New drug to treat hypoactive sexual desire in women, Vyleesi, is not very effective and has several drawbacks. It is NOT Viagra for women.
The FDA has approved a new drug, Vyleesi (bremelanotide) that has been hyped as “female Viagra”. It is no such thing. Viagra is used to treat erectile dysfunction in men who have sexual desire but are unable to perform. Vyleesi is used to treat women who don’t have sexual desire but want to. That is a real problem for some women, but the new drug is far from an ideal solution. It’s not very effective and is problematic in other ways.
Vyleesi is a drug marketed for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. HSDD has been estimated to occur in up to one-third of adult women, but most estimates are much lower. It is defined as:
the persistent or recurrent deficiency or absence of sexual fantasies and desire for sexual activity with marked distress or interpersonal difficulty not otherwise accounted for by a general medical or psychiatric condition…[it] may be primary or secondary, lifelong or acquired, or generalized or situational.
Distress is critical for diagnosis; some women have a low libido or even a total absence of interest in or desire for sex but are not bothered by it. Some people can best be categorized as “asexual”.
What is Vyleesi?
Bremelanotide is based on a compound that was first studied as a possible tanning product. It activates melanocortin receptors. The mechanism of how it could work to improve sexual desire is unknown. It was approved by the FDA following two clinical trials. It’s not for sale just yet, but it will probably be available in September. There is not yet any information on pricing or reimbursement. One prediction is that it may cost $50-75 per dose, with an anticipated average of four doses per month. Its long-term effects have not been studied.
It must be injected under the skin of a woman’s abdomen or thigh at least 45 minutes before she anticipates sexual activity. Use is limited to once in 24 hours and eight times per month. It is not indicated for post-menopausal women. It is contraindicated in patients with uncontrolled hypertension or known cardiovascular disease. The company website lists numerous warnings and precautions. Its safety in pregnancy has not been studied; patients are advised to use effective contraception and to stop Vyleesi if they suspect they might be pregnant. It transiently increases blood pressure and decreases heart rate. A whopping 40% of users reported nausea; 13% required anti-emetic therapy. Focal hyperpigmentation occurred in 1% of patients. Besides nausea, the most common adverse reactions (<4%) included flushing, injection site reactions, headache, and vomiting. It may slow gastric emptying and interfere with absorption of oral medications.
There have been two phase 3, randomized, double-blind, placebo-controlled trials. They have not yet been published, but the results are reported on the company website. Both studies showed a statistically significant increase in self-reported sexual desire and a significant decrease in self-reported distress. But the effect was modest. 25% of users reported an increase of sexual desire compared to 17% of those who got placebo. And there was no significant difference in the number of satisfying sexual events.
There is one other FDA-approved drug for HSDD: flybanserin, sold under the brand name Addyi. It is a tablet that must be taken regularly, once a day. It costs $426 for a month’s supply. It has not been widely adopted. It can’t be used with alcohol because it can interact to cause hypotension and syncope, and providers have to be specially certified to prescribe it. In clinical trials, the benefits were statistically significant but not impressive. After adjusting for placebo, only around 10-12% of subjects reported even minimal improvements in sexual desire, and it did not improve the ability to orgasm or the quality of sex.
Counselling, cognitive behavioral therapy, and the drugs buproprion, buspirone, and testosterone (used off-label) have also been tried for HSDD with limited success.
Is hypoactive sexual desire disorder even a legitimate diagnosis?
The diagnostic category of HSDD has been criticized on several grounds. It is poorly defined and may have more of a social function than a medical one. It may be a diverse group of conditions and may have many causes. The requirement that it causes distress may be problematic. The parameters of normality are not yet well understood. HSDD has been accused of medicalizing sexuality and pathologizing normal variations.
Conclusion: Not very effective, and problematic
I don’t see a great future for Vyleesi. The restrictions and adverse effects are cause for concern, especially the 40% incidence of nausea. Patients have to plan for injection 45 minutes before sex, and then it only increases desire without increasing the number of satisfying sexual events. How often can women plan sex 45 minutes ahead? What about spontaneity? Why would a woman want to take something that makes her horny but doesn’t lead to satisfaction?
Women who have low libido and want to raise it don’t have any really good options, especially if they are past menopause. The FDA-approved drugs are only for premenopausal women who meet certain criteria. They are not very effective, the risks are substantial, and I predict that not very many women will choose to use them.
This article was originally published in the Science-Based Medicine Blog.