Another Run for Pink Viagra?

Ever since Flibanserin was shelved after FDA rejection, the search for the next drug to treat lack of libido in women has been mighty low-key. To be sure, there were legitimate concerns about Flibanserin’s effectiveness, but as I’ve said before, we need more treatment options for women who suffer from hypoactive sexual desire disorder (HSDD).

Now, three years later, initial trials on another pink Viagra drug, which are actually two drugs (Lybrido and Lybridos), are just winding down. The results look “very, very promising,” according to Adriaan Tuiten, the drugs’ developer. If all goes well in the next phase of clinical trials, a pink Viagra could be on pharmacy shelves by 2016.

And that would be something to celebrate.

As I mentioned in my last post, HSDD is common; it’s complex; and it has confounded therapists and researchers for decades. Unlike pills for erectile dysfunction, low libido in women isn’t just a matter of hydraulics—increasing blood flow to the genitals (although it’s partly that).

Therapists and physicians have debated long and hard over female sexual desire—what creates it; what kills it; even what it is. Sexual desire probably has as much to do with our brains and our emotions as it has to do with our plumbing. And, possibly, desire may even be connected to the way women are hard-wired for sex, commitment, and monogamy.

It appears that women like novelty maybe even more than men. And while women don’t tend to be more promiscuous than men, they do tend to fizzle out, sexually speaking, more quickly and persistently within long-term relationships. They just lose interest.

“Sometime I wonder whether it [HSDD] isn’t so much about libido as it is about boredom,” says Lori Brotto, a therapist who has worked extensively on female libido, in this article in the New York Times magazine.

It’s also about loss of hormones that we experience—right about now.

This doesn’t mean that women who suffer from loss of libido don’t love their mates. It doesn’t mean that they can’t become aroused or even experience orgasm. It does mean that the sexual attraction, the heat and fizz, the interest in being sexual has waned or disappeared.

You know, the old “not tonight, dear. I have a headache” routine.

Every night.

Make no mistake, for many women this is a real heartbreak. “How much easier it would be if we could solve the problem by getting a prescription, stopping off at the drugstore and swallowing a pill,” writes Daniel Bergner, author of the forthcoming book What Do Women Want?

This next frontier may be attained if Tuiten’s sister-drugs for HSDD —Lybrido and Lybridos—continue to be as effective as early trials suggest.

The two drugs affect three chemicals thought to be involved with sexual desire and arousal in women: testosterone, dopamine, and serotonin. But each drug takes a slightly different approach.

Both have a testosterone coating that melts in the mouth and enters the bloodstream quickly. Lybrido then works something like Viagra, increasing bloodflow to the genitals, which may heighten a woman’s awareness of her own arousal, releasing a resultant cascade of dopamine, the neurochemical of passion, in the brain.

Lybridos, on the other hand, use an anti-anxiety drug, called Buspirone, instead of the Viagra look-alike. After the testosterone rush, Buspirone temporarily suppresses the production of serotonin, a “higher order” neurochemical that creates feelings of well-being and self-control. Squash the voice of reason (serotonin) and perhaps passion (dopamine) will gain the upper hand. Or so the thinking goes.

Preliminary results from these trials were recently published in The Journal of Sexual Medicine. The next round will involve a much larger study.

“Perhaps the fantasy that so many of us harbored, consciously or not, in the early days of our relationships, that we have found a soul mate who will offer us both security and passion, till death do us part, will soon be available with the aid of a pill,” writes Bergner in the Times article.