Background: Premature ejaculation affects 21 to 33 percent of men and is believed to be the most common type of male sexual dysfunction. The potential negative effects on quality of life can be severe for men and their partners; however, few treatments have been approved to treat the condition. Psychopharmacologic studies link premature ejaculation to diminished serotonergic neurotransmission in the pathways controlling sexual performance, so a short-acting selective serotonin reuptake inhibitor (SSRI), such as dapoxetine (not available in the United States), could be beneficial. Pryor and colleagues studied the effects of dapoxetine in men with premature ejaculation in two large multicenter trials. Unlike other SSRIs, which take two weeks or longer to reach full concentration, dapoxetine reaches its maximal serum concentration in one hour and is rapidly eliminated (its half-life is one to two hours).

The Study: Patients were randomized at 121 clinical research sites in the United States. For inclusion, participants had to be older than 18 years, to have been in a stable heterosexual relationship for at least six months, and to meet Diagnostic and Statistical Manual of Mental Disorders, 4th ed., criteria for premature ejaculation. In addition, study participants had to consider their problem severe and have intravaginal ejaculatory latency times lasting fewer than two minutes in at least 75 percent of episodes two weeks before the study. Reasons for exclusion included current SSRI or tricyclic antidepressant use, a history of a major psychiatric disorder, and other sexual or erectile dysfunction. The female partners of participants had to agree to time intravaginal ejaculatory latency and to participate in reporting data relevant to the study.

The average age of the men was 40 years; nearly 90 percent were white, and 86 to 88 percent were married. More than 70 percent said their problem was severe, and the average duration of problems with premature ejaculation was 16 years.

Patients were randomly assigned to receive 30 mg or 60 mg of dapoxetine, or placebo. They were asked to take one tablet one to three hours before sexual intercourse, and the couples were to attempt intercourse at least four times during the two-week baseline period and at least six times a month for the remainder of the 12-week study.

Results: The evaluations at four, eight, and 12 weeks included intravaginal ejaculatory latency times, and both partners assessed the quality of their sexual relationship, focusing on control and satisfaction with ejaculation (see accompanying table). Information also was collected about possible adverse effects of the medication.

Both dosages of dapoxetine significantly improved intravaginal ejaculatory latency times compared with placebo and were associated with improved satisfaction with sexual performance by patients and their partners. Both dapoxetine dosages were effective from the first time of use. Adverse effects rarely caused discontinuation of treatment but were more common in the dapoxetine groups than in the placebo group. Nausea was the most common adverse effect, reported by 20.1 percent of men assigned to the 60-mg dose and by 8.7 percent assigned to the 30-mg dose. Complete data were available for 672 patients in the placebo group, 676 in the 30-mg group, and 610 in the 60-mg group.

Conclusion: The authors conclude that on-demand dapoxetine offers an effective and generally well-tolerated treatment for severe premature ejaculation.

editor's note: It is believed that most patients with premature ejaculation avoid asking for medical help because of embarrassment, and an unknown number turn to unproven and alternative therapies of various kinds. An editorial in the same issue by Montorsi and Salonia emphasizes that most patients who seek medical care are young, well-educated men who have had severe sexual dysfunction over the course of many years.¹ They emphasize the importance of a thorough assessment to identify any physiological or psychological cause for the problem, as well as the importance of providing full and accurate information to the patient and his partner.—a.d.w.