Dapoxetine: an evidence-based review of its effectiveness in treatment of premature ejaculation

Drug Repurposing: A Leading Strategy for New Threats and Targets

Less than 6% of rare illnesses have an appropriate treatment option. Repurposed medications for new indications are a cost-effective and time-saving strategy that results in excellent success rates, which may significantly lower the risk associated with therapeutic development for rare illnesses. It is becoming a realistic alternative to repurposing "conventional" medications to treat joint and rare diseases considering the significant failure rates, high expenses, and sluggish stride of innovative medication advancement. This is due to delisted compounds, cheaper research fees, and faster development time frames. Repurposed drug competitors have been developed using strategic decisions based on data analysis, interpretation, and investigational approaches, but technical and regulatory restrictions must also be considered. Combining experimental and computational methodologies generates innovative new medicinal applications. It is a one-of-a-kind strategy for repurposing human-safe pharmaceuticals to treat uncommon and difficult-to-treat ailments. It is a very effective method for discovering and creating novel medications. Several pharmaceutical firms have developed novel therapies by repositioning old medications. Repurposing drugs is practical, cost-effective, and speedy and generally involves lower risks when compared to developing a new drug from the beginning.

Optimization of taste-masked dapoxetine oral thin films using factorial design: in vitro and in vivo evaluation

Dapoxetine HCl is used for the treatment of premature ejaculation. Dapoxetine is primarily metabolized in the liver and kidney and its metabolites are inactive; resulting in reduced bioavailability. Also, one of the commonly encountered issues in the oral dapoxetine formulae is its bitter taste. Thus, the objective of this study was to develop and to optimize novel dapoxetine taste-masked oral thin films (OTFs), to offer a faster dissolution rate, rapid release pattern, lower liver metabolism, and better patient compliance. To achieve our goal, the applicability of either pullulan or maltodextrin as strip forming polymers were investigated in the preparation of (OTFs), while glycerol was used as a plasticizer. Also, the physicochemical characteristics of dapoxetine in a resinate complex with AmberLite^TM -IRP69 as taste masking were evaluated. Furthermore, a 2³ factorial design was used to study and to optimize the effect of the independent variables (strip forming polymer (X₁), glycerol (X₂) and AmberLite^TM (X₃) amounts) on the disintegration time (Y₁), degree of elongation (Y₂), and degree of in vitro drug release in phosphate buffer pH 6.8 at 5 minutes (Q5min, Y₃) as responses. P2 batch (OTF) (pullulan 96 mg, glycerol 12 mg, AmberLite^TM 32 mg, and dapoxetine 30 mg) was identified as an optimized formulation showing an in vitro disintegration time 9.33 s, 35.56% elongation, and 91.43% Q5min; excellent in vivo disintegration time; good overall taste acceptability and stable resinate complex.

Mitigation of Rheumatic Arthritis in a Rat Model via Transdermal Delivery of Dapoxetine HCl Amalgamated as a Nanoplatform: In vitro and in vivo Assessment

Purpose

Dapoxetine HCl (DH), a selective serotonin reuptake inhibitor, may be useful for the treatment of rheumatic arthritis (RA). The purpose of this study was to investigate the therapeutic efficacy of transdermal delivery of DH in transethosome nanovesicles (TENVs). This novel delivery of DH may overcome the drawbacks associated with orally administered DH and improve patient compliance.

Methods

DH-TENV formulations were prepared using an injection- sonication method and optimized using a 3³ Box-Behnken-design with Design Expert^® software. The TENV formulations were assessed for entrapment efficiency (EE-%), vesicle size, zeta potential, in vitro DH release, and skin permeation. The tolerability of the optimized DH-TENV gel was investigated using a rat skin irritation test. A pharmacokinetic analysis of the optimized DH-TENV gel was also conducted in rats. Moreover, the anti-RA activity of the optimized DH-TENV gel was assessed based on the RA-specific marker anti-cyclic cirtullinated peptide antibody (anti-CCP), the cartilage destruction marker cartilage oligomeric matrix protein (COMP) and the inflammatory marker interleukin-6 (IL-6). Level of tissue receptor activator of nuclear factor kappa-Β ligand (RANKL) were also assessed.

Results

The optimized DH-TENV formulation involved spherical nanovesicles that had an appropriate EE- % and skin permeation characteristic. The DH-TENV gel was well tolerated by rats. The pharmacokinetics analysis showed that the optimized DH-TENV gel boosted the bioavailability of the DH by 2.42- and 4.16-fold compared to the oral DH solution and the control DH gel, respectively. Moreover, it significantly reduced the serum anti-CCP, COMP and IL-6 levels and decreased the RANKL levels. Furthermore, the DH-TENV gel attenuated histopathological changes by almost normalizing the articular surface and synovial fluid.

