evidence of being a safe drug for the eye despite a series of expressed concerns. A review of how its ocular safety profile has been identified offers insights into the strengths and weaknesses of present systems and resources for judging the ocular safety of Viagra or, for that [...]

Viagra is the first FDA approved pill for the treatment of men who have difficulty having and maintaining an erection (impotence). The primary chemical ingredient used in Viagra is sildenafil citrate. It is a convenient, discreet pill you take only when you want to have sex. Viagra can help many men suffering from erectile dysfunction [...]