Source: New Scientist
Date: 8 September 2006

Drug to tackle premature
ejaculation does the trick

Rowan Hooper

The first medication tailor-made to treat premature ejaculation has proven successful in trials, researchers report.

However, critics point out that existing medications are more effective at treating the condition.

Jon Pryor at the University of Minnesota, Minneapolis, US, and colleagues tested the effectiveness of a selective serotonin reuptake inhibitor (SSRI) called dapoxetine on nearly 2000 men with moderate or severe premature ejaculation (PE). Before taking the drug, these men lasted less than one minute after penetration, on average, before they ejaculated.

The men were randomly assigned to one of three groups: placebo, or treatment with 30 milligrams or 60mg of dapoxetine. The drug was taken 1 hour to 3 hours before intercourse.

After 12 weeks of treatment, the time to ejaculation was 1.8 minutes for placebo, 2.8 minutes for 30 mg of dapoxetine, and 3.3 minutes for the 60 mg dose.

“Dapoxetine also improved patient’s perceptions of control over ejaculation, satisfaction with sexual intercourse, and overall impression of change in condition,” says Pryor. “Partners benefited through improved satisfaction with sexual intercourse.”

No licence

The drug is safe and effective, the researchers say, although some participants in the study suffered side effects including nausea, diarrhoea, headaches and dizziness. The US Food and Drug Administration last year declined to grant a license for dapoxetine, which was developed specifically for the treatment of PE.

In any case, says Marcel Waldinger, a neuropsychiatrist at Leyenburg Hospital in The Hague, The Netherlands, other SSRIs are already being used to treat the condition with greater efficacy: “The best way to treat PE today is by chronic use of conventional SSRIs. These SSRIs provide an ejaculation delay of about nine-fold increase. Dapoxetine only provides an ejaculation delay of about three-fold, which is rather equal to the minimum of the ejaculation delay induced by chronic use of SSRIs,” he says.

And Waldinger also has concerns that the makers of the new medication may be trying to "pathologise" a condition that does not need treating in this way.

Normal performance

In a study he carried out in 2005, Waldinger compared the latency between penetration and ejaculation in the general population of five countries: The Netherlands, the UK, the US, Spain and Turkey. On average, men lasted for 5.4 minutes, he says, though the average latency in Turkey was only 3.7 minutes.

“Clinicians should be careful that pharmaceutical companies do not try to pathologise and medicalise men who sometimes only suffer from a rapid ejaculation, as this belongs to normal sexual performance,” Waldinger says.

In Pryor’s paper, PE is described as the most common form of male sexual dysfunction, affecting 21% to 33% of men. But in Waldinger's opinion, only men suffering from lifelong PE should receive drugs. “The prevalence of lifelong PE is most probably much lower, at 1% to 5%,” he says.

Dapoxetine is made by ALZA Corporation, whose parent company is Johnson & Johnson. The researchers in Pryor’s team are variously employees of ALZA Corporation, consultants for Johnson & Johnson or recipients of grants from ALZA. Pryor has also served on advisory boards for ALZA.

Journal reference: The Lancet (vol 368, p 929)





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