canada_winnipeg_man replied: "Viagra, whose active ingredient is sildenafil, was launched in 1998 for use in men with erectile dysfunction (E.D.). Men have problems with erections for a variety of psychological and physiological reasons. Only a health care provider can determine if Viagra is appropriate for their individual situation. Viagra works by allowing increased blood flow to the penis, thus causing an erection. Some researchers theorize that sildenafil may have a similar effect in women, allowing the erectile tissue of the clitoris to engorge with blood. Tests on sildenafil's effects on women have been conducted by Pfizer (the company that developed Viagra), but the results were inconclusive. Other companies have tried to develop a female equivalent, but to no avail. While there is no form of sildenafil that has received approval for women from the U.S. Food and Drug Administration (FDA), some health care providers have reported prescribing Viagra to women who had physiological sexual dysfunctions. They do not recommend Viagra for women who have psychological sexual dysfunctions. Men who take Viagra by prescription risk side effects, such as skin flush, headaches, indigestion, and muscle pain. Some men report that high doses cause visual disturbances, including seeing a blue "haze" surrounding objects. Priapism, a prolonged, often painful erection, has also been reported. Serious drug interactions can occur. Viagra users who take heart medications that include nitrates risk dangerously low blood pressure. (Illegal stimulants, such as ecstasy and cocaine, are often cut with other drugs containing nitrates.) Because sildenafil has not received FDA approval for use by women, side effects in women are not known. Women could experience side effects similar to men, but they could also experience others that could potentially be more serious. Mail-order and Internet pharmacies have tried to cash in on Viagra's popularity. Since many of these pharmacies and the drugs they sell are not regulated by the FDA, customers run the risk of receiving low quality or counterfeit items or drugs that may cause the user great harm. Men using Viagra need to have it prescribed by a health care provider and dispensed by a licensed pharmacist. Women who obtain the drug from their partner, a mail-order pharmacy, or the Internet run the same risks, including the known and unknown side effects mentioned above. The realm of human sexuality is only limited by our imagination. Since you and your partner are comfortable discussing your likes and dislikes, encourage your partner to experiment with other safer methods of arousal. Pleasuring and enjoying each other instead will be more fun than worrying about potential negative side effects."