The first tailor-made drug for premature ejaculation has been found to be safe and effective, a report says.
Treatment for premature ejaculation is much needed
The drug dapoxetine lengthened the duration of intercourse by three to four times in an American study of 2,600 men, the Lancet reported.
University of Minnesota researchers found taking the drug increases the average duration of sex from less than a minute to three minutes 19 seconds.
Premature ejaculation affects up to a third of men.
There is currently no medication for the condition on the market.
Treatments involve counselling and the use of anti-depressants from dapoxetine's family of drugs - selective serotonin reuptake inhibitors (SSRIs) - although these are not specifically licensed for premature ejaculation.
Indeed, some experts have raised concerns about these drugs being used as they carry a risk of side effects including psychiatric problems, skin reactions and changes in bodyweight.
While dapoxetine is an SSRI, it is not as strong as ones used to treat depression, and has been specifically tailored for premature ejaculation. It can be used on-demand rather than needing to be taken over the long-term.
The team, led by Dr Jon Pryor, combined results from two trials.
More than 2,600 men with moderate to severe ejaculation problems were included and either received a placebo, 30mg of dapoxetine or 60mg of dapoxetine.
On average, at the start of the study, the men ejaculated less than a minute after penetration.
After 12 weeks, that time extended to an average of one minute 45 seconds for those on the placebo, two minutes 47 seconds for those on 30mg dapoxetine, and 3 minutes 19 seconds for those on 60mg dapoxetine.
Dr Pryor said: "Dapoxetine also improved patients' perceptions of control over ejaculation, satisfaction with sexual intercourse, and overall impression of change in condition.
"Partners benefited through improved satisfaction with sexual intercourse."
The drug, made by ALZA Corporation, whose parent company is Johnson & Johnson, is not currently licensed for use in the UK.
But in an accompanying editorial in the Lancet, Italian urologist Francesco Montorsi said the drug had been shown to be safe and tolerable.
He added: "The hope is that on-demand dapoxetine will become an important drug to offer patients with premature ejaculation."
Peter Baker, from the Men's Health Forum, said: "There is really very little treatment for premature ejaculation so any drug which may help would be welcome.
"However, one of the major obstacles to treatment is convincing men to seek help. It is a very common problem, but many feel to embarrassed to talk to doctors and other health professionals."