Flibanserin is a full agonist of the serotonin 5-HT1A receptor and an antagonist of 5-HT2A (Kis = 1 and 49 nM, respectively). It also binds to dopamine D4 receptors with Ki values ranging from 4-24 nM, but demonstrates no affinity for the other 5-HT subtypes or other neurotransmitter receptors. In vitro, flibanserin has been shown to reduce forskolin-stimulated cAMP formation in cells and rat tissues and to antagonize the accumulation of phosphatidyl inositol turnover induced by 5-HT in the mouse cortex. At 10 mg/kg, flibanserin can reduce serotonin in the prefrontal cortex and dorsal raphe of conscious rats while increasing extracellular noradrenaline and dopamine. Multifunctional serotonergic ligands like flibanserin that can enhance downstream release of dopamine and norepinephrine while concomitantly reducing serotonin release in the brain circuits that mediate symptoms of reduced sexual interest and desire are being studied clinically for therapeutic potential to improve sexual functioning.
