Dapoxetine is a short-acting selective serotonin reuptake inhibitor (SSRI) marketed for the treatment of premature ejaculation in men. Dapoxetine is currently in Phase III (human trials) of the U.S. Food and Drug Administration (FDA) approval process. Dapoxetine is the only approved clinical treatment chemical for premature ejaculation, ever, in men, in the world. SSRIs have long been known to cause prolonged ejaculation in men and orgasmic difficulty in women; however, the longer duration of most SSRIs means they would not be suitable for treatment of a single issue like PE when the other effects would likely outlast the benefits of treating PE. Studies have suggested that dapoxetine has strong potential in the treatment of premature ejaculation. In a review of data gathered from the phase III trial, authors conclude from data that dapoxetine is well-tolerated. Secondary effects of premature ejaculation such as personal distress, interpersonal difficulty in relationships, and low satisfaction with sexual intercourse were also improved.
In 2004, dapoxetine was submitted to the FDA by the ALZA Corporation (owned by parent company Johnson & Johnson) for the treatment of premature ejaculation. The FDA issued a "not approvable" letter for dapoxetine, meaning they required additional clinical examination submitted in the form of a peer-reviewed study. Two more trials were completed in 2006 and the drug is still under FDA reviewing process as of 2010.
Dapoxetine is currently at the center of a significant amount of controversy; see, for example, a comment by Waldinger and Schweitzer in J Sex Med:
Time until ejaculation during sexual intercourse is highly variable. Some men and their partners find sex unsatisfactory because they feel ejaculation occurs too quickly. Psychobehavioural therapy is the first option. Dapoxetine, a short-acting serotonin reuptake inhibitor, is the first drug to be authorised for use in premature ejaculation in some EU member states. Four double-blind randomised placebo-controlled trials in a total of 4414 men are available. At best, only one in three men and one in five women perceived at least a moderate improvement in sexual satisfaction through a specific effect of dapoxetine. A substantial placebo effect was observed in one-third of participants of both sexes. Dapoxetine exposes men to the numerous adverse effects of all serotonin reuptake inhibitors, some of which can be severe, such as self-harm, aggressive behaviour, and serotonin syndrome. Postural hypotension and syncope can also occur. Dapoxetine is strongly metabolised by the cytochrome P450 isoenzymes CYP 3A4 and CYP 2D6, and thus carries a risk of numerous pharmacokinetic interactions. In practice, there is no justification for exposing men to potentially serious adverse effects for only a moderate symptomatic improvement in a poorly defined disorder. Behavioural approaches should remain the cornerstone of therapy.
The same researchers use the controversy over dapoxetine to question the validity of the peer-review process as it pertains to studies funded by pharmaceutical companies:
The manufacturer of dapoxetine funded randomized clinical trials to study its effect in premature ejaculation (PE). Financial support by pharmaceutical companies, however, may jeopardize the neutrality of clinical research. ...Manufacturer-funded drug treatment research is advantageously treated by some authors as compared with nonfunded trials with daily conventional SSRIs. PE drug treatment research is a young and dynamic field, and its development deserves transparency to its development.
Kendirci M, Salem E, Hellstrom WJ . Dapoxetine, a novel selective serotonin transport inhibitor for the treatment of premature ejaculation. Ther Clin Risk Manag 3 (2): 277–89. 2007.
Janssen-Cilag EMEA announces receipt of first regulatory approvals for Priligy for PE in Finland and Sweden. (2/11/2009)
Safarinejad MR .Safety and Efficacy of Dapoxetine in the Treatment of Premature Ejaculation: A Double-Blind, Placebo-Controlled, Fixed-Dose, Randomized Study. Neuropsychopharmacology 33: 1259. (2007).
News – Johnson & Johnson Prescrire Int. 2010 Feb;19(105):12-4.
Waldinger MD, Schweitzer DH. Dapoxetine. Premature ejaculation: not worth the risk. J Sex Med. 2008 Apr;5(4):966-97.
Waldinger MD, Schweitzer DH. Premature ejaculation and pharmaceutical company-based medicine: the dapoxetine case. J Sex Med. 2008 Apr;5(4):966-97.
*The latter article is intended for educational / informational purposes only. THIS PRODUCT IS INTENDED AS A RESEARCH CHEMICAL ONLY. This designation allows the use of research chemicals strictly for in vitro testing and laboratory experimentation only. Bodily introduction of any kind into humans or animals is strictly forbidden by law.