Viagra for low female libido suffers another setback

BioSante Pharmaceutical's stock plunged on the news that its "female Viagra" drug, LibiGel, was no more effective than a placebo in trials.

The topical formula is a testosterone gel for women. Other studies suggested that their formula worked (and testosterone cream is often prescribed "off label" to treat low sex drive in women), so the company expected safety concerns to be its biggest obstacle.

Although Pfizer, manufacturers of Viagra gave up several years ago on using sildenafil for women, there were reports last year that the company was looking into another drug - a compound called UK-414,495 - but then that seemed to hit a dead end as well.

Why is the formula for "female Viagra" so elusive? Maybe it's because comparing female and male sexual response is like comparing apples and oranges - or apples and bananas, if you prefer.

Viagra works on the hydraulics of the sexual anatomy - the blood vessels that engorge the genital tissue - not the mechanisms that generate libido or sexual desire.

The assumption is that's a given, that guys will have no problem with "wanting" to have sex. The issue is not desire, but ability to perform. Whereas with women, it's often the interest itself that needs to be stimulated.

Maybe that's why the placebo was just as effective as Viagra in the trials - they say the most important sexual organ is between your ears.

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