Drug to increase women's sex drive wins FDA approval

For women with low sex drive, the Food and Drug Administration has approved a new EpiPen-like drug that promises to boost libido.

AMAG Pharmaceuticals says that the drug, bremelanotide, helps women with hyposexual desire disorder, or HSDD. The   FDA made the decision   on Friday.

The drug is somewhat similar to medications used to treat erectile dysfunction in men, in that they are meant to be used "on demand" — when a person wants to be sexually intimate.

But that's where the similarity stops.   Erectile dysfunction drugs   work by increasing blood flow to a man's genitals. Bremelanotide, on the other hand, works by targeting a woman's brain chemistry.

Put simply, experts say women with low sex drive tend to have higher levels of brain chemicals that increase sexual inhibition, and lower levels of chemicals that lead to sexual excitement.

Bremelanotide is said to work to balance out those chemical levels. "It's about trying to restore this balance and tipping it in the direction of excitation when a woman wants it," said Dr. Julie Krop, chief medical officer for AMAG Pharmaceuticals.

Women are more complex than men sexually. It’s hormonal, but it’s not just hormonal.

But some sexual health experts argue that a woman's libido is much more than simple brain chemistry.

"Women are more complex than men sexually. It’s hormonal, but it’s not just hormonal," said Dr. Virginia Sadock, a clinical professor and director of human sexuality training in the Department of Psychiatry at NYU Langone.

Still, Sadock is not ready to dismiss bremelanotide entirely. "It’s obviously something women are interested in, and it's worth pursuing. But is it a miracle drug? Unlikely," Sadock told NBC News.

Measuring benefit

The drug, which will be marketed under the brand name Vyleesi, is an auto-injector, and is administered just like an EpiPen. The shot is self-administered to the abdomen or thigh at least 45 minutes before sexual activity.

In company-funded studies of more than 1,200 women identified as having HSDD, about 60 percent said they benefited from the drug, compared to about 35 percent who received a placebo.

But measuring "benefit" can get murky.

"When you're looking at things like desire, there's no blood test, no CT scan, no way to measure these things other than what's called a patient-reported outcome," Krop said. This means asking women how they're thinking or feeling, similar to how doctors study drugs for depression or anxiety.

Doctors say it's desirable for any drug meant to treat low sex drive to have modest benefits. "The women who come into my office are in long-term relationships. They’re not looking to all of a sudden have tremendous sexual desire, and to have sex every day," said Dr. Sheryl Kingsberg, chief of behavioral medicine at University Hospitals Cleveland Medical Center. Kingsberg was a primary investigator in the studies of bremelanotide, and is a paid consultant for the drug company.

"They want to restore what they had," she said.

Side effects were minimal, according to AMAG. Some women reported that the injection made them feel nauseated. Eight percent of those study participants dropped out because of it.

The drug is only recommended for pre-menopausal women because it has not been studied in post-menopausal women.

What is HSDD?

AMAG says a woman would qualify for a diagnosis of HSDD if she were distressed by her persistent lack of desire for sexual activity. She, along with a physician, would have to rule out every other possible explanation for that low sex drive, such as relationship problems, stress,   depression   or fatigue.

"For these women to have had good desire, and then to have lost it, for no situational reasons, it’s very distressing. And it has an impact on their lives well beyond the bedroom," said Kingsberg.

Low libido is multifactorial.

AMAG estimates as many as one in 10 women has HSDD. However, those who treat women's sexual health problems say the true numbers are much lower.

"Low libido is multifactorial," said Dr. Lauren Streicher, medical director of the Northwestern Medicine Center for Sexual Medicine and Menopause. She goes into a "deep dive" of the personal and medical history all of the women who seek her help.

"We have to address all of those other things that may be contributing," Streicher, who wasn't involved with work on the new drug, said. "Maybe they have a history of trauma. Maybe they're on an antidepressant that's killed their sex drive."

"Quite frankly, it's rarely just one thing."

But Streicher also welcomed possible FDA approval of the drug, which she said looks like will help women who truly need it.

"It's not that HSDD is not real. It's real. It's a question of what precipitated the HSDD and what are all of our options in terms of making it go away," Streicher said.

Some experts compare HSDD treatment to that of depression or   anxiety . Some patients do well with psychotherapy, others do well on medication, while others might need a combination approach.

The only other FDA-approved drug meant to treat low sex drive in women is called   Addyi . But Addyi never really caught on mainly because it comes with a warning that women should not drink alcohol while taking the pill, which must be taken daily.

When Addyi was   green-lit by the FDA in 2015 , two distinct camps emerged: those who insisted that, because men had multiple drug options to enhance their sex lives, women were long overdue, and those who strongly questioned both the existence of HSDD and whether the pharmaceutical industry had any business dabbling in sexual desire.

Four years later, those camps remain, but appear to have met in somewhat of a middle ground. Generally, experts agree that it's perfectly normal for libido to fluctuate throughout women's lives, and that it's not necessarily a medical problem. They also concede that there does appear to be a small number of women who truly perceive that they suffer from low sex drive, and need far more than, say, counseling to rekindle the desire they once enjoyed.

"There is a chorus of women who are naysayers, and I feel that is a disservice to the interests of women," said Sally Greenberg, executive director of the National Consumers League, a nonprofit that advocates for consumers.

"To me, it means you are not listening to women."