A Double Blind, Placebo Controlled, Randomized Trial to Evaluate the Efficacy and Tolerability of On-Demand Oral Pregablin (150 mg and 75 mg) in Treatment of Premature Ejaculation

Possible pathophysiologic roles of neurotransmitter systems in men with lifelong premature ejaculation: a scoping review

INTRODUCTION

Lifelong premature ejaculation (LPE) is a subtype of premature ejaculation. Genetic research on LPE has primarily focused on neurotransmitters such as serotonin, dopamine, and norepinephrine, whereas LPE treatment studies have focused on drugs such as selective serotonin reuptake inhibitors. However, findings from genetic association and pharmacotherapeutic studies have been inconsistent.

OBJECTIVES

To provide a quality overview of neurobiological targets that are potentially associated with LPE by investigating genetic association and pharmacotherapeutic studies.

METHODS

This scoping review was conducted per the PRISMA-ScR tool (Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews). Five databases were searched in March 2023 without timeline- or language-related restrictions.

RESULTS

After deduplication, 3949 records were obtained for review. Following screening and full-text review with citation tracking, 52 studies were included: 18 genetic and 34 pharmacotherapy studies. Serotonergic targets, such as the serotonin transporter and pre- and postsynaptic serotonergic receptors, were most often associated with LPE in genetic and pharmacotherapeutic studies. Mixed results were found among polymorphisms within genetic studies. This mechanism is in accordance with pharmacotherapeutic studies, as the highest efficacy was found for potent serotonergic antidepressants. Successful treatment was also observed with medication acting on phosphodiesterase-5 enzyme, such as tadalafil and vardenafil. Analyses of other genetic association studies did not yield any further evidence for associated targets.

CONCLUSIONS

This review is the first comprehensive scoping review on LPE. We found that serotonergic targets are most often associated with LPE, suggesting that the serotonergic pathway is a predisposing factor in LPE. Furthermore, there is some evidence for phosphodiesterase 5 inhibitors, which should be investigated. Other previously investigated neurobiological targets appear less likely to contribute to LPE. Future studies should focus on multiple targets, ideally in a genome-wide association study design.This review has been registered with the Open Science Framework (doi:10.17605/OSF.IO/JUQSD).

Traditional, Complementary and Alternative Medicines in the Treatment of Ejaculatory Disorders: A Systematic Review

Background and Objectives: Ejaculatory dysfunction (EjD) is a common male sexual disorder that includes premature ejaculation, delayed ejaculation, retrograde ejaculation, and anejaculation. Although psychological and pharmacological treatments are available, traditional, complementary, and alternative medicine (TCAM) is reportedly used. However, the clinical evidence for TCAM in EjD remains unclear. Therefore, this study aims to systematically review human clinical trials investigating the use of TCAM to treat EjD. Materials and Methods: A systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted by searching Scopus and PubMed databases. Controlled clinical trials investigating a cohort of male patients diagnosed primarily with EjD and undergoing any TCAM intervention compared to any comparison group were included. Quality of the studies was assessed using the Cochrane Risk of Bias tool for randomized controlled trials. Results: Following article screening, 22 articles were included. Of these, 21 investigated TCAM in premature ejaculation, and only 1 investigated TCAM in retrograde ejaculation. Different TCAM categories included studies that investigated lifestyle, exercise and/or physical activities (n = 7); herbal medicine supplements (n = 5); topical herbal applications (n = 4); acupuncture or electroacupuncture (n = 3); vitamin, mineral and/or nutraceutical supplements (n = 1); hyaluronic acid penile injection (n = 1); and music therapy (n = 1). Only 31.8% (n = 7) of the included studies were found to have a low risk of bias. The available studies were widely heterogenous in the TCAM intervention investigated and comparison groups used. However, the included studies generally showed improved outcomes intra-group and when compared to placebo. Conclusions: Different TCAM interventions may have an important role particularly in the management of PE. However, more studies using standardized interventions are needed.

Sexual Incentive Motivation and Copulatory Behavior in Male Rats Treated With the Adrenergic α2-Adrenoceptor Agonists Tasipimidine and Fadolmidine: Implications for Treatment of Premature Ejaculation

BACKGROUND

Premature ejaculation is the most common sexual dysfunction in young men, and it often leads to reduced relationship satisfaction and quality of life.

AIM

To determine the role of central and peripheral α₂-adrenoceptors in the control of ejaculation and sexual incentive motivation in rats.

METHODS

Sexual incentive motivation was studied in a large arena in which a male subject could choose between approaching and remaining close to a sexually receptive female or another male. Sexual behavior was studied in standard observation cages in which a male was allowed to freely interact with a receptive female for 30 minutes. Two highly selective agonists at the α₂-adrenoceptors, tasipimidine and fadolmidine, were administered before the tests. Low peripheral doses of fadolmidine have been reported to have effects mainly outside of the central nervous system, whereas at large doses also the central effects are evident.

OUTCOMES

The time spent close to the receptive female in relation to the time spent with the male and measures of ambulatory activity were obtained from the test for sexual incentive motivation, while the habitual parameters of sexual behavior were recorded with the copulation test.

RESULTS

Tasipimidine prolonged ejaculation latency and the interintromission interval at the dose of 200 µg/kg when data from fast-ejaculating rats were used. No other sexual parameter was modified. A dose of 100 µg/kg was ineffective. There was no consistent effect on sexual incentive motivation, although modest sedation was observed. Fadolmidine, a drug that does not easily penetrate the blood-brain barrier, had no effect on sexual incentive motivation at any of the doses used (3, 30, and 100 µg/kg). The largest dose had clear sedative effects. The lower doses had no systematic effect on sexual behavior, not even when only fast or very fast ejaculating males were analyzed.

CLINICAL TRANSLATION

The findings are relevant to the search for treatments for premature ejaculation that are specific enough to selectively delay ejaculation.

STRENGTHS & LIMITATIONS

The procedures used here are standard in the field and yield the most reliable data. Whether the effects observed in male rats are directly transferrable to men can only be determined through clinical studies.

CONCLUSION

The observation that drugs acting at central but not peripheral α₂-adrenoceptors prolong ejaculation latency without affecting any other parameter of sexual behavior or sexual incentive motivation suggests that this kind of drug may be suitable for treating premature ejaculation. Jyrki L., Elisa V.-A., Xi C., et al. Sexual Incentive Motivation and Copulatory Behavior in Male Rats Treated With the Adrenergic α₂-Adrenoceptor Agonists Tasipimidine and Fadolmidine: Implications for Treatment of Premature Ejaculation. J Sex Med 2021;18:1677-1689.