An experimental spray-on anesthetic may be the cure for many men suffering from premature ejaculation -- increasing the time to orgasm more than sixfold, according to new findings to be presented this week.
In a double-blind trial of more than 300 men with a lifetime history of prematurity, researchers found that the mean time to orgasm increased from about 0.6 minutes to 3.8 minutes in those using the spray.
The findings, to be presented Tuesday at a Chicago meeting of the American Urological Assn., were released today.
This new topical spray "has promise to become one of the most effective treatments for premature ejaculation," said Dr. Ira Sharlip, a urologist at UC San Francisco and an association spokesman. "It has a number of characteristics which will be attractive to patients."
Premature ejaculation is one of the most common sexual problems of men, striking about 1 in every 3 -- compared with 1 in 4 who have erectile dysfunction.
Researchers have generally taken two approaches to overcoming the problem: treating the brain or numbing the penis.
Scientists noted some time ago that certain antidepressants, such as Zoloft and Prozac, had a side effect of delaying ejaculation. Johnson & Johnson developed a new drug, called dapoxetine, that maximized this effect. The drug has been approved in a couple of European countries, but the U.S. Food and Drug Administration has ruled that it is not approvable, in part because of the problems associated with long-term use of such drugs.
The other approach is to use a topical anesthetic, such as EMLA cream, a combination of the anesthetics lignocaine and prilocaine in a cream base. It has not been approved for treating premature ejaculation, but many physicians prescribe it off-label.
The cream takes 45 minutes to work, however. The man must also wear a condom, or the cream will rub off on the female, preventing her from achieving satisfaction.
Dr. Michael G. Wyllie and his colleagues at Plethora Solutions Ltd. in London have developed an anesthetic spray called PSD502, or Tempe. A combination of lidocaine and prilocaine, it is absorbed only by the glans penis -- the most sensitive part of the organ -- and not by the shaft. It is quickly absorbed, so there is no danger of it rubbing off on the woman, and it acts in five minutes. "That's a distinct advantage over previous options, because it doesn't need to be used with a condom or washed off before intercourse," Sharlip said.
In their most recent trial, Wyllie and Dr. W. Wallace Dinsmore of the Royal Victoria Hospital in Belfast, Northern Ireland, recruited 300 men with documented histories of prematurity who were in monogamous relationships. Two-thirds used PSD502 and the rest a placebo.
The men were instructed to spray it on five minutes before intercourse, and then document the time from penetration to ejaculation with a stopwatch. The couples also filled out detailed questionnaires about their experiences and sexual satisfaction.
"We got a great clinical response," Wyllie said in a telephone interview. Time to orgasm increased a mean of 6.3 times in the men using the spray, compared with a 1.7-fold increase in men using the placebo.
"But it's not just about time," Wyllie added. Both partners reported greater sexual satisfaction, and the men reported greater control over their ejaculation.
Fewer than 3% of the men reported side effects; one man who reported a slight loss of sensation and one complained of slight irritation. No side effect was observed in more than one subject, Wyllie said.
Wyllie said Plethora would submit a new drug application to the FDA before the end of the year, and he hopes for approval within a year of that.
He didn't know yet what the price would be, but said he anticipated "that it will cost less per dose than Viagra" and other erectile-dysfunction drugs.
The study was funded by Plethora. Wyllie is founder and chief technical officer of the company.