What can you tell me about the drug Viagra and the latest treatment for impotence?
Erectile dysfunction can stem from many causes and can range from complete inability to achieve an erection at all, to inability to maintain an erection long enough to have satisfactory intercourse. Many men have a problem with erectile function at some time in their lives. The causes include interference in the nerve supply to the penis, usually from trauma or surgery; interference with the blood supply to the penis, usually from diabetes; low levels of testosterone, the male sex hormone; reaction to drugs including alcohol; and psychological causes.
The treatments available before the approval of Viagra were penile implants, various mechanical methods of producing and maintaining an erection, the injection of a drug into the penis itself, and the recently approved Muse, a tablet that is inserted into the tip of the penis. Although both the injection and Muse produce good erections in a large percentage of men, both techniques require doing something slightly unpleasant and interrupting the intimacy of the moment.
Viagra, in contrast, is taken about one hour before one anticipates having sex. It enhances and prolongs the chemical changes in the penis that come with sexual arousal and that induce the erection. It will not induce an erection unless the man becomes sexually stimulated. If he does not, the pill has no effect. Viagra works by inhibiting the degradation of nitric oxide, a ubiquitous chemical in the body that is important in maintaining an erection. Viagra can cause a severe drop in the blood pressure of someone who is taking a nitrate medication for heart disease, such as nitroglycerine, Imdur, Ismo, Nitro-Dur and others. It does not cause side effects in someone taking medications for high blood pressure if they do not contain nitrates. Any man taking medication for heart disease should clearly ask his doctor if Viagra is safe for him before trying it.
Like the other techniques, Viagra requires that there be an adequate blood supply to the penis, without which pressure cannot build up to produce the erection. In the studies leading up to the FDA approval, about 70 to 80 percent of men developed erections if sexually stimulated after taking the drug. Side effects were minor, consisting of headache, flushing, indigestion, nasal congestion, and in about 3 percent of men, a mild bluish tinge to their vision that lasted no more than a few hours.
The drug is approved to be taken only once per day, and the company stresses that it should not be taken repeatedly to try to produce a sexual marathon. The cost to the consumer is about $9 to 10 per dose, making it affordable to most men.
Since its introduction, widespread use of Viagra has not resulted in the identification of any serious side effects other than the interaction with nitrates that I mentioned above. The approval of Viagra, the first effective oral treatment for erectile dysfunction, represents a real turning point in the treatment of this troublesome, and often hidden, condition. Let’s hope that this success will also stimulate research into women’s sexual dysfunction issues as well.