Addyi (Flibanserin): 25 Things You Need to Know

Getting the Facts Right

Flibanserin—the long-awaited “pink pill” for women with Hypoactive Sexual Desire Disorder (HSDD)—was finally approved by the FDA last August, after years of debate. But so far the only women who’ve actually been able to try it have been subjects in clinical research trials. No woman has yet to be able to get a prescription for it from her doctor.
That’s going to change at the end of this week. Starting October 17, a woman will actually be able to take a prescription for flibanserin (which is marketed by Sprout Pharmaceuticals under the trade name Addyi) to her pharmacy.
What’s the best way for a woman to know whether flibanserin/Addyi would be safe and effective for her? Good question.  There’s a lot of misleading information out there. (More on that in future blog posts).
Your best move is usually to ask your doctor. But there aren’t many doctors yet who know much about this new medication.
So I’ve prepared this list to get you started:  25 things a woman should know before considering taking Addyi.


1. What is Addyi/flibanserin, and why is it such a big deal?

Addyi is the trade name for flibanserin, a new non-hormonal prescription medication for hypoactive sexual desire disorder (HSDD) in women.  Addyi/flibanserin is the first medicine ever specifically approved to treat loss of sexual desire in either men or women.

It’s also potentially important for sexual science — since FDA approval of flibanserin is likely to lead to much more research on the neurochemistry of desire.


2. Does Addyi really work?

Flibanserin doesn’t work for everybody. But 46-60% of women with HSDD, or a little more than half, reported clear benefit from flibanserin in randomized placebo-control clinical trials.


3. How does Addyi work?

No one knows for sure what the mechanism is.  But serotonin in the brain inhibits sexual function, and flibanserin reduces brain serotonin activity — which may account for its effectiveness in restoring desire. Flibanserin also has indirect effects on dopamine and norepinephrine, which may be relevant as well.


4.  Is Addyi a hormone?

No. Flibanserin doesn’t contain estrogen or testosterone or any other hormone. Addyi is a psychotropic medication. It acts specifically on serotonergic neurons in the brain, and has indirect effects on dopamine and norepinephrine.

Serotonin in the brain is generally thought to put the brakes on sex. Flibanserin may help ease up on the serotonin braking system, so libido can get going again.


5.  Is Addyi safe?

The clinical trials data presented to the FDA on flibanserin included results from over 11,000 patients — one of the largest data-sets ever presented in the FDA’s history.  The safety of this medication has been evaluated more stringently than that of most new drugs approved by the FDA.

That being said, there is still much that is unknown about flibanserin — as with any other recently-approved medication. Rare but serious side effects are sometimes only discovered after a drug has been in general use for months or years. So expect your prescriber to monitor your treatment carefully.


6.  What about side effects?

The two side effects that the FDA looked at most carefully before approving flibanserin were (1) sedation, and (2) dizziness or fainting due to a drop in blood pressure.

Sedation was common in the clinical trials, and was usually mild. The FDA specifically asked for information on women’s ability to drive the next day after taking it. No evidence of driving impairment was detected. In fact, driving performance seemed to be better in people who’d taken flibanserin than in people who hadn’t taken it.

Dizziness, or fainting due to a drop in blood pressure, were less common. But serious drops in blood pressure were noted in many subjects in so-called “challenge studies” — where volunteers took flibanserin together with medications known to increase blood levels of the drug, or took the drug and then consumed the equivalent of 2-4 shots of liquor.

Of note, most of the subjects in the alcohol challenge studies were men. Apparently it was not easy to find female volunteers willing to take this medication together with 2-4 shots of liquor in the morning.

The results of these challenge studies led the FDA to mandate a “black-box warning” requiring patients to avoid using alcohol while taking flibanserin — and to avoid this medication while taking moderate to strong Cytochrome p450 inhibitors such as fluconazole (Diflucan and others) which can increase flibanserin blood levels.


7.  What women are most likely to benefit from Addyi?

We don’t know. The clinical studies on flibanserin were done with women who had what we call “generalized, acquired HSDD.” All of these women were in long-term, stable monogamous relationships.  They’d had sexual desire in the past, and were distressed at having lost it and wanted it back. The average length of time women in the study had suffered with HSDD was five years. These women reported feeling no desire for their partner, or for anyone else.