Conclusion

The results indicate that DH-TENVs can improve transdermal delivery of DH and thereby alleviate RA.

Zein-alpha lipoic acid-loaded nanoparticles to enhance the oral bioavailability of dapoxetine: optimization and clinical pharmacokinetic evaluation

Background

Premature ejaculation (PE) is the most common type of male sexual disorder with important psychological consequences. Dapoxetine (DPX), a recently approved drug for the treatment of PE, suffers from low bioavailability with large variability that ranges from 15–76% (mean 42%) after oral administration. The objective of this study is to optimize the parameters for the preparation of DPX-Zein-alpha lipoic acid (ALA) nanoparticles (NPs) to improve the bioavailability of DPX and consequently decrease therapeutic dose and adverse effect, leading to patient satisfaction and compliance.

Methods

We investigated the effect of ALA concentration, PVA concentration and stirring rate on nanoparticle size (Y₁), zeta potential (Y₂), initial DPX release (Y₃) and cumulative DPX release (Y₄). In addition, in vivo pharmacokinetic study was performed for the optimized DPX formulation on human healthy volunteers compared with marketed DPX tablet.

Results

The optimized DPX-loaded NPs showed Y₁, Y₂, Y₃, and Y₄ of 159.24 nm, 19.14 mV, 25.31% and 95.9 %, respectively. A single oral dose of 30 mg of optimized DPX-loaded NPs to human volunteers resulted in 2-fold improvement of AUC (1376.145±339.592 vs 709.178±146.307 in DPX), 4-fold increase in t_max (2.5±0.314 vs 0.583±0.144), prolongation of MRT (7.637±1.373 compared to 6.031±1.826 h), but with reduction in t_1/2 (5.283±1.077 vs 8.452±2.813).

Conclusion

The clinical findings suggest 194% enhancement of relative bioavailability of the optimized DPX-loaded NPs, potentially leading to a decrease in therapeutic dose and associated side effects in the treatment of PE.

Contemporary Vistas in Geriatric Sexuality

There is a substantial increase in the total geriatric population worldwide. This change in demography calls for a greater, deeper, and thorough understanding of elderly and age-related issues. Even though sexuality is a basic and vital driving force, human sexuality, especially elderly sexuality, is frequently misunderstood. Many myths and misconceptions regarding elderly sexuality exist which need attention. Contrary to the popular belief, studies reveal that sexual life continues to be an important aspect in later life and is often viewed by elderly as an expression of love, passion, affection, admiration, and loyalty. Various factors play a role in elderly sexuality including that of bio-psycho-social factors, changes in the body, presence of comorbid conditions along with sexual disorders. Sexual disorders, if present, should be treated and addressed adequately.

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.

Pharmacological interventions for premature ejaculation: a mixed-treatment comparison network meta-analysis of randomized clinical trials

Premature ejaculation (PE) is the most common sexual dysfunction in men. The present study is a network meta-analysis of drugs used for treating PE. Electronic databases were searched for randomized controlled trials comparing medical interventions with either placebo or with other active drugs in patients with PE. Inverse variance heterogeneity model was used for mixed-treatment comparisons. Intravaginal ejaculatory latency time (IELT) and adverse events were the main outcome measures. A total of 44 studies were included in the meta-analysis. Dapoxetine 30 and 60 mg, tadalafil, sildenafil, paroxetine with sildenafil, topical lidocaine, dapoxetine 30 mg with mirodenafil, vardenafil, fluoxetine, and tadalafil, pindolol with paroxetine, tramadol, topical lidocaine with tadalafil, paroxetine with tadalafil, and topical eutectic mixture of local anesthetics were associated with a significant increase in IELT. Similarly, dapoxetine 60 mg, venlafaxine, fluoxetine, tramadol at 25, 50, and 100 mg, and combined fluoxetine and tadalafil were associated with an increased risk of adverse events. Dapoxetine 30 mg has a high likelihood of being the "best" in the interventional pool. Dapoxetine at 30 mg could be used as the first-line agent in the management of PE.

