Sildenafil Essay

Viagra

Viagra: What, Who, Why, and How

Sildenafil Citrate, more commonly known by the brand name Viagra, has become one of the most commonly prescribed drugs in America. Viagra is used to treat erectile dysfunction, also known as impotence. Erectile Dysfunction is best defined as the inability to maintain an erection necessary for sexual satisfaction. Sildenafil has been shown to be effective for a "broad range ED patients, including those with a history of mellitus, depression, … hypertension, diabetes, …and spinal chord injury" (Sildenafil Citrate, par. 29).

Pharmacokinetics

Viagra is taken orally. It is quickly absorbed into the system and usually reaches its peak concentration in about 30 to 120 minutes. However, as with

3). But to understand how this drug works, it is necessary to explain the physiology of erection in the normally functioning male. Under normal circumstances, sexual excitement results in the release of nitric oxide. Next, the nitric oxide will activate guanylate cyclase, an enzyme. The effect of this enzyme is an increase in the amount of cylic guanosine monophosphate. This increase produces the relaxation of the smooth muscle in the corpus cavernosum, in the penis. This relaxation is necessary to allow the inflow of blood, which is what causes an erection to

6). One of these side effects is a temporary change in blue/green color perception. This change in perception occurs because Sildenafil inhibits PDE6, "which is involved in phototransduction in the retina" (Sildenafil Citrate, par. 17). Also, Sildenafil causes a decrease in blood pressure, though the cause of this is unknown (Sildenafil Citrate, par.13); further common side effects include "headache, flushing, and upset stomach" (FDA, par. 6). Finally, it is recommended that those who take nitrates (such as nitroglycerin, often used for the treatment of angina) not take Sildenafil as it was shown to "potentiate [increase] the hypotensive effects of nitrates" (FDA, par.