By Rita Rubin
WebMD Health News
Reviewed by Michael W. Smith, MD
Aug. 18, 2015 -- After two rejections and years of back-and-forth over its real benefits, the FDA on Tuesday approved the first drug designed to help women distressed about their lack of libido.
Flibanserin, which will be sold as Addyi, has a checkered regulatory history. In 2009, an FDA advisory committee unanimously voted against approval because pivotal clinical trials failed to show that it was significantly better than a placebo in improving women's sexual desire. The FDA followed the panel's advice and turned down the drug in 2010.
Drugmaker Sprout Pharmaceuticals reapplied to the FDA in 2013 with results from a new clinical trial, but the agency again rejected it, spurring the company to help launch a campaign called "Even the Score" to press for approval.
Critics had charged the FDA with gender bias for failing to approve any drugs to improve women's sex drive, a charge that divided women's and health organizations.
An "Even the Score" petition urging the FDA to approve a drug for women with low libido collected more than 60,000 signatures. Some members of Congress also got involved, urging the FDA earlier this year to approve the drug.
But not everyone jumped on the bandwagon.
"I'm a pro-sex feminist, but I believe that advocating for women's health means finding solutions for women's sexual problems that are safe and effective," Cindy Pearson, executive director of the National Women's Health Network, wrote June 8 in a Washington Post op-ed piece. "That hasn't happened. Not yet."
Pearson's piece ran 4 days after an FDA advisory panel voted 18-6 in favor of recommending approval of flibanserin.
In a statement Tuesday, the FDA noted "a potentially serious interaction" when combining Addyi with alcohol, and said women who drink alcohol should not take it. The drug can cause low blood pressure and fainting, the agency says, and those risks are increased when Addyi is combined with alcohol or certain medicines. The drug will only be available through doctors and pharmacies who undergo training on the risks, the agency says, and will carry a so-called "boxed warning."
WebMD asked several experts -- including a doctor who sat on the most recent FDA advisory committee and a clinical psychologist involved in testing Addyi -- about the new drug.
Q. Who is a candidate for Addyi?
Addyi is the first drug approved for the treatment of premenopausal women with hypoactive sexual desire disorder (HSDD).
The disorder is the most commonly reported form of female sexual dysfunction, affecting 1 in 10 U.S. women. Simply lacking desire does not mean a woman has HSDD. She also has to feel distressed about it.
"I think it's hard to understand these women's experience of having low sexual desire," says Stanley Althof, PhD, executive director of the Center for Marital and Sexual Health of South Florida and a Sprout consultant who worked on the testing of Addyi before its approval. "It's very painful for them. They often come in desperate, thinking their marriage or their relationship is at risk."
In the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), considered to be psychiatry's "bible," HSDD has been combined with female sexual arousal disorder to form the diagnosis of female sexual interest/arousal disorder.
Some doctors might consider prescribing Addyi to women who have trouble achieving an orgasm, Althof says, "but it's not likely to be successful."
Q. Addyi has been called the "female Viagra," but are the drugs really that similar?
"Probably the most dangerous thing people can do when talking about this drug is to call it 'female Viagra,'" says Walid Gellad, MD, who sat on the latest FDA advisory committee and voted in favor of approving flibanserin. "It's completely different." Gellad is an assistant professor of medicine and of health policy and management at the University of Pittsburgh.
Althof agrees. "It's clever, it's cute, but it's just factually incorrect," he says. "You're really looking at affecting brain chemistry vs. blood flow."
Viagra and other drugs for erectile dysfunction increase blood flow to the penis, but they don't increase men's libido. Addyi works on brain chemistry. It was originally tested as an antidepressant in men and women. It failed as an antidepressant, but women in tests of the drug reported experiencing more sexual interest, which led to it being studied as a sexual disorder treatment, Althof says.
In addition, while Viagra and other erectile dysfunction drugs are taken as needed, Addyi is taken daily, according to Sprout Pharmaceuticals.
Q. How effective is it?
"It's effective. It's just not very effective," Gellad says.
According to data submitted in 2013, women who took flibanserin for 24 weeks reported having an average of one more satisfying sexual event every 2 months than a comparison group of women taking a sugar pill.
That might not sound like much, but for women with the disorder, that's "very meaningful," Althof says.
At the advisory committee meeting, Sprout said it plans to recommend that women stop taking Addyi if they don't feel more desire after 12 weeks, Gellad says. But because of the strong placebo effect seen in the clinical trials, "it's highly unlikely that people will have no effect from this."
"It doesn't treat all sexual dysfunction, it won't help all women with sexual problems, but it will have a role in the therapy," says Holly Thacker, MD, director of the Cleveland Clinic Center for Specialized Women's Health, in a statement.
Q. What are the side effects?
Besides the side effects when Addyi is combined with alcohol, the FDA also raised concerns about dizziness, fatigue, and fainting when the drug is taken with hormonal contraceptives. There is the potential for other side effects as well, the agency said.
Tests of the drug enrolled generally healthy women who weren't taking other medications, such as sleep aids, that could worsen the side effects, Gellad says. At the advisory committee meeting, he says, Sprout said it planned to limit the number of prescribers by taking steps such as not distributing samples for the first 1 or 2 years. The company also said Tuesday it would not advertise on television or radio for 18 months.
"If this medication can really help some women ... have it on the market in as safe a manner as possible," Gellad says. "This drug should be restricted in whatever way can be done to ensure that only the people who really will benefit will get it."
Q. How much will the drug cost, and will insurance cover it?
The drug will be available beginning Oct. 17, Sprout Pharmaceuticals says in a statement.
The drug's price has not yet been determined, but will likely be equivalent to the monthly cost of erectile dysfunction drugs for men, Cohen says. It's expected the drug will be covered by insurance with a copay of about $30 to $75 a month.
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