A Phase III clinical trial demonstrated that men taking Dapoxetine for the treatment of premature ejaculation ( PE ) experienced significant improvements in sexual function, including ejaculatory control, satisfaction with sexual intercourse for men and their partners, and increases in intravaginal ejaculatory latency time ( IELT ).

According to the American Urological Association, premature ejaculation may be the most common male sexual disorder.
It is estimated that PE may affect 27 percent to 34 percent of men across all age ranges, in contrast to erectile dysfunction, which is estimated to affect 10 percent to 12 percent of all men, who are usually older in age.

The phase III clinical trials studied 2,614 men with premature ejaculation aged 18-77 in monogamous sexual relationships of greater than six months.

Premature ejaculation was defined as persistent or recurrent ejaculation sooner than desired either before or shortly after penetration, typically reflecting an IELT of two minutes or less, over which the sufferer has minimal or no control.

Men in the studies were randomized to receive 30 mg or 60 mg of Dapoxetine over 12 weeks in two identical, double-blind, placebo-controlled, multicenter trials. Patients were asked to take study medication one-to-three hours before intercourse.
Participants had IELT of two minutes or less in at least 75 percent of intercourse episodes occurring during the two-week baseline run-in period prior to treatment.

The studies examined changes from baseline for mean IELT as monitored by a stopwatch; measured the subject's ejaculatory control and sexual satisfaction on a five-point scale from "very poor to very good" and measured the partner's satisfaction with sexual intercourse from "very poor to very good."

The results showed:

- Men taking Dapoxetine 30 mg and 60 mg experienced more than a three-to-four fold increase in mean IELT compared with placebo ( P < 0.0001 at 30 mg and 60 mg ). IELT increased significantly with the first dose of Dapoxetine, and increases in IELT were maintained over the 12-week study period.

- The percentage of men rating control over ejaculation as "fair to very good" increased dramatically for Dapoxetine 30 mg ( 2.5 percent to 51.8 percent ) and 60 mg ( 3.3 percent to 58.4 percent ) compared to placebo ( 3.5 percent to 26.4 percent ).

- The percentage of men rating sexual satisfaction as "good to very good" almost doubled with Dapoxetine 30 mg ( 20.2 percent to 38.7 percent ) and 60 mg ( 22.3 percent to 46.5 percent ), respectively, in comparison to placebo ( 21.6 percent to 24.6 percent ).

- The percentage of partners rating sexual satisfaction as "good to very good" almost doubled with Dapoxetine 30 mg ( 20.4 percent to 39 percent ) and 60 mg ( 24.8 percent to 47.4 percent ), respectively, compared to placebo ( 20.1 percent to 25.2 percent ).

The study also found that Dapoxetine was generally well tolerated, with most side effects of mild-to-moderate severity.
The most common adverse events reported with both 30 mg and 60 mg doses of Dapoxetine were nausea, followed by headache.

An observational study published in 2005 in The Journal of Sexual Medicine found that patient-reported outcome measures ( PROs ), such as control over ejaculation, satisfaction with sexual intercourse and distress are important factors in assessing the benefit of treatments for premature ejaculation in clinical studies. The study found that men with premature ejaculation and their partners reported higher ratings for interpersonal difficulty, lack of control over ejaculation and dissatisfaction with sexual intercourse.

Source: 100th Annual Meeting of the American Urological Association ( AUA ), 2005


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