The topic of female sexual dysfunction has been brought front and center due to a recently published NY Times article discussing the ongoing clinical trials of Lybrido and Lybridos, two drugs currently being studied in women reporting chronically low libido.
The studies are being conducted by the clinical research center Emotional Brain in both the Netherlands and the U.S. Lybrido is being developed for women with hypoactive sexual desire disorder (HSDD) with a relatively insensitive system for sexual cues, while Lybridos is being investigated in women with HSDD and maladaptive sexual inhibitory mechanisms. Both drugs help to increase libido about 3 to 6 hours after intake.
Lybrido combines testosterone with sildenafil, a PDE5 inhibitor that produces smooth muscle relaxation and allows for blood flow into the organs of arousal. Sildenafil is the active ingredient of Pfizer‘s Viagra, a product approved for treating erectile dysfunction. Lybridos combines testosterone with buspirone, an anti-anxiety medication. Buspirone acts on serotonin (5-HT1A) receptors, suppressing the release of serotonin into the bloodstream.
An increase in serotonin levels, known to cause a decrease in sex drive, results in a declined release of the neurotransmitter associated with feelings of desire, dopamine, from the medial preoptic and ventral tegmental areas, says Jim Pfaus, PhD, professor of psychology and neuroscience at Concordia University in Montreal. Though the mechanism of action is not fully elucidated, the testosterone component of these drugs promotes the production and release of dopamine.
While some may see the development of a low libido therapy as a milestone for women, critics are worried that the approval of a pill to treat female sexual dysfunction may bring on a societal change not seen since the introduction of the birth control pill.
As stated by Daniel Bergner from the NY Times, “More than one advisor to the industry told me that companies worried about the prospect that their study results would be too strong, that the FDA. would reject an application out of concern that a chemical would lead to female excesses, crazed binges of infidelity, societal splintering.”
There is a misconception in the discussions surrounding drugs like Lybrido and Lybridos, which are often referred to as ‘female Viagra.’ “Viagra meddles with the arteries; it causes physical shifts that allow the penis to rise. A female-desire drug would be something else. It would adjust the primal and executive regions of the brain. It would reach into the psyche,” says Bergner.