Novel instantly-dispersible nanocarrier powder system (IDNPs) for intranasal delivery of dapoxetine hydrochloride: in-vitro optimization, ex-vivo permeation studies, and in-vivo evaluation

Dapoxetine (D) suffers from poor oral bioavailability (42%) due to extensive metabolism in the liver. The aim of this study was to enhance the bioavailability of D via preparing instantly-dispersible nanocarrier powder system (IDNPs) for intranasal delivery of D. IDNPs were prepared using the thin film hydration technique, followed by freeze-drying to obtain easily reconstituted powder providing rapid and ready method of administration. The produced nanocarrier systems were evaluated for drug content, entrapment efficiency percentage, particle size, polydispersity index, zeta potential, and drug payload. The optimized nanocarrier system was morphologically evaluated via transmission electron microscopy and the optimized freeze-dried IDNPs were evaluated for ex-vivo permeation and in-vivo pharmacokinetic studies in rabbits following intranasal and oral administration. The relative bioavailability of D after intranasal administration of freeze-dried IDNPs was about 235.41% compared to its corresponding oral nanocarrier formulation. The enhanced D permeation and improved bioavailability suggest that IDNPs could be a promising model for intranasal delivery of drugs suffering from hepatic first pass effect.

Discontinuation of Dapoxetine Treatment in Patients With Premature Ejaculation: A 2-Year Prospective Observational Study

Introduction

Although dapoxetine is the only oral pharmacologic agent approved for the treatment of premature ejaculation (PE) and is very effective, the discontinuation rate is high.

Aim

To assess the discontinuation rate of patients with PE and the reasons for discontinuation in real-world practice.

Methods

In total, 182 consecutive patients were enrolled. Type of PE, self-estimated intravaginal ejaculation latency time, and medical history were evaluated in all patients who also completed the erectile function domain of the International Index of Erectile Function (IIEF). Visits were scheduled 1, 3, 6, 12, and 24 months after initiation of therapy; treatment status and the reasons for discontinuation in those who did discontinue were checked. The relations of discontinuation rates were compared with various parameters and the time to discontinuation after treatment commencement.

Results

Of all patients, 9.9% continued treatment to 2 years. The cumulative discontinuation rates at 1, 3, 6, 12, and 24 months were 26.4%, 61.6%, 79.1%, 87.3%, and 90.1%, respectively. Moreover, 79.1% of all patients discontinued treatment within 6 months. After 12 months, the discontinuation rate decreased sharply. The reasons for discontinuation were cost (29.9%), disappointment that PE was not curable and that dapoxetine was required every time sexual intercourse was contemplated (25%), side effects (11.6%), perceived poor efficacy (9.8%), a search for other treatment options (5.5%), and unknown (18.3%). Patients with acquired PE (vs lifelong PE), with intravaginal ejaculation latency time longer than 2 minutes before treatment, on phosphodiesterase type 5 inhibitors, and with IIEF erectile function scores lower than 26 tended to discontinue early and thus exhibited high dropout rates.

Conclusion

The treatment discontinuation rate of dapoxetine was very high. The main reasons for discontinuation were the cost and disappointment that treatment was required every time adequate sexual function was required.

Park HJ, Park NC, Kim TN, et al. Discontinuation of Dapoxetine Treatment in Patients With Premature Ejaculation: A 2-Year Prospective Observational Study. Sex Med 2017;5:e99–e105.

Efficacy and safety of dapoxetine in treatment of premature ejaculation: an evidence-based review

BACKGROUND

Premature ejaculation (PE) is a major issue in male sexual health, with a global prevalence estimated to be between 20% and 40%, making it the most common sexual dysfunction in men. PE causes distress and reduced quality of life for patients and has a negative impact on interpersonal relationships. Historically, it has been treated with cognitive therapy, behavioural methods and off-label use of selective serotonin reuptake inhibitors (SSRIs) usually used to treat depression and other psychological disorders. Dapoxetine is the only SSRI specifically designed to treat PE.

MECHANISM OF ACTION

Dapoxetine hydrochloride is a potent inhibitor of serotonin reuptake transporters. Dapoxetine is suited for 'on-demand' treatment of PE because of its rapid absorption and short initial half-life.

EFFICACY

Evidence from published studies showed that dapoxetine 30 mg or 60 mg taken 'on-demand' results in a significant increase in intravaginal ejaculatory latency time (IELT) when compared with placebo. Most patient-reported outcomes are clearly improved relative to placebo following dapoxetine therapy, indicating greater control over ejaculation, more satisfaction with intercourse, less ejaculation-related distress and significantly reduced interpersonal difficulties.

