The "most popular" ones you're referring to are SSRIs (selective serotonin reuptake inhibitors), which work by binding to 5-HT2 receptors in your brain and prev

The "most popular" ones you're referring to are SSRIs (selective serotonin reuptake inhibitors), which work by binding to 5-HT2 receptors in your brain and preventing (unsurprisingly) the reuptake of serotonin, leading to more serotonin present in the synapses. Serotonin is generally associated with positive mood, but it also delays orgasm, so patients taking SSRIs frequently report anorgasmia, or inability to reach orgasm. I suspect the "second most popular" you refer to would be bupropion, tradename Welbutrin, which is mildly stimulating, and thus pro-sexual.