The U.S. approval of a pill to treat low libido in women has whipped up a whirlwind of debate and raised questions about whether the so-called female Viagra addresses the real reasons for lack of sexual desire.

The U.S. Food and Drug Administration last week approved flibanserin, to be sold under the name Addyi starting in October, for the treatment of hypoactive sexual desire disorder (HSDD) among premenopausal women — some two decades after Viagra was approved for the treatment of male erectile dysfunction. 

Sprout Pharmaceuticals pitched flibanserin as a drug that would finally give women with sexual dysfunction similar treatment options to men and bused dozens of women to FDA hearings in Maryland to attest to its benefits and plead for its approval in what some saw as a heavy-handed and misleading public relations campaign.

The FDA gave flibanserin the OK after twice rejecting it and despite concerns about its risks and modest efficacy because it said women suffering distress from low libido have an "unmet medical need." Days after it did, Canadian pharmaceutical company Valeant offered to buy Sprout for $1 billion US and said it will apply to get flibanserin approved in Canada and other countries.

Taking pill vs. talking it through

Although often likened to Viagra, flibanserin was created as an antidepressant and works on the brain while erectile dysfunction medications stimulate blood flow to the penis. It must be taken daily — unlike Viagra, which is taken up to four hours before sex.

Critics argue it's an ineffectual pharmacological solution for a problem better treated with relationship counselling, sex therapy and behavioural changes.

"Their suffering is real, but the women who testified had a lot of different stories, and some of those stories were very good reasons for having low libido, including having six children, having a one-year-old, having had breast cancer treatment …," says Adriane Fugh-Berman, associate professor of pharmacology and physiology at Georgetown University in Washington, D.C., and director of PharmedOut, a pharmaceutical marketing watchdog group.

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A few days after the new sexual dysfunction drug from Sprout Pharmaceuticals was approved for sale in the U.S., Canadian pharmaceutical company Valeant offered to buy it for $1 billion US. (Allen G. Breed/Associated Press)

Fugh-Berman's view is echoed by Cynthia Graham, a Canadian psychologist currently working as a professor of sexual and reproductive health at the University of Southampton and a research fellow at the Kinsey Institute at Indiana University.

"We know that a lot of sexual problems are related to relationship issues, stress, contextual issues. … For these, I don't think medication is the answer," she said.

Most people are "inhibited and tongue tied" when it comes to sex, says sex therapist Leonore Tiefer. She tries to help patients unravel the relationship and personal issues at the root of their sexual problems, but that kind of work is much messier than popping a pill, she says.

"In a society where it's your fault if you don't get sex right, and you have to have a lot of it and you have to do it right but nobody teaches you how ... you're looking for a way to excuse yourself from your problems, and biology offers that excuse," said Tiefer, a clinical associate professor of psychiatry at New York University School of Medicine.

Desire, arousal intertwined

Tiefer, who campaigned against approval of flibanserin, felt most members of the expert committee advising the FDA were not familiar enough with the latest research on sexual dysfunction and too swayed by patients' emotional testimony. 

Scientific thinking about sexual desire has changed, and, in fact, HSDD no longer appears in the Diagnostic and Statistical Manual of Mental Disorders, widely used to diagnose patients but also to assess insurance claims.

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Mistakenly dubbed the 'female Viagra,' the male drug that improves blood flow to address erectile dysfunction, flibanserin targets the brain. Some women on flibanserin reported a greater number of 'satisfying sexual events' and less distress about their low libido. (Mark Blinch/Reuters)

It's been reclassified as female sexual interest/arousal disorder because scientists don't view desire and arousal as separable any more, says Graham.

Absence of sexual thoughts or fantasies used to be a key part of diagnosing a desire disorder in women, but "there's a lot of research now that suggests not all women even report fantasies," she said. "Some fantasize a lot, and others say they don't fantasize but they feel very sexually satisfied."

Desire is also no longer thought of as "this spontaneous, horny thing that just comes out of nowhere, which is pretty much how HSDD views it," Tiefer said.

'Compelling testimony' about pill's impact

Tiefer and Graham fear flibanserin feeds into the unrealistic expectations people have about sex.

"The approval of this drug is going to encourage that idea that we should all always have the same level of sexual desire, that it should not really be affected by having kids, by stress, by fatigue, by relationship problems," Graham said.

Clinical trial subjects who were on flibanserin reported having only an average of 0.5 to one more "satisfying sexual events" a month compared with the placebo group and a modest alleviation of distress and increase in desire. Eight to 13 per cent were "much improved" on at least one of the three measures.

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The approval of flibanserin comes with strict restrictions on who can prescribe and dispense it. The drug packaging will carry a boxed warning highlighting potential side effects and drug interactions, and doctors and pharmacists will have to be specially certified before giving the drug to patients. (Gary Cameron/Reuters)

"Most committee members felt these effects were small," said Caleb Alexander, co-director of the Center for Drug Safety and Effectiveness at Johns Hopkins Bloomberg School of Public Health, and one of six committee members (out of 24) to vote against the drug. "On the other hand, we were hearing from individuals who provided compelling testimony that the product made an important difference in their lives." 

Even those who recommended approval of the drug expressed reservations, because of its modest benefits and serious side-effects, which include low blood pressure, drowsiness and fainting.

"[I] believe that it should be used by almost no one," said Walid Gellad, associate professor of medicine at the University of Pittsburgh and co-director of the Center for Pharmaceutical Policy and Prescribing.

Gellad says he has no regrets about recommending approval of flibanserin but advises women to "try everything" before they use it.