Dapoxetine for Premature Ejaculation: An Updated Meta-Analysis of Randomized Controlled Trials

His452Tyr 5-HT2A polymorphism and intravaginal ejaculation latency time in Dutch men with lifelong premature ejaculation

Lifelong premature ejaculation (LPE) may have heritable components. Selective serotonin reuptake inhibitors have been proven effective in prolonging intravaginal ejaculation latency time (IELT). Given that serotonergic pathways are involved in the ejaculation mechanism, we aimed to investigate whether His452Tyr, also known as the C1354T (RS6314) polymorphism of the 5-HT_2A receptor, contributes to LPE pathogenesis and IELT differences among patients with LPE. Dutch Caucasian men with LPE (n = 65) attending the Outpatient Department of Neurosexology, HagaZiekenhuis for drug treatment for LPE in 2009 were selected and included in this case-control study. IELT during coitus was measured using a stopwatch, and all men were genotyped for the His452Tyr polymorphism. Analysis of variance (ANOVA) was performed to determine the association between the genotypes and IELTs. Mean IELTs with standard deviations were 29.7 (±20.9), 31.5 (±14.7), and 26.0 s, and the frequencies were 83.1%, 15.4%, and 1.5% for the CC, CT, and TT groups, respectively, with an average IELT of 29.9 s. No difference in mean IELT was observed between these groups. In the affected group, the frequencies of alleles C and T were 90.8% and 9.2%, respectively; whereas those among randomly selected European Caucasian male controls (n = 503) from the CEPH database were of 92.0% and 8.0%, respectively. No significant difference was observed between the groups. Therefore, no correlation was found between the His452Tyr polymorphism and IELT distribution in patients with LPE.

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

INTRODUCTION

Although premature ejaculation (PE) is a common sexual dysfunction, the available options for PE treatment remain unsatisfactory.

AIM

To evaluate the effect of on-demand oral pregabalin on the intravaginal ejaculation latency time (IELT).

METHOD

We conducted a multiarm double-blinded placebo-controlled randomized clinical trial that enrolled 120 patients with PE who were divided equally into 3 groups (A, B, and C). 4 patients were excluded, 39 patients received 150 mg pregabalin (group A), 39 patients received 75 mg pregabalin (group B), and 38 patients received placebo (group C). All patients were encouraged to engage in sexual relations twice per week for 2 weeks and to take the medication 1-2 hours before sexual intercourse. A stopwatch was used to evaluate IELT.

MAIN OUTCOME MEASURE

The main outcome measure are the improvement of IELT and the reported adverse events.

RESULTS

IELT significantly improved in patients who received 150 mg pregabalin, but there was no change in the other groups.

CLINICAL IMPLICATIONS

Most PE patients showed a significant improvement after receiving on-demand pregabalin (150 mg).

STRENGTH & LIMITATIONS

The strength of this study is that it is the first randomized controlled trial to evaluate the efficacy of pregabalin in treatment of PE. The main limitations were the small number of patients, IELT was the only primary outcome of the study, and the pregabalin cap can be identified by the patient.

CONCLUSION

Oral pregabalin seems to be a promising drug for additional evaluation as a new treatment for PE. More studies are needed to evaluate the suitable dose, duration, timing, and its safety profile. El Najjar MR, El Hariri M, Ramadan A, et al. 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. J Sex Med 2020;17:442-446.

Impacts of Cytochrome P450 2D6*10 Allele and a High-Fat Meal on the Pharmacokinetics of Dapoxetine in Healthy Chinese Men: A Single-Dose, Two-Treatment Study

INTRODUCTION

Factors that impact the pharmacokinetics of dapoxetine, a 5-HT selective reuptake inhibitor used for the treatment of premature ejaculation, have not been clearly identified. This study aimed to evaluate the effects of consumption of a high-fat meal and cytochrome P450 (CYP) 2D6 polymorphisms on the pharmacokinetics of dapoxetine in healthy Chinese men.

METHODS

Twenty-two healthy volunteers were enrolled and classified based on their CYP2D6 genotype. A single-dose, two-treatment (fasted and fed), two-period, one-sequence pharmacokinetic study was conducted. Plasma concentrations of the drug were determined using LC-MS. Pharmacokinetic parameters were calculated by a noncompartmental analysis.

RESULTS

The consumption of food significantly prolonged the time required for dapoxetine to reach its peak concentration and area under the concentration-time curve (AUC_0-48) (p < 0.01). Compared with that in *1/*10 and *2/*10 genotypes, the dapoxetine plasma exposure in *10/*10 individuals was notably increased. The AUC_0-48 value for *10/*10 was significantly higher than that for *1/*10 and *2/*10 (p < 0.05).

CONCLUSION

The obtained results demonstrated that a high-fat meal and the CYP2D6 *10/*10 genotype influence the pharmacokinetic properties of dapoxetine and may thus have potential clinical implications. Future studies focusing on safe dapoxetine dosing based on CYP2D6 genotyping are needed.

FUNDING

This study was partially sponsored by Xiamen Fuman Pharmaceutical Co., Ltd. The article processing charges were funded by The People's Hospital of Dujiangyan City.