For women who fit this profile, clinical trials data would predict a 46-60% chance of a meaningful response to flibanserin.  For other patterns of symptoms (such as lifelong absence of desire, or desire for other people but not their primary partner), we don’t know how effective Addyi might be.


8.  Is “Hypoactive Sexual Desire Disorder” (HSDD)  a real condition?

There’s no laboratory test to confirm a diagnosis of HSDD. But that’s typical for conditions that involve the brain and mind.

Diagnosis of such mental disorders usually relies on pattern recognition. Asking, “Do this patient’s symptoms fit any established patterns that research has shown respond to specific treatments?”

In diagnosing HSDD, a clinician needs to ask, “Did this woman once have sexual desire? Does she seem to have lost it permanently? Is she distressed about it? And have we ruled out all of the common things that can cause loss of desire — such as prescription medications or general unhappiness in the relationship?” If she meets this pattern, then it’s likely she has HSDD.


9.   Why is HSDD such a big deal?

It’s not just the loss of desire. It’s the impact of vanished libido on a woman’s sense of self, and on her relationships.

Many women with HSDD fake excitement during sex, going through the motions while waiting for it to be over. Some women avoid being affectionate with their partners, for fear their partner will want sex. These kinds of behaviors can further diminish desire, and before long can cause  serious problems in a relationship.

In surveys, the majority of women with HSDD report that their loss of desire had negatively affected their self-confidence, their body image, and their feeling of connection with their partners. It’s not uncommon for HSDD to destroy a marriage.


10. How long does Addyi take to work?

The clinical trials data suggest that flibanserin can take up to four weeks to see results, and up to eight or twelve weeks to see maximum results.


11.  How long should I take Addyi before deciding it’s not effective?

Based on the data in the clinical trials, if you haven’t seen any effect on sexual desire after taking Addyi for 12 weeks, then you’re probably not a responder.


12. What if I feel desire for someone else, but not for my committed  partner? Will Addyi help increase my desire for my partner?

If you’re able to feel desire for someone outside your primary relationship, then you probably don’t have HSDD as strictly defined in the flibanserin clinical trials.

Does that mean that Addyi won’t help you? We don’t know. The studies were all done on women with generalized loss of sexual desire.


13.  Will Addyi make me hyper-sexual?

No, the data seem to indicate that flibanserin doesn’t cause hypersexuality.  It didn’t make the women in the clinical trials want sex all the time.

Addyi is not an aphrodisiac. It’s not like eating oysters. Which, by the way, probably doesn’t do much anyhow — unless you’re already in the mood.


14.  Will Addyi interfere with my ability to say “no” to sex?

Absolutely not. Since flibanserin tends to restore a woman’s natural desire, women on Addyi will probably find they have the same degree of good judgment as they had before they lost their libido.

Women with HSDD typically report that they can’t shut off the “thinking and planning” parts of their minds enough to concentrate on sex. What flibanserin seems to do is to help a woman with HSDD to say “no” to all the other things she might be worrying about — so she can think about sex again.


15.  Will Addyi eliminate the need for sex therapy?

I’m pretty sure Addyi won’t put sex therapists out of business. Sex is multifactorial. There are biological and psychosocial inputs. So restoring a woman’s biological desire is only part of the picture.

I think one of the most exciting things is going to be collaboration between sex therapy and sexual medicine. That’s what’s going to lead to the most number of people getting the most effective help.


16.  What if I don’t feel any effect from Addyi?

If a woman takes Addyi for 8 to 12 weeks as directed, and doesn’t notice any difference in her libido, then it’s likely she’s a non-responder.  Almost half of women in clinical trials didn’t report much response to flibanserin.

For women who don’t respond to Addyi, there are off-label prescription treatments such as bupropion (Wellbutrin and others) and very low dose testosterone gel. But since they’re off-label, they require a careful discussion with your doctor.  You may specifically want to consult with a sexual medicine specialist.

As a sex therapist who’s also an MD, I’ve seen many female patients report restored libido on bupropion. But the majority were at least somewhat depressed, so it’s difficult to know exactly that the therapeutic mechanism was.


17. If Addyi works for me, how long will I need to take it before I can stop it?

The short answer is that a woman can stop Addyi anytime she wants. But what women really want to know of course is whether their libido, once it’s been restored, will stay restored after they go off the medicine.

