Viagra (sildenafil) tablets are provided in dosages of 25, 50 and 100 milligrams. The pills are blue, rounded-diamond- shaped, film coated tablets. Make sure you except no substitute. While some web sites say they are dispensing Viagra, in truth they are dispensing a cheap substitute. Only pills with the above configuration are the genuine product.

HOW DOES VIAGRA WORK?

Viagra is the brand name for sildenafil. When sexual stimulation begins nitric oxide (NO) is released into the spongy tissue of the penis. NO then activates an enzyme that increases the production of cyclic guanosine monophosphate (cGMP) the substance that relaxes the spongy tissue of the penis and facilitates an influx of blood. As specific enzymes slowly degrade cGMP the penis will slowly loose its ability to sustain an erection. Viagra works by inhibiting those enzymes that degrade cGMP, thereby enhancing ones ability to obtain and sustain an erection.

HOW EFFECTIVE IS VIAGRA?

Over 21 studies have been done to evaluate the efficacy of Viagra. Evaluation of drug activity was most often done using a self-assessment questionnaire. During a 6-month open labeled study, Viagra was found to improve sexual function in 88% of those treated. This included frequency, firmness, and maintenance of an erection; frequency of orgasm; frequency and level of desire; frequency, satisfaction and enjoyment of sexual intercourse; and overall relationship satisfaction.

WARNINGS :

If you take any medicines that contain nitrates - either regularly or as needed - you should never take Viagra.