Other than the fact that they both originated to treat other conditions, Viagra (which began as a cardiovascular drug) and flibanserin have little in common.

Viagra proved to be helpful to men who were interested in having sex, but were suffering from erectile dysfunction. Flibanserin, on the other hand, is meant to help pre-menopausal women who suffer from a lack of interest in sex.

"Flibanserin was a poor anti-depressant," lead researcher Prof. John Thorp told the European Society for Sexual Medicine at a congress earlier this week in Lyon, France. "However, astute observers noted that it increased libido in laboratory animals and human subjects. So, we conducted multiple clinical trials."

In trials held in Canada, Europe and the United States, some 2,000 pre-menopausal women were given flibanserin or a placebo for 24 weeks. Analysis showed that women who took 100 milligrams of the drug each day noted "significant improvement" in the number of "satisfactory sexual encounters" they had, and their level of sexual desire.

"It's essentially a Viagra-like drug for women in that diminished desire or libido is the most common feminine sexual problem, like erectile dysfunction is in men," Thorp said.

Possible launch within three years

Flibanserin is currently an investigational drug, although Boehringer CEO Andreas Barner told German magazine Wirtschafts Woche in July that it could come on the market in two to three years.

A spokesperson for Boehringer, the second-largest drug maker in Germany after Bayer, said the company was preparing regulatory filings in the US and subsequently for Europe and other markets. It claims that Hypoactive Sexual Desire Disorder (HSDD) is an under-recognized women's sexual health condition that affects one in 10 women in the US alone.

But for many critics, HSDD is a made-up condition that mainly benefits the pharmaceuticals industry. Sex therapist and activist Leonore Tiefer, for example, has long written about "disease-mongering" on the part of drug makers. She and others have said flibanserin is part of a trend to medicalize normal sexual responses that are the result of non-medical factors, such as stress, relationship problems, poor body image or, quite simply, overtiredness that affects women juggling a job, childcare, and housework.

A spokeswoman from Boehringer Ingelheim, however, urged critics to "listen to women who have this problem."

"There is a desperate need," the spokeswoman recently told the Berlin-based Tagesspiegel newspaper. "This is not a made-up illness, it's a real problem."

dc/Reuters/afp

Editor: Sean Sinico