Kraichgauer wrote:
After hearing all this wonderful news about Viagra, dare I ask - are there any negative side effects?
yes, it may cause a blue tinge to appear in some people's vision - according to reports by Pfizer and subsequent studies, ocular side effects occur in:
about 3 percent of men taking doses of 25-50 mg
about 11 percent taking 100 mg doses
about 50 percent of men taking 200 mg
nearly all men taking 600 to 800 mg.
why does Viagra cause vision changes? Viagra is effective on erectile dysfunction because it inhibits phosphodiesterase 5 (PDE-5), an enzyme that enhances the effects of nitric oxide, which is released during sexual stimulation to relax the smooth muscle of the penis and facilitate blood inflow. However, the drug also has a milder inhibiting effect on PDE-6, an enzyme actively present in retinal photoreceptors. this causes an increase in the concentration of cyclicGMP, resulting in a depolarization of the rod cell – and increased light sensitivity and the infamous "blue vision."
when do side effects occur? The side effects are short-lived and generally peak within 1-2 hours after the drug is taken. what is the long-term vision damage? so far, no long-term retinal damage has been reported, but then again, long-term electroretinograms (ERG) have not been done, says Michael F. Marmor, MD, a Stanford retinal specialist who has published studies on the ophthalmic effects of Viagra. he believes the drug could conceivably result in lasting damage to photoreceptors, so he recommends that you avoid it if you have macular degeneration, diabetic retinopathy, retinitis pigmentosa or other retinal disease. (meanwhile, Viagra's own label issues warnings to patients with existing AMD or retinitis pigmentosa because they were not studied in past clinical trials.)
also, it may cause other vision/hearing acuity problems which may be permanent, likely caused by blown-out capillaries hemorrhaging blood and destroying wholesale numbers of cells therein. sildenafil and other PDE-5-based drugs do not discriminate which blood vessels they do their nitric oxide magic on, so the fragile blood vessels of the hearing and visual mechanism could be collaterally damaged. these are rare problems but they do occur with some regularity in the literature. so it would seem some men might ask themselves, "
do i wanna see and hear well, or do i wanna cum?" what a choice.