jenk

After eight years of work and tests involving 3,000 women, Pfizer Inc. announced yesterday that it was abandoning its effort to prove that the impotence drug Viagra improves sexual function in women. [...] For men, arousal almost always leads to desire. So by improving a man's ability to have erections, Viagra measurably affects his sexual function. But arousal and desire are often disconnected in women, the researchers found, to their consternation.

Although Viagra can indeed create the outward signs of arousal in many women, that seems to have little effect on a woman's willingness, or desire, to have sex, the researchers said. [...] Women who once had normal sexual function but then suddenly lost all desire - often as a result of taking antidepressants - can be helped by Viagra, he said. Women who have always had low libido levels are unaffected by Viagra, he said. [...]

Pfizer once had great hopes for its clinical program testing Viagra in women. Viagra works by blocking an enzyme that normally inhibits blood flow, causing penile tissue to swell. That enzyme is found in great quantities in the penis and is also found in the pelvic region of women.

In one early clinical trial, researchers gave six women Viagra and six others a placebo, sat them in front of erotic videos and used a pelvic probe to measure any change in genital blood flow. The sex organs of women given Viagra were more engorged than those given placebos. The program seemed to be succeeding, Dr. Tiefer said.

But a larger trial that included a questionnaire found that although Viagra was associated with greater pelvic blood flow, the women experiencing this effect did not feel any more aroused, Dr. Boolel said.

Pfizer researchers spent years trying to find some well-defined group of women for whom increased pelvic blood flow and desire could be linked. They failed, he said. - New York Times article