Flibanserin requires a whole new understanding of “Viagra” for those who are familiar with the male Viagra sildenafil. While sildenafil acts specifically on the penis, and only acts when a man is aroused — it does nothing to arouse the man itself — flibanserin is completely different.

The “pink pill” does not work on the groin. Although not completely understood, it is thought to work on the brain, increasing desire rather than allowing body parts to function optimally.

Some scientists believe that some individuals who have little or no feelings of sexual desire may have an imbalance of excitatory and inhibitory neurotransmitters, and so neural activity is not controlled in ways that promote sexual arousal.

Flibanserin increases certain chemicals in the brain while blocking others. This effects an increase in mood chemicals that are considered to be associated with sexual desire.

Another difference between the two drugs is that sildenafil can be taken when needed and lasts 2-4 hours. Flibanserin needs to be taken every day to work.

A third difference is efficacy: men with erectile dysfunction achieve erections 67 – 89 percent of the time with Viagra compared to 27 – 35 percent when taking placebos, and the chance of a man who has taken sildenafil achieving successful sexual intercourse roughly doubles from 35 percent to 69 percent.

The efficacy of flibanserin is only known from tests in which women were found to have an average of one extra sexually satisfying experience every 28 to 56 days (yes, one extra every month or two).

Both drugs have undesirable side effects.

The side-effects of sildenifil can include dizziness, headache, flushing and upset stomach. Also, some men experience increased sensitivity to light, blurred vision, and color blindness to blue and green.

Flibanserin also has several undesirable side-effects: marked sedation, sleepiness and fatigue, which side-effects are made worse if a woman drinks alcohol or takes medication that alters the metabolism of the drug.

By Cheryl Bretton