SAFETY

The most common adverse events with dapoxetine are nausea, dizziness, somnolence, headache, diarrhoea and insomnia. Usually they do not lead to drug discontinuation.

CONCLUSION

Dapoxetine is the only effective and safe available on-label oral treatment for PE, and its use can result in better quality of life for the patient and their sexual partner.

Effects of 22 novel CYP2D6 variants found in Chinese population on the metabolism of dapoxetine

Background

CYP2D6 is one of the most important members of the cytochrome P450 superfamily. Its genetic polymorphism significantly influences the efficacy and safety of some drugs, which might cause adverse effects and therapeutic failure.

Methods and results

The aim of this research was mainly to explore the catalytic activities of 22 newly reported CYP2D6 isoforms (2D6*87, *88, *89, *90, *91, *92, *93, *94, *95, *96,*97, *98, *R25Q, F164L, E215K, F219S, V327M, D336N, V342M, R344Q, R440C, R497C) on dapoxetine in vitro. The research was designed with an appropriate incubation system in test tubes and carried out in the constant temperature water. Through detecting its two metabolites desmethyldapoxetine and dapoxetine-N-oxide, the available data were obtained to explain the influence of CYP2D6 polymorphism on the substrate drug dapoxetine. As a result, the intrinsic clearance (V_max/K_m) values of most variants were significantly altered when compared with the counterpart of CYP2D6*1, with most of these variants exhibiting either reduced V_max and/or increased K_m values. For dapoxetine demethylation pathway (which produces desmethyldapoxetine), 2D6*89 and E215K exhibited no markedly decreased relative clearance of 92.81% and 97.70%, respectively. The relative clearance of rest 20 variants exhibited decrease in different levels, ranging from 20.44% to 90.90%. For the dapoxetine oxidation pathway (which produces dapoxetine-N-oxide), the relative clearance values of three variants, 2D6*90, *94, and V342M, exhibited no markedly increased relative clearance of 106.17%, 107.78%, and 109.98%, respectively; the rest 19 variants exhibited significantly decreased levels ranging from 27.56% to 84.64%. In addition, the kinetic parameters of two CYP2D6 variants (2D6*92 and 2D6*96) could not be detected, due to the defect of the CYP2D6 gene.

Conclusion

As the first report of all aforementioned alleles for dapoxetine metabolism, these data may help in the clinical assessment of the metabolic elimination of dapoxetine and may provide fundamental information for further clinical studies.

Dapoxetine and the treatment of premature ejaculation

Background

Premature ejaculation (PE) is the most common male sexual complaint. Off-label oral selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for the treatment of PE. Dapoxetine is a short-acting SSRI specifically designed for on-demand use. The objective of this communication is to summarize the clinical and physiological evidence regarding the role of the serotonergic pathway and specifically dapoxetine in the treatment of PE.

Methods

A PubMed search was conducted on articles reporting data on dapoxetine for the treatment of PE. Articles describing the pathophysiology and treatment options for PE were additionally included for review.

Results

The etiology of PE is multi-factorial in nature. There are many treatment options for PE such as psychological/behavioral therapy, topical anesthetic agents, phosphodiesterase type 5 (PDE-5) inhibitors, and tramadol hydrochloride. SSRIs play a major role in PE treatment. Animal and clinical studies in addition to its pharmacokinetic document dapoxetine’s clinical efficacy and safety for on-demand treatment of PE.

Conclusions

Dapoxetine demonstrates clinical efficacy and a favorable side effect profile. Dapoxetine is currently the oral drug of choice for on-demand treatment of PE.

Interventions to treat premature ejaculation: a systematic review short report

BACKGROUND

Premature ejaculation (PE) is commonly defined as ejaculation with minimal sexual stimulation before, on or shortly after penetration and before the person wishes it. PE can be either lifelong and present since first sexual experiences (primary), or acquired (secondary), beginning later (Godpodinoff ML. Premature ejaculation: clinical subgroups and etiology. J Sex Marital Ther 1989;15:130-4). Treatments include behavioural and pharmacological interventions.

OBJECTIVE

To systematically review evidence for clinical effectiveness of behavioural, topical and systemic treatments for PE.

DATA SOURCES

The following databases were searched from inception to 6 August 2013 for published and unpublished research evidence: MEDLINE; EMBASE; Cumulative Index to Nursing and Allied Health Literature; The Cochrane Library including the Cochrane Systematic Reviews Database, Cochrane Controlled Trials Register, Database of Abstracts of Reviews of Effects and the Health Technology Assessment database; ISI Web of Science, including Science Citation Index, and the Conference Proceedings Citation Index-Science. The US Food and Drug Administration website and the European Medicines Agency (EMA) website were also searched.

