Recently, Sprout Pharmaceuticals attained approval from the Federal Drug Administration (FDA) to sell their female sexual dysfunction drug Flibanserin–to be marketed as Addyi.
Technically, Addyi is not for treating inability to be aroused or to achieve orgasm, but instead it is specifically for Hypoactive Sexual Desire Disorder (HSDD). Yes, this is apparently a thing and–I was shocked to discover–the most common form of female sexual dysfunction! HSDD is characterized by a persistent or recurrent absence of sexual desire that is often associated with stress or interpersonal difficulties. In a large cohort study with more than 30,000 women, 12% scored low enough on a scale of sexual desire to be diagnosed with HSDD (Obstet. Gynnecol. 2008 Nov. 112(5):970).
Before going into how Addyi works, there’s a really important distinction to be clear about and that’s the difference between sexual desire and arousal. Of course they are linked: desire to have sex may lead to arousal and if you’re aroused you probably have the desire to have sex. But that does not mean that they are the same thing.
Desire is the psychological wish to have sex
Arousal is the physiological response of your body to prepare for sex
Desire and arousal work independently, meaning you can have either without the other. So Addyi increases desire, while its male counterpart Viagra bypasses desire altogether to promote arousal (though presumably the desire is there to prompt popping the pill in the first place). At the end of the day, having both desire and arousal will lead to the most satisfying sex. So does Addyi impact arousal and most importantly satisfying sexual experiences?
Before answering this question, let me tell you what we know about how Addyi works. Unlike Viagra, Addyi does not increase blood flow to help pump up the genitalia (inciting arousal), but instead increases libido by changing a woman’s brain chemistry. To do so, Addyi interacts with 2 receptors in the brain: one that it blocks and one that it tickles. The overall effect is simply changing the balance of these signals, but how this equates to stimulating sexual desire is not yet known.
In 3 randomized controlled trials comparing Addyi to a placebo pill, Addyi increased the number of satisfying sexual encounters by almost 2 per month for premenopausal women and about 1 per month for postmenopausal women. That might not seem so great, but for someone who has low libido, bonus sex (even once a month) may be just enough to rescue a relationship.
Like all drugs, Addyi is associated with a variety of side effects. The most common include dizziness, somnolence, and fatigue (ironically 3 circumstances more likely to reduce sexual desire). Although rare, the most dangerous side effect is an increased risk of fainting caused by a drop in blood pressure due to the interaction between Addyi and alcohol. Because of this side effect, Sprout only received approval from the FDA with a bunch of qualifiers attached (called Risk Evaluation and Mitigation Strategy [REMS]), which may make it difficult to actually get a prescription.
So back to my original question, why all the negative media about Addyi? Well, some of it surely has to do with the dangerous side effects of mixing alcohol and Addyi. Some have argued that these risks far outweigh the (marginal, modest, minimal) reward of increasing sexual desire:
“[Addyi] is typically only marginally effective in promoting sexual satisfaction among a group of women who meet the profile for sexual dysfunction” -John Carroll, FierceBiotech
“women should expect only a very modest benefit from the drug” -Ed Silverman, Boston Globe
“[Addyi is] a drug that was at best minimally effective” -Andrew Pollack, New York Times
However, I’d argue that we can’t really judge whether this small increase in satisfying sexual experiences are “minimally beneficial” to a woman’s life (or her partner’s for that matter). If you’re one of the 12% with HSDD and you don’t drink alcohol, Addyi may just be the blessing you and your partner have been waiting for. As Addyi needs to be taken daily though, it is absolutely crucial to abstain from alcohol. If you need to choose between SEX and ALCOHOL (what a horrifying decision!), you probably shouldn’t consider Addyi. It’s not clear how many women with HSDD do not drink, but it’s obvious that this certainly limits the market for Addyi. However, why some would squash the hopes of a smaller pool of women with HSDD that don’t drink is beyond me. Do these people also think that drugs to treat rare diseases are unnecessary?
Other controversy exists, as some argue that HSDD was “invented” by the drug industry. This might shock a lot of you, but this isn’t new. Obviously, in order to market a new drug, it has to 1) be safe and 2) treat a disease. Sometimes diseases are so complicated that we don’t have a true grasp of the progression of disease, how to diagnose it, and sometimes even what to call it. Wrapped up in the billions of dollars spent by pharmaceutical companies to test their drugs, may be research on the disease itself. No doubt this may be a conflict of interest, but as Dr. Lindsey Baden, Deputy Editor of the New England Journal of Medicine, recently told me, “All research is biased. Some, like financial bias, is just easier to identify”.