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Viagra
for women
Viagra for Women
In 2004, Pfizer Inc., the makers of the Viagra
pill—introduced to improve men’s sexual health and
functioning—announced that they would be abandoning eight years of
previous research conducted in an attempt to develop a drug similar
to Viagra to improve female libido and sexual health. Other products
designed to improve sexual health in women are available.
In its efforts
to develop a new antidepressant, a German drugmaker has
stumbled upon a substance that increases female arousal
.
German drugmaker Boehringer Ingelheim didn't set out to
create a Viagra-like drug for women. The company was
simply trying to develop a fast-acting antidepressant,
one that patients would respond to in a matter of days,
not weeks as in most current treatments. By the late
1990s the company had developed a molecule called
flibanserin that seemed to relieve stress in rats. But
like many promising drugs, it flopped in human trials.
Says Dr. Lutz Hilbrich, the company's executive director
of general medicine: "We did not see the effect we were
expecting."
But what they did see surprised them. Like all companies working on
antidepressants, Boehringer surveyed patients in its clinical trial
to assess dampening of libido, a well-established side
effect. Far from complaining about a drop
in sexual desire and arousal, many of the women in the trial
reported a surge.
The men had no such response—and neither group showed any
improvement in mood. "It is an interesting drug," says Dr. André T.
Guay, director of the Center for Sexual Function at the Lahey Clinic
Northshore, Peabody, Mass., and assistant professor at Harvard
Medical School. "These things come about in strange ways."
Tough Road
It's hard to escape a comparison with Viagra. In the mid-1990s,
researchers at Pfizer Inc. (PFE) were testing an experimental drug
for angina, or chest pain, and were stunned to discover the
stimulating side effect.
Since Viagra hit the market in 1998, drugmakers have been searching for the female equivalent. Procter &
Gamble (PG), for instance, is trying to win Food & Drug
Administration approval for a testosterone patch that produces
modest effects in women, and others are testing topical creams and
nasal sprays.
"It is a very large potential market for drug companies," says
Cleveland Clinic urologist Dr. Jeffrey S. Palmer. Annual sales of
erectile-dysfunction drugs for men have already topped $2 billion.
Boehringer has placed a big bet on flibanserin. The company has
launched four major clinical trials, involving 5,000 women in 220
locations, with the goal of applying for FDA approval in 2009.
Drug development is never easy, however, and flibanserin faces a
tougher road than usual. There's an ongoing controversy about
whether or not a female analog to erectile dysfunction even exists.
In October, the Endocrine Society issued guidelines cautioning that
sexual dysfunction, if it exists at all, may have nothing to do with
any "defect in the woman's physical sexual response system."
Not So Fast
The Society concluded that the most common current treatment,
testosterone, should not be recommended. The big question: If a
woman doesn't experience physical desire, is it a medical condition,
like inadequate blood flow in men, or something purely
psychological? "Maybe she just doesn't like the guy she's with,"
says Washington (D.C.) psychotherapist David Waldman.
Plus, it's not yet clear exactly how flibanserin works. Company
researchers have figured out that it hits several circuits in the
brain that are linked to feelings and pleasure. One of those
circuits apparently helps control sexual desire and arousal,
although the effects are not immediate. "This is not something that
can be taken on a Friday for the weekend," says Boehringer Ingelheim
spokesman Mark R. Vincent. "There is a gradual increase in sexual
desire over a six- to eight-week period."
Pinning down the mechanism is especially critical, in this case,
because the FDA views drugs that affect the complicated central
nervous system with extra caution. Regulators are especially wary of
drugs that might be used widely as a lifestyle choice rather than
just to treat disease. "It is difficult for drugs for the central
nervous system to be approved for something as banal as sexual
function," says Lahey Clinic's Guay.
Doctors investigating new treatments for women retort that men's
problems were also seen as largely psychological until Viagra came
along, and that loss of sexual desire isn't trivial to many of those
who experience it. Indeed, Boehringer says it's having no trouble
recruiting women for the trial, some of whom travel long distances
for the chance to try the drug. Even if flibanserin doesn't pan out,
understanding how it boosts desire should point the way to better
versions—and perhaps give women a choice about whether or not to pop
a little pill.
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