Topical lidocaine–prilocaine spray for the treatment of premature ejaculation: a proof of concept study

Abstract

Premature ejaculation (PE) is the most common sexual dysfunction in men. Since heightened sensitivity of the glans is implicated in PE, it seems reasonable that reducing this sensitivity could have a delaying effect on intravaginal ejaculation latency time (IVELT) without adversely affecting the sensation of ejaculation. We have developed a local anesthetic combination, in a metered-dose aerosol delivery system, that delivers lidocaine and prilocaine in base form without organic solvents. The drug can be easily removed prior to vaginal penetration, circumventing the need for a condom that most patients find undesirable. Herein, we report on a prospective open-label pilot study investigating the safety and efficacy of this novel delivery system for topical local anesthetic to the glans penis aimed at prolonging the IVELT in patients who self-reported having PE. This was an open-label prospective pilot study. The lidocaine-prilocaine (LP) aerosol delivered 7.5 mg lidocaine and 2.5 mg prilocaine, both in base form, per actuation. A total of 14 men who had been referred to urology clinics with the problem of PE were recruited. Consent was obtained from both subjects and their partners. Couples were asked to time their IVELT without treatment on one encounter, and then on five subsequent encounters were asked to apply the spray to the glans penis, leave on for 10-15 min, wipe off carefully before intercourse. The IVELT was timed with a stopwatch and then both partners were asked to rate their individual satisfaction relative to baseline without treatment. They were also asked to document any adverse events or comments. In all, 11 patients completed the study. The average IVELT increased from 1 min:24 s to 11 min:21 s (P ¼ 0.008) representing an average eight-fold increase. No subjects experienced a decrease in IVELT. The average satisfaction score for both subjects and partners was 1.0; on a scale where À1 was worse, 0 the same, +1 better and +2 much better. Topical LP spray, applied to the glans penis 15 min before intercourse, prolongs ejaculation time significantly and improves sexual satisfaction in both men with PE and their partners. The glandular numbness, noticed in only two cases, did not adversely affect the quality of the orgasm. Occasionally, a patient reported difficulty maintaining an erection while waiting the required 15 min between application of the spray and the initiation of intercourse.

The role of local anaesthetics in premature ejaculation

“…The local anaesthetic cream formulations require application 5 -20 min before intercourse whereas the aerosol preparation (TEMPE) can be applied 5 min before. It is easy to administer, remaining adherent to the glans penis after application and is less likely to penetrate intact keratinized skin or cause anaesthesia of the shaft of the penis [ 10,20 ] .…”

“…The metered-dose spray-delivery system allows the desensitising agents, importantly in the optimal un-ionized form, to be deposited in a dose-controlled, concentrated fi lm on the glans penis, which can then penetrate the glans within 5 -10 min [ 20 ] . The eutectic mixture is slower to penetrate intact keratinized skin and as such is not likely to anaesthetise the shaft of the penis or the hands [ 21 ] .…”

“…In the fi rst open label study [ 20 ] , 11 subjects recorded stopwatch-timed IELTs at baseline and on fi ve subsequent encounters when using the spray 15 min before intercourse. The average IELT increased from 1.4 to 11.35 min ( P = 0.008), representing an average eight-fold increase.…”

“…The mixture is alcohol-free, so there is little risk of stinging on application, and although it is oil-free, the mixture forms a clear, slightly oily, odourless solution that remains adherent to the application site. It is easily wiped off with a damp wipe, so no condom is required [ 20 ] .…”

Current therapeutic strategies for premature ejaculation and future perspectives

“…The system delivers a 7.5-mg lidocaine base plus a 2.5-mg prilocaine base per actuation. 85 The first open-label pilot study involved 11 cases in which the IELT was recorded by stopwatch. Using the spray 15 min before intercourse, the average IELT increased from 1.40 to 11.35 min (P50.008).…”