The spray, dubbed PSD502, contains the anesthetics lidocaine and prilocaine. But it doesn't deaden feeling, thanks to an ingredient in the spray that allows it to rapidly penetrate the skin, says Ira Sharlip, MD, clinical professor of urology a the University of California, San Francisco.
"It rarely causes a decrease in sensation in the penis because it is absorbed so quickly," Sharlip tells WebMD. "In men using the product, the incidence of penile anesthesia is 1% or 2%."
"There is some burning sensation in the vagina in about 5% of partners," Sharlip says. "It infrequently causes problems in female partners because it is absorbed so quickly there is little left on the skin. The risk of transfer is small."
Sharlip was one of three investigators presenting studies of PSD502 at this week's meeting of the Sexual Medicine Society of North America Inc. in San Diego. Sharlip and the other study presenters serve as consultants to Sciele Pharma Inc., which acquired the rights to PSD502 from U.K.-based Plethora Solutions Ltd.
The studies show that men using PSD502 are able to delay ejaculation about five times longer. Sharlip's study found that men who ejaculated an average 36 seconds after vaginal penetration were able to delay ejaculation for over three minutes after one month of PSD502 treatment, and for three minutes and 42 seconds after three months of treatment.
The findings confirm those of a previous study reported earlier this year.
Premature ejaculation isn't just a problem for young, inexperienced teens. Sharlip says it affects some 20% to 30% of men of all ages.
"A lot of men with PE just struggle and are very unhappy, although not everyone who has PE is unhappy about it. But many men are very disturbed and distressed by it," Sharlip says.
Many men suffering premature ejaculation are unable to delay ejaculation for much more than half a minute. Some are unable delay long enough to achieve vaginal penetration, making it difficult for them to father children.
Current treatments include off-label use of SSRI antidepressants, as delayed ejaculation is a common side effect of these drugs. But the drugs must either be taken daily -- increasing the risk of side effects -- or taken three to six hours in advance of sexual activity.
"Sex is not always that predictable," Sharlip says.
There are also topical preparations. One that is commonly used is EMLA cream, which, like PSD502, contains lidocaine and prilocaine. However, EMLA must be used with a condom or washed off prior to sex.
"I think PSD502 will attract a lot of men particularly because it has a very rapid onset of action," Sharlip says. "You put this stuff on and in five minutes you have an effect."
Sharlip says that based on the studies reported today, he hopes PSD502 will become available in a little more than a year's time.