The (maybe) soon-to-be-approved “female Viagra” releases the brain’s sexual brakes. The drug flibanserin, intended to treat low sexual desire in women, isn’t exactly the pink version of the little blue pill. Rather than pushing blood flow to the genitals, flibanserin targets key neurotransmitters that are involved in sexual response: dopamine, norepinephrine, and serotonin. The drug increases the amount of dopamine and norepinephrine, which are like the brain’s accelerators when it comes to sexual response; at the same time, it turns down the level of serotonin, which is responsible for inhibition. Since 2010, the FDA has twice shot down flibanserin. Each time, the drug manufacturers couldn’t prove to a review panel that the medication’s benefits were greater than the risks it posed. Flibanserin gets a third chance at approval this summer — this month, an advisory panel was convinced that flibanserin is safe to use for women taking antidepressants and that the drug does...