There was a time when a man and a woman would have sex several times a week without the use of Erectile Dysfunction medication, such as Viagra

But now, the black negligee used to entice her man originaly, has been stuffed in the back of a drawer and a box of Erectile Dysfunction tabklets is reached fopr.

For over a decade, since the FDA approved Viagra for Erectile Dysfunction in men, drug companies including Pfizer have been searching for the female version of the little blue pill.

But what ails them — a psychiatric condition known as hypoactive sexual desire disorder (HSDD), defined as a distressing lack of sexual desire, absent other medical conditions — has been notoriously difficult to pin down.

That doesn't keep drug makers like Pfizer from trying to develop a treatment for the female version of Erectile Dysfunction.

At a European conference for Erectile Dysfunction and sexual medicine on Monday, a German pharmaceutical company presented results from a pivotal phase III clinical trial in North America and announced that it had found a drug that works. "We saw an increase in sexually satisfying events, an increase in desire and a decrease in distress. When we look at this against a backdrop of a common and distressing problem that affects 1 of 10 women and for which no treatment exists, well, we are feeling very positive," said Michael Sand, director of clinical research for Boehringer Ingelheim, which originally developed the drug, flibanserin, in the 1990s as an antidepressant. (The drug proved not to work for depression.)

Whether or not the FDA approves flibanserin to treat women's libidos, the German company's trial results have reignited a decade-long debate over the merit of the HSDD diagnosis — the most commonly diagnosed female sexual dysfunction — which some psychologists say is a made-up condition, promoted precisely for the service of moments like this: a drug-company rep at a conference on sex declaring that a treatment has been discovered.

Attempting to treat low libido with a pill similar to the Erectile Dysfunction drug, Viagra, ignores the fact that many women's level of desire is deeply affected by everyday life stress and interpersonal relationships.

Add to that a cultural milieu that at once promotes shame and ignorance about women's sexuality while wildly inflating their expectations for sex. In many cases, says Norsigian, the proper solution to a lack of sexual desire would involve a number of non-drug approaches, such as therapy, mind-body techniques and getting partners involved in the solution.

"That could be equally successful while at the same time not exposing women to the long-term adverse effects of drugs like the Erectile Dysfunction treatment Viagra," says Norsigian, who suggests testing drugs like flibanserin against drug-free therapies.

"Moreover, the non-medication approaches often address root causes for lack of libido and thus reflect a prevention approach that is usually much wiser.

Yes, women are complex and so are their libidos. Which is why the quest to treat HSDD has been so fraught. It is far more difficult than, for instance, treating men's complaints about Erectile Dysfunction with Viagra.

Viagra works for men suffering with Erectile Dysfunction bysimply by increasing blood flow to the penis and producing an erection.

Beyond the many and varied psychological roots of the problem, there is still much that is not known about the biological processes governing women's sexual desire. One of researchers' best guesses so far is that women with HSDD have low levels of testosterone. Indeed, the condition affects mainly postmenopausal women or those who have had their ovaries surgically removed, which leads to a drop in sex hormones — namely testosterone.

Many American women already use testosterone treatments off-label to treat their low libidos, and doctors attest that they work. But past efforts by Erectile Dysfunction drugmakers such as Pfizer to get such treatments approved by the FDA specifically for HSDD have been blocked for safety concerns.

Intrinsa, a testosterone patch manufactured by Procter & Gamble, is used to treat female sexual dysfunction in postmenopausal women in Europe, but after being tested in women in the U.S., the FDA rejected P&G's fast-track request for approval, requesting more long-term safety data. Early trials of the experimental compound PT-141, a nasally inhaled drug that affects brain receptors for the hormone melanocortin, which plays a role in sexual arousal, raised concerns about its effect on blood pressure. A somewhat more promising contender is LibiGel, a testosterone gel made by Illinois-based BioSante Pharmaceuticals, which is in phase III clinical trials.

Flibanserin, however, does not act on hormones, and the new data suggest that it works in premenopausal women. "We don't yet understand the pathways. What we think is that in women with HSDD, there is likely an imbalance of serotonin, and that flibanserin is balancing the imbalance in these neurotransmitters," Sand says.

The flibanserin findings are based on the study of 1,378 premenopausal women who had been in a monogamous relationship for 10 years on average. The women were randomly assigned to take 100 mg of flibanserin or a placebo daily and to record daily whether they had sex and whether it was satisfying. The women were screened for depression and other medical conditions, and all had a diagnosis of HSDD.

Women in the flibanserin group self-reported 2.8 sexually satisfying events in the four-week baseline period; in the final four weeks of the 24-week study period, those women reported 4.5 sexually satisfying events, a more than 50% increase. Women in the placebo group reported an increase from 2.7 events to 3.7. The difference in effect between flibanserin and the placebo — about 0.8 sexually satisfying events — was statistically significant, the drug company said, and the side effects from the drug, which included dizziness and fatigue, among others, were mild to moderate and transient.

It remains to be seen whether 0.8 more bouts of satisfying sex is enough to win FDA approval. In the meantime, however, Boehringer Ingelheim insists that the results shore up evidence for the neurobiological basis for HSDD.

But critics of such treatments for Erectile Dysfunction worry that while a pill could potentially improve sex for some women, others may be more harmed than helped. Debby Herbenick, a sex educator and researcher at Indiana University's Kinsey Institute, does not deny that there is a biological cause of low libido. But she raises another kind of concern about drugs like flibanserin: What if they work? "[The problem] is far more complex than not desiring sex. What we really have is a group of women who wonder why they don't desire their long-term partner the way they used to," Herbenick points out. "What happens if you suddenly do have desire, but it's not for the person you hoped?"

That, of course, is not a side effect that was measured in any of the drug trials involving female Erectile Dysfunction — including those on flibanserin — and not one that will be weighed by the FDA.

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