October 22, 2018
Flibanserin, the \

Flibanserin, the 'Viagra for Women'

by Berkeley Wellness  

Tami Rowen, MD, MS, is a gynecologist and clinical instructor at the University of California, San Francisco. She provides care for women with sexual health concerns, among other health problems, and has participated in several national and international studies on women’s sexual health.

We spoke with Dr. Rowen about the new drug flibanserin (Addyi), touted as "Viagra for women." The Food and Drug Administration approved flibanserin on Aug. 18, 2015, to treat lack of sexual desire in women before menopause—a condition called hypoactive sexual desire disorder.

Q: What is this new drug, flibanserin?

Flibanserin is an antidepressant that failed to help depression in clinical trials, but was noted to have improved sexual health outcomes. It’s not uncommon for a drug to be developed for one purpose, then approved for another. Sildenafil (Viagra) was originally developed to lower blood pressure, but failed those trials. The benefit of both of these drugs was discovered by accident. However, flibanserin has now been studied for its effects on sexual health for nearly a decade.

Q: How does this drug work to boost a woman’s libido?

Researchers think that flibanserin restores some of the chemical imbalances that affect sexual desire disorders. Most people have heard of antidepressants known as selective serotonin reuptake inhibitors, like fluoxetine (Prozac). SSRIs can have negative sexual side effects, such as reduced libido or erectile dysfunction. This suggests that serotonin plays an important role in sexual desire and excitation. Flibanserin affects serotonin but in a different way than SSRIs. It stimulates one type of receptor while blocking another, and it also increases dopamine in the body. Dopamine is known to have positive effects on sexual health.

Q: What are flibanserin’s benefits and drawbacks?

This is the first medication approved to treat sexual desire disorders, and that’s a benefit for some women. While many people think that desire is more psychosocial than biological, there are clear biological processes that affect sexual desire and function. Flibanserin was shown to have a modest improvement over placebo in increasing desire. Women taking the drug had up to two more satisfying sexual events (SSEs) each month, compared to the placebo’s increase of one more SSE a month.

It is important to note that it is very hard to overcome the placebo effect when studying drugs—people often improve on placebo alone. The controversy over flibanserin focuses on the degree of benefit. Is one more sexually satisfying event each month enough of a benefit? For many women, this is a significant increase and should not be discounted, given how important sex can be in a relationship. Overall desire scores also increased in the most recent trials, which is very important to many women.

The drawbacks are that there are adverse effects with this medication, as there are with all medications. The major adverse effects are dizziness and drowsiness, which can affect about 10 percent to 15 percent women taking the medication. This is not significantly different from the widely prescribed SSRI antidepressants. We don’t yet have long-term data on other potential risks, including cancer. It should be pointed out, however, that Viagra was approved with six months of safety data. Most studies on flibanserin have one to two years of safety data.

The other drawback is that people are concerned this drug will simplify the complex factors that affect women's sexual health. Many people feel that this is just a ploy by pharmaceutical companies to cash in on a problem that is widespread, and cannot be treated pharmacologically.

Q: Why is flibanserin such big news?

Up to 40 percent of women report having sexual problems, and about 12 percent find the problems very bothersome. This equates to millions of women who suffer from female sexual dysfunction, the most common being hypoactive sexual desire.

Women are still in the shadows when it comes to talking about sexual dysfunction. They’ve been told for years that their only options are expensive therapies, including psychotherapy, hormones, and supplements. The FDA’s standard of approval for drugs to treat sexual dysfunction in women is significantly higher than for those to treat men's sexual health concerns.

Just like Viagra opened the door for men to talk about sexual health, the hope is that flibanserin will allow women to discuss this often highly distressing problem—and have an option for treatment. This is an important development for women and for those of us who treat them.

This opinion does not necessarily reflect the views of the UC Berkeley School of Public Health or of the editorial board of BerkeleyWellness.com.