When sexual stimulation occurs, nitric oxide is released by the nervous system in the erectile tissue of the penis. Nitric oxide stimulates an enzyme that produces messenger cyclic guanosine monophosphate (cGMP). cGMP causes the arteries in the penis to dilate, so that the arteries and the erectile tissue fill with blood. An erection results. Viagra prevents cGMP from becoming degraded, so the blood flow and the erection can continue
Viagra can decrease blood supply to the optic nerve, causing sudden vision loss. This very rare adverse event occurs mainly in people with heart disease, hypertension, diabetes, high cholesterol, or pre-existing eye problems. Nobody really knows whether the vision loss was caused by the Viagra.
Viagra’s meteoric rise to fame has seen it enter usage as an illicit drug. But, Viagra use in individuals without erectile dysfunction does not seem to have any effect. Although, researchers have noted that there is a significant placebo effect. On a similar note, there is no proven benefit for women taking the drug. Viagra is a medication for erectile dysfunction. It works by relaxing your blood vessels and increasing the blood flow to your penis. According to a recent study, two out of three men who experienced erectile problems reported that taking a PDE-5 inhibitor such as Viagra improved their erection. In most cases, Viagra takes effect within 30 minutes.