Comparative efficacy and safety of phosphodiesterase-5 inhibitors with selective serotonin reuptake inhibitors in men with premature ejaculation: A systematic review and Bayesian network meta-analysis

BACKGROUND

We performed the network meta-analysis (NMA) and systematic review involved all evidence from relevant trials to compare the efficiency and safety of various types of selective serotonin reuptake inhibitors (SSRI) and phosphodiesterase-5 inhibitors (PDE5i) in patients with premature ejaculation (PE).

METHODS

We conducted comprehensive searches of peer-reviewed and grey literature. PubMed, the Cochrane Library Central Register of Controlled Trials, Embase were searched for randomized controlled trials published up to June 1, 2017. The primary outcome was intravaginal ejaculation latency time (IVELT) and adverse effects (AEs). We performed pairwise meta-analyses by random effects model and network meta-analysis by Bayesian model. We used the GRADE framework to assess the quality of evidence contributing to each network estimate.

RESULTS

Of 3046 titles and abstracts initially identified, 17 trials reporting 5739 participants were included. Considering IVELT in the NMA, paroxetine plus sildenafil and sildenafil alone are both superior to placebo (MD: 1.75, 95% CrI: 0.05 to 3.78; MD 1.43, 95% CrI 0.003 to 2.81). Sildenafil is superior to sertraline (MD: 1.63, 95% CrI: 0.10 to 2.79). Considering AEs, placebo demonstrated obviously lower risk comparing to paroxetine, sildenafil and paroxetine plus sildenafil (OR 0.20, 95% CI: 0.05 to 0.52; OR 0.23, 95% CI: 0.04 to 0.80; OR 0.45, 95% CI: 0.01 to 0.92). Compared with tadalafil plus paroxetine, dapoxetine showed significantly less AEs (OR 0.23, 95% CI 0.02 to 0.96).

CONCLUSIONS

Our study concluded that although paroxetine plus sildenafil and sildenafil alone both demonstrated significant IVELT benefit compared with placebo, significant increase of AEs risk was also observed. Furthermore, sildenafil alone was superior to sertraline in efficacy with comparable tolerability.

Dapoxetine for the treatment of premature ejaculation: a meta-analysis of randomized controlled trials with trial sequential analysis

BACKGROUND

The safety and efficacy of dapoxetine for the treatment of premature ejaculation (PE) is still controversial. Thus, we decided to conduct a meta-analysis using trial sequential analysis (TSA) to determine the sufficiency of conclusions.

OBJECTIVE

Evaluate the efficacy and safety of dapoxetine in the treatment of patients with PE and assess the reliability of the findings.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

METHODS

Electronic databases including PUBMED, EMBASE, Cochrane Library, CNKI and Wanfang data were reviewed up to July 2017. RCTs evaluating the efficacy of dapoxetine in patients with PE and reporting intravaginal ejaculatory latency time (IELT), patient global impression of change (PGIC) and/or adverse events (AEs) were included.

MAIN OUTCOME MEASURES

Mean differences between trials in efficacy for IELT, and risk ratios for PGIC and treatment-emergent AEs.

SAMPLE

8 RCTs.

RESULTS

For IELT and PGIC, significant effects were found for all doses of dapoxetine versus placebo, and similar results were obtained in subgroups of the 30-mg dose versus 60-mg dose. There were also statistically different dose-related effects on AEs. Trial sequential analysis showed that the result of our meta-analysis was confirmed and further trials are unnecessary.

CONCLUSIONS

The evidence suggests that dapoxetine may be a safe and effective drug for patients with PE.

REGISTRATION

Not registered, no published protocol.

CONFLICT OF INTEREST

No relationship with manufacturer of drug.

Emerging and investigational drugs for premature ejaculation

Over the past 20−30 years, the premature ejaculation (PE) treatment paradigm, previously limited to behavioural psychotherapy, has expanded to include drug treatment. Pharmacotherapy for PE predominantly targets the multiple neurotransmitters and receptors involved in the control of ejaculation which include serotonin, dopamine, oxytocin, norepinephrine, gamma amino-butyric acid (GABA) and nitric oxide (NO). The objective of this article is to review emerging PE interventions contemporary data on the treatment of PE was reviewed and critiqued using the principles of evidence-based medicine. Multiple well-controlled evidence-based studies have demonstrated the efficacy and safety of selective serotonin reuptake inhibitors (SSRIs) in delaying ejaculation, confirming their role as first-line agents for the medical treatment of lifelong and acquired PE. Daily dosing of SSRIs is likely to be associated with superior fold increases in IELT compared to on-demand SSRIs. On-demand SSRIs are less effective but may fulfill the treatment goals of many patients. Integrated pharmacotherapy and CBT may achieve superior treatment outcomes in some patients. PDE-5 inhibitors alone or in combination with SSRIs should be limited to men with acquired PE secondary to co-morbid ED. New on-demand rapid acting SSRIs, oxytocin receptor antagonists, or single agents that target multiple receptors may form the foundation of more effective future on-demand medication. Current evidence confirms the efficacy and safety of dapoxetine, off-label SSRI drugs, tramadol and topical anaesthetics drugs. Treatment with α1-adrenoceptor antagonists cannot be recommended until the results of large well-designed RCTs are published in major international peer-reviewed medical journals. As our understanding of the neurochemical control of ejaculation improves, new therapeutic targets and candidate molecules will be identified which may increase our pharmacotherapeutic armamentarium.