Dapoxetine, sold under the brand name Priligy among others, is a selective serotonin reuptake inhibitor (SSRI) used for the treatment of premature ejaculation (PE) in men ages 18 to 64 years old.

In May 2012, US-based Furiex Pharmaceuticals reached an agreement with ALZA Corp and Janssen Pharmaceuticals to market dapoxetine in the United States, Japan, and Canada, while selling the rights to market the drug in Europe, most of Asia, Africa, Latin America, and the Middle East to Menarini.

[9] Randomized, double-blind, placebo-controlled trials have confirmed the efficacy of dapoxetine for the treatment of PE.

Waldinger's meta-analysis shows that the use of these conventional antidepressants increases IELT two- to nine-fold above baseline, compared to three- to eight-fold when dapoxetine is used.

These pharmacokinetics are more favorable in that they might minimize drug accumulation in the body, habituation, and side effects.

[14][15] Dapoxetine should not be used in men with moderate to severe hepatic impairment and in those receiving CYP3A4 inhibitors such as ketoconazole, ritonavir, and telithromycin.

[6] The most common effects when taking dapoxetine are nausea, dizziness, dry mouth, headache, diarrhea, and insomnia.

Taken as needed, dapoxetine has very mild adverse effects of decreased libido (<1%) and erectile dysfunction (<4%).

Treatment for these patients should consider the drug–drug interaction between dapoxetine and PDE5 inhibitors such as tadalafil (Cialis) or sildenafil (Viagra).

[24] Clement's study performed on anaesthetized male rats showed that acute administration of dapoxetine inhibits ejaculatory expulsion reflex at supraspinal level by modulating activity of lateral paragigantocellular nucleus (LPGi) neurons.

[27] Dapoxetine is metabolized extensively in the liver and kidney by multiple enzymes such as CYP2D6, CYP3A4, and flavin monooxygenase 1.

The major product at the end of the metabolic pathway is circulating dapoxetine N-oxide, which is a weak SSRI and contributes no clinical effect.

Phase III studies in men with PE showed a safety and well tolerated profile of dapoxetine with dosing of 30 and 60 mg. No cardiovascular adverse had been found.

[33][34] The lack of chronic serotonergic stimulation with on-demand dapoxetine minimizes the potentiation action of serotonin at synaptic cleft, thus decreasing the risk of discontinuation symptoms.

It never worked out well as a medication for the treatment of depression, though, and was shelved for a while before subsequently developed to treat PE.

In December 2003, Eli Lilly sold the patent for dapoxetine to Pharmaceutical Product Development (PPD) for US$65 million.

Eli Lilly may also receive royalties payment from PPD if the sale exceeds a certain amount.