Dapoxetine premature ejaculation drug molecule. Computer artwork of a molecule of the premature ejaculation drug dapoxetine. Atoms are represented as balls and are colour-coded; carbon (gold), hydrogen (translucent), oxygen (red) and nitrogen (blue). Dapoxetine belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs). SSRIs act as antidepressants, but also have the side effect of delaying ejaculation. Dapoxetine, which as of early 2007 is unlicensed in the UK, has been tailored for use as an on- demand drug for premature ejaculation, with weakened antidepressant activity.