Dapoxetine, a drug currently under investigation for the treatment of premature ejaculation, provides significant improvement in the sexual function of men and their sexual partners, according to the results of a recent multinational study.
In the 22-country, 25-week, phase III clinical trial, more than 1,000 men and their female partners were recruited and randomized to receive either 30 mg or 60 mg of dapoxetine or placebo to be taken on demand 1 to 3 hours prior to sexual intercourse. Improvement in their sexual functioning was recorded.
Male and female versions of the premature ejaculation profile (PEP) questionnaires were completed by the respective participants and were analyzed by researchers, with particular attention to responses to four main items: perception of the man's control over ejaculation, male or female distress related to the rapidity of ejaculation, male or female satisfaction with intercourse, and interpersonal difficulty associated with the ejaculation.
"This is probably the first study that has considered the effects/the benefit of pharmacologic treatment of PE on the female partner," Jacques Buvat MD, director of the Centre d'Etude et de Traitement de la Pathologie de l'Appareil Reproducteur et de la Psychosomatique (CETPARP) in Lille, France, and lead author of the study. "Several recent studies based on specially designed questionnaires have shown the negative impact of PE on the partner is very important, and probably as important as in the male.
"In this study, dapoxetine has been shown not only to improve the sexual performance of the male, but also has been shown to improve the overall sexual and psychological experience of the female partner."
At baseline, less than 5% of female participants reported that their male partner's control over ejaculation was "good" or "very good." At the end of the study, this percentage increased to 25% and 32.3% with dapoxetine, 30 mg and 60 mg, respectively (vs. 14.4% with placebo).
In addition, less than 16% of female partners reported "good" or "very good" satisfaction with sexual intercourse at baseline. This percentage increased at the end of the study to 33.8% and 39.1% for female partners of men who received dapoxetine, 30 mg and 60 mg, respectively (vs. 19.4% with placebo).
Results also showed decreases in personal distress and interpersonal difficulties related to ejaculation compared to placebo reported by those females whose male partners received dapoxetine, 30 mg and 60 mg.
"Premature ejaculation is caused by a combination of biological and psychological factors, probably including defects in serotonin signals from the brain, which means that it may be improved with pharmacotherapy. By improving control during sex, dapoxetine has been shown to help men and their partners experience greater sexual satisfaction and reduce personal distress and interpersonal difficulties," Dr. Buvat explained.
Potential side effects
Dr. Buvat said that, in the future, it would be recommended to first prescribe 30 mg of dapoxetine for men with PE and only then move to 60 mg if the results are less than expected. This recommendation is primarily due to the potential adverse events associated with the drug, such as dizziness, headache, diarrhea, and particularly nausea. These adverse events are rarely severe, and are more commonly seen in patients taking the 60-mg dose; however, these events did not cause many participants to discontinue the study.
"Although positive placebo effects were seen in this study, it is clear that the effects of dapoxetine were at least three times higher than [those of] placebo," Dr. Buvat said.
Dapoxetine, which is not currently FDA-approved for use in the United States, is currently the only drug that has been developed specifically to combat PE. Other medications, such as selective serotonin reuptake inhibitors, also have been used, but according to Dr. Buvat, their efficacy has not been comparable to that of dapoxetine. Further, SSRIs may have more serious side effects not seen with dapoxetine, such as thoughts of suicide in young people.
In the present study, the scores for depression and anxiety did not change after treatment with dapoxetine, Dr. Buvat pointed out.
Dr. Buvat is an adviser and investigator for Johnson & Johnson.