That’s an unanswered question. The technical term for it in sex therapy is “bridging” to unassisted sex. No one has yet studied how many women are going to be able eventually to “bridge” to not needing flibanserin, versus how many are going to keep needing it.

The maximum time flibanserin has been studied in premenopausal women is 18 months, and it appears to keep working over that timespan without losing its effectiveness.  But more research is going to be necessary before we can say how enduring the effects might be after stopping the drug.


18.  Will Addyi make me gain weight?

This question was looked at specifically in the clinical trials. Overall, patients did not gain weight on flibanserin.  In fact, there was some tendency to weight loss.


addyi flibanserin 25 facts


19.  Are there any natural alternatives to Addyi that are worth considering?

It’s a challenge to prove that any one treatment for desire is better than placebo.  Flibanserin beat placebo on all self-report measures of desire, satisfaction, and distress in randomized controlled trials. That’s an impressive result.

Most herbs and supplements that claim to increase desire contain combinations of several agents.  It’s very difficult scientifically to prove that even one agent makes a difference for desire. When you combine several different agents, you’re basically admitting it’s more hope than science.


20.  Are there are any women who should NOT take Addyi?

There are some important medical contraindications. For instance, a woman taking Addyi should avoid using alcohol, and should avoid certain medications such as fluconazole (Diflucan and others) that can increase blood levels of flibanserin.

In my opinion, there are psychological contraindications as well. For instance, the situation where a woman’s motivation to take medication comes from her partner, rather than from the woman herself.

Addyi is serious medicine. Don’t try it just because your partner wants you to. A woman should only take Addyi if she herself wants to feel sexual again. It should be entirely her own choice.


21.  Will Addyi help women who’ve lost desire after taking serotonin reuptake inhibitors such as Prozac?

This will most likely be an active area of research. Loss of libido on SRI antidepressants is a big problem in psychiatry. Especially because there are many women with panic disorder, OCD, or serious depression for whom nothing else works.

A lot of people are going to be curious about whether flibanserin can help women on SRI’s, and we’ll look forward to seeing the results when this research is done.


22.  Will Addyi work for older women and post-menopausal women?

Older women suffer from HSDD as well as younger ones.  Flibanserin has been studied in post-menopausal women with HSDD, and it appears to be effective.  But for now its use in post-menopausal women is off-label.


23.  Can I take Addyi if I’m on birth control pills?

Use of Addyi together with birth control pills can be associated with higher levels of flibanserin, and therefore greater risk of side effects.

Note: In some cases, birth control pills can be a factor in a woman’s loss of libido. My own approach is to recommend that a woman first switch to some other kind of contraception. In some cases this can improve desire, though there can be a delay of many months to over a year before desire returns.


24. What’s more effective — Addyi or sex therapy?

That depends on a lot of factors, including what caused a woman’s loss of desire. Sometimes the causes seem to be mostly situational (such as chronic unexpressed anger in a relationship). Flibanserin is probably not going to be helpful in a situation like that.

But some women in perfectly happy relationships experience a serious loss of desire following a life event such as the birth of a child, and desire never returns. In that kind of situation, a biological treatment such as flibanserin may make more sense.

Most women will want to try psychological counseling first before medication. That’s reasonable. But very often counseling doesn’t bring back desire. If you ask sex therapists, most of them will tell you that loss of desire can be the most difficult problem to treat.

Most sex therapists appreciate anything that adds to their toolbox of things that can help restore desire. Ultimately the best treatments for HSDD and related conditions may involve collaboration between sexual medicine and mental health providers. Very often the best treatment may not be “either/or,” but both.


25.  How can I know whether or not I’m a good candidate for Addyi?

There’s a pocketcard online that can give you a preliminary idea of whether you fit the criteria for HSDD, which at this time is the only condition for which Addyi is indicated:

Then you’ll need to see a doctor who’s knowledgeable about Addyi — someone who can take the time to review your situation thoroughly to decide whether a medication makes sense.


None of us will know for sure how useful this new medication is, until we’ve had patients try it.  But it’s a fresh approach to  loss of sexual desire, which can be a particularly difficult problem for couples.

There will no doubt be much more clinical research on flibanserin in the years ahead — and I look forward to discussing the results with you when they become available.

Stay tuned . . .

stephen snyder md author photo Stephen Snyder, MD

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