Viagra treats erectile dysfunction, not low libido. At a June hearing, the FDA's Hylton Joffe said there are no approved drugs for low libido in either women or men.
Flibanserin's manufacturer agrees that its medication works very differently than drugs that help men achieve erections.
For women, "it's not about blood flow," Whitehead said. "Desire is happening in the brain."
Unlike Viagra, which men take before sex, women would take flibanserin every day for the rest of their sex lives. Sprout has asked the FDA to approve flibanserin for premenopausal women whose lack of sex drive is not caused by a medical or mental health condition or by a medication, such as antidepressants. Flibanserin isn't designed to treat vaginal dryness that can make intercourse painful.
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Amanda Parrish, 51, said flibanserin helped restore her sex life.
Although she had a healthy sexy drive when she met her husband, her libido faded three or four years into their relationship, when she was about 46. Although she still enjoyed sex, she was no longer interested in initiating it. Their encounters fell from about six a month to two. Two weeks after she began taking flibanserin as part of a clinical trial, however, she found herself calling her husband to meet for a lunch-time rendezvous. While Parrish acknowledges that her experience is not the typical response to flibanserin, she says women should have the right to try it.
"I just got friskier again," said Parrish, from Brentwood, Tenn. "I even sent him a pantygram."
Parrish said flibanserin "is not a cure-all and not an aphrodisiac." At the same time, "most of us resist aging as much as we can," said Parrish, who has reached menopause. "Look at the market for eye creams. I'm going to fight aging every way I can."
Parrish notes that her husband, 58, began taking testosterone supplements to combat fatigue.
Critics of flibanserin reject the notion that the FDA needs to "even the score" on sexual health.
Supporters of flibanserin "have created this whole fiction about the FDA being sexist for not approving the drug," Fugh-Berman said in an interview. "It's not feminist to want a lower standard of safety for women."
Fugh-Berman noted that flibanserin can cause serious side effects: increased risk of fainting, low blood pressure, dizziness and sleepiness. Fainting can be especially dangerous if women lose consciousness while driving, she said. Taking flibanserin is as sedating as four alcoholic drinks, she said in her letter.
These risks are magnified if women drink alcohol or take common medications, such as antifungal, migraine medications and a long list of others, Fugh-Berman said.
The notion of telling women taking flibanserin to give up alcohol for the rest of their lives would be "both preposterous and doomed," said psychiatrist Leonore Tiefer, of the New York University School of Medicine, in a letter to the FDA co-signed with about 100 other health professionals. In her letter, she said therapy and education help many women with low libido.
Parrish said she's lucky that she has a husband willing to talk openly.
"There are a lot of women out there who are in bad relationships," Parrish said. A pill is "not going to make them want to have sex with a husband they aren't interested in."