Female viagra hits dry spell

THE pharmaceutical industry's push to find a female version of Viagra has been full of letdowns.
Despite a decade of testing pills, patches, gels, nasal sprays and vaginal rings, there is still no approved drug for `female sexual dysfunction'.
More than a dozen drugs that reached late-stage testing have been abandoned, shelved or recycled for unrelated problems.
Market analysts still see a multibillion-dollar opportunity in female sexual complaints. And two drugs, LibiGel and Flibanserin, doggedly aspire to become the first to win the US Food and Drug Administration's (FDA) imprimatur.
But female sex disorders have turned out to be far more difficult to define and quantify, let alone fix, than erectile dysfunction.
With the 1998 approval of the first male impotence drug, entrepreneurs, researchers and many members of the fairer sex began lusting after a `pink' version.
Indeed, the first drugs to be tested in women were blood-vessel dilating agents that included Viagra and Cialis. The hope was that women would follow the classic male model of sexual response -- interest, arousal, orgasm.
They did not. Pfizer's research showed that genital blood flow increased in Viagra-treated women as they watched erotic videos, but the arousal did not make them desire sex.
The complexity of female response has kindled intense debate. How to distinguish normal from abnormal, physiological from psychological, discontent from debilitation?
In 2000, the FDA issued preliminary guidelines to help companies plan human studies of drugs for female sexual complaints. The guidelines, still not finalised, reflected the consensus that had emerged among sex experts at industry-supported conferences around that time.
The FDA said that although `the definition of FSD continues to evolve', it `currently' has four `components' -- decreased desire, decreased arousal, sexual pain and orgasm difficulties.
A woman with any one of these is dysfunctional, but only if she feels `personal distress' about it. Sex experts had added distress to diagnostic criteria for female sexual dysfunction in 1998, publishing a report in the Journal of Urology and the Journal of Sex and Marital Therapy.
The addition was a recognition that some women are happy with sexual inactivity, but it also foreshadowed the challenge of treating a largely subjective disorder.
Diminished libido, now called hypoactive sexual desire disorder, is what most drugs have focused on. Effectiveness is judged by how many `satisfactory sexual events' the woman reports during the study period, typically three to six months. Unlike an erection, a satisfactory event is whatever the woman thinks it is, from cuddling to coitus.
In study after study, placebos increased satisfying events almost or just as much as the actual drug.
Poor performance was an issue with Intrinsa, the Procter & Gamble testosterone patch for women who experience `surgical menopause' after having their ovaries removed.
In 2004, FDA advisers judged the product marginally effective, but rejected it because of a lack of safety data on long-term testosterone use.
Another contentious challenge for the industry has been quantifying -- critics would say exaggerating -- how many women suffer from sexual disorders.
The most widely cited prevalence estimate is taken from a national survey published in 1999 in the influential Journal of the American Medical Association. The study found that 43 per cent of American women aged 18 to 59 were sexually dysfunctional, compared with only 31 per cent of men. buy sildenafil online georgia


More recent surveys found that 3 to 12 per cent of women were sexually dysfunctional. buy cialis online south dakota