Erectile Dysfunction drugs such as Viagra, Cialis, and Levitra have made huge strides in treating male sexual dysfunction — but have women been left behind? At this writing (September 2009), no treatment has been approved by the FDA for Female Sexual Dysfunctions (FSD), which are estimated by the Journal of the American Medical Association to affect 43% of American women (about 40 million) at some point in their lives.

It’s not for lack of trying. Pharmaceutical makers would love to tap into a market that’s the other 50% of the population. They are assertively researching the problem. So why has a result not come forward?

One issue is that, with men, “sexual dysfunction,” no matter whether the cause is mental or physical, is likely to respond as a pretty straightforward plumbing problem: Viagra and its counterparts, the Phosphodiesterase Type 5 Inhibitors, are vasodilators, meaning that they open up blood flow to the area, allowing an erection to be achieved and retained more easily. (More information on the effects of these vasodilators on women is below.)

But women’s sexuality is more complex and less understood, often caused by a range of physical, emotional, and psychological conditions. Simple manipulation of bloodflow only goes so far. Another element is that women have unique hormone issues, which often cause low libido, as they age. Finally, some researchers are experimenting with methods that place sexuality in the mind.

The good news is that research IS progressing. Here’s an update on where the various methods are:

THE BIG THREE (Viagra, Cialis, Levitra)

Researchers are looking into using male ED drugs on women suffering from FSD. In April of this year, a study by the American Physiological Society was described that compared the effects of three drugs used for erectile dysfunction (Viagra (sildenafil), Levitra (vardenafil), and Cialis (tadalafil)) on female rats. The researchers discovered that these drugs significantly increased blood flow to female sexual organs, and show promise for treating similar conditions in human women. Another study has shown that Viagra can help with orgasms in women who are taking SSRIs and suffering sexual dysfunction as a side effect.

There is promise here, but it is all forward-looking. The FDA has not approved these medications for use by women. We will be closely following the progress of this research.

HORMONAL TREATMENTS

The hormone testosterone drives sexual desire, and as women age, they typically lose some of both. There are some doctors that prescribe testosterone off-label to women to help with low desire, but this process is not approved by the FDA. There have been flops along the way to a hormonal treatment. Intrinsa, a testosterone patch for women, was turned down by the FDA in 2004 due to worries about long-term safety, and PT-141 was a nasal spray that was being tested to raise desire in both men and women when it was quashed by the FDA for having possible blood-pressure-related side effects.

In upcoming news, though, BioSante Pharmaceuticals of Illinois is in late-stage studies of a testosterone gel intended to remedy libido loss after menopause. The product, called LibiGel, is smeared on the upper arm and promotes a long, slow build-up of testosterone in women. We’ll be eagerly watching to see if LibiGel is approved by the FDA.

NEUROTRANSMITTER ADJUSTMENTS

A nonhormonal treatment for FSD is in late-stage testing. Boehringer Ingelheim’s Flibanserin, a pill to be taken daily, acts on serotonin receptors in the brain. Early reports suggest that the medication was not useful for treating depression (its intended use), but had the curious side effect of increasing desire in females. The company is now researching the drug’s effects directly in younger, premenopausal women who are suffering from low desire.

The reality is that there is no approved pharmaceutical treatment on the market for a condition that troubles millions of women. The good news is that there are a few promising treatments on the horizon, and we encourage women to follow issues like this in the news so that they will know when relief becomes available. Some of the companies mentioned in this article are conducting clinical trials of these medications, so if you are deeply interested and want to participate, that is a possibility, too. We should see some major changes in the field in the next few years.