Sildenafil is the active ingredient in Kamagra. It is also sold under a number of other brand names including Viagra, Eriacta, Intimax, and many more. Such tablets are sometimes referred to as blue or green pills, and blue or green diamonds. Sildenafil is generally used to treat Erectile Dysfunction, also known as Male Impotence, and may also be used to treat Pulmonary Hypertension, and Pulmonary Arterial Hypertension. Its efficacy in the treatment of sexual dysfunction in women remains to be verified by scientific testing.
Common side effects of Sildenafil include headaches, facial and skin flushing, and mild nausea. Rare but serious side effects include prolonged erections known as priapasms, which can lead to damage to the penis, and possibly sudden-onset hearing loss. Sildenafil should not be taken by people who take nitrates because this can result in a severe and dangerous drop in blood pressure. Again, medical consultation is always advised in view of these potential dangers. Pictured below is a 3D rendering of the Sildenafil molecule.
This is a link to the Wikipedia article on Sildenafil, where more in depth technical information and historical background can be found.
Caution should be exercised by persons who also take protease inhibitors (for the treatment of HIV), as these may inhibit the metabolism of sildenafil, effectively multiplying the plasma levels of sildenafil, and possibly therefore increasing the incidence and severity of associated side effects. Those using protease inhibitors are recommended to limit their use of sildenafil to no more than one 25mg dosage within 48 hours. Other drugs that interfere with the metabolism of sildenafil include erythromycin and cimetidine, both of which can also lead to prolonged plasma half life.
The simultaneous use of sildenafil and alpha blockers can lead to low blood pressure, although this should not occur if they are taken at four hours or more apart.
Do not take Sildenafil, if
. You take any nitric oxide donors, and organic nitrites and nitrates such as glyceryl trinitrate (nitroglycerin), sodium nitroprusside, and amyl nitrite (Poppers)
. Sexual intercourse is not advised due to cardiovascular risk factors. Serious impairment in renal (kidney) function.
. You suffer from serious hepatic impairment (decreased liver function)
. You suffer from low blood pressure (hypotension).
. You have had a recent stroke or heart attack.
. Your suffer with hereditary degenerative retinal disorders, including genetic disorders of retinal phosphodiesterases.