The decades-long search for a female equivalent to the libido-boosting drug Viagra for men will not be filled any time soon. The latest drug candidate, Sprout Pharmaceuticals’ filbanserin, was rejected by the Food and Drug Administration (FDA). The agency questioned whether the drug’s benefits – which it said were “modest” at best – outweighed the potential side effects, which include fatigue, dizziness and nausea.
Developing drugs to boost female sexual desire is a complicated science because the root cause can be multifaceted – such as psychological – and thus harder to understand and measure. “And, quite honestly, we don’t know enough about what creates sexual motivation (in women) to manipulate it,” says Emory University researcher Kim Wallen. Comparatively, erectile dysfunction in men is easy to measure.
Over the years, drug makers have fruitlessly attempted to tackle the issue. At first, Pfizer tested Viagra on women hoping that the drug’s ability to increase blood flow to genitals would have the same effect on women as it does on men. It didn’t. Other drug companies have tested the male hormone testosterone in women and, while that proved effective, the potential long-term side effects were too worrisome to win FDA approval.
Sprout’s filbanserin took another approach to boosting women’s sexual desire – by upping dopamine in the brain, a transmitter that is associated with appetite, while simultaneously lowering serotonin, another transmitter associated with satisfaction. Sprout says clinical trials showed the drug boosted sexual desire, reduced stress and increased “sexually satisfying events,” among women with hypoactive sexual desire disorder, a condition in which lack of sexual desire causes stress.
Sprout said it was appealing the decision, an uphill battle considering the FDA only approved three of the 17 appeals it received last year. Sprout contends that its data shows statistically significant improvement in women and that alone should warrant approval, considering there are no approved libido-boosting drugs for women.
On the other hand, there are 24 approved treatments that boost sexual desire in men including testosterone supplements.
Source: ABC News