METHODS

Randomised controlled trials (RCTs) in adult men with PE were eligible (or non-RCTs in the absence of RCTs). RCT data were extrapolated from review articles when available. The primary outcome was intravaginal ejaculatory latency time (IELT). Data were meta-analysed when possible. Other outcomes included sexual satisfaction, control over ejaculation, relationship satisfaction, self-esteem, quality of life, treatment acceptability and adverse events (AEs).

RESULTS

A total of 103 studies (102 RCTs, 65 from reviews) were included. RCTs were available for all interventions except yoga. The following interventions demonstrated significant improvements (p < 0.05) in arithmetic mean difference in IELT compared with placebo: topical anaesthetics - eutectic mixture of local anaesthetics (EMLA(®), AstraZeneca), topical eutectic mixture for PE (Plethora Solutions Ltd) spray; selective serotonin reuptake inhibitors (SSRIs) - citalopram (Cipramil(®), Lundbeck), escitalopram (Cipralex(®), Lundbeck), fluoxetine, paroxetine, sertraline, dapoxetine (Priligy(®), Menarini), 30 mg or 60 mg; serotonin-noradrenaline reuptake inhibitors - duloxetine (Cymbalta(®), Eli Lilly & Co Ltd); tricyclic antidepressants - inhaled clomipramine 4 mg; phosphodiesterase-5 (PDE5) inhibitors - vardenafil (Levitra(®), Bayer), tadalafil (Cialis(®), Eli Lilly & Co Ltd); opioid analgesics - tramadol (Zydol SR(®), Grünenthal). Improvements in sexual satisfaction and other outcomes compared with placebo were evident for SSRIs, PDE5 inhibitors and tramadol. Outcomes for interventions not compared with placebo were as follows: behavioural therapies - improvements over wait list control in IELT and other outcomes, behavioural therapy plus pharmacotherapy better than either therapy alone; alpha blockers - terazosin (Hytrin(®), AMCO) not significantly different to antidepressants in ejaculation control; acupuncture - improvements over sham acupuncture in IELT, conflicting results for comparisons with SSRIs; Chinese medicine - improvements over treatment as usual; delay device - improvements in IELT when added to stop-start technique; yoga - improved IELT over baseline, fluoxetine better than yoga. Treatment-related AEs were evident with most pharmacological interventions.

LIMITATIONS

Although data extraction from reviews was optimised when more than one review reported data for the same RCT, the reliability of the data extraction within these reviews cannot be guaranteed by this assessment report.

CONCLUSIONS

Several interventions significantly improved IELT. Many interventions also improved sexual satisfaction and other outcomes. However, assessment of longer-term safety and effectiveness is required to evaluate whether or not initial treatment effects are maintained long term, whether or not dose escalation is required, how soon treatment effects end following treatment cessation and whether or not treatments can be stopped and resumed at a later time. In addition, assessment of the AEs associated with long-term treatment and whether or not different doses have differing AE profiles is required.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005289.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The role of dapoxetine hydrochloride on-demand for the treatment of men with premature ejaculation

Premature ejaculation (PE) is the most common male sexual dysfunction. Dapoxetine hydrochloride, belonging to a class of drugs known as selective serotonin reuptake inhibitors or, was the first drug originally approved for the on-demand treatment of men with PE. We aimed to compare the intravaginal ejaculatory latency time (IELT), patient-reported global impression of change (PGIC), and adverse effect (AE) incidence associated with the use of dapoxetine (30 mg and 60 mg) versus placebo, and evaluate the differences in administering 60 mg versus 30 mg as on-demand medical oral therapy for the treatment of PE via a literature review and meta-analysis. Relevant randomized controlled trials (RCTs) were identified from PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (Cochrane Library) databases. Ultimately, a total of seven RCTs with 8039 patients were included. Our meta-analysis demonstrated that dapoxetine (in the 30 mg and 60 mg subgroup) resulted in significantly higher IELT, PGIC, and AE incidence relative to the placebo, with higher proportions observed for 60 mg versus 30 mg of dapoxetine administration. The most common AEs were mild and tolerable. We conclude that dapoxetine (particularly the 60 mg dosage) may be considered a safe and effective drug for patients with PE.

Further definition on the multiple partner choice arena: a potential animal model for the study of premature ejaculation

INTRODUCTION

The multiple partner choice arena (MPCA) is an experimental setup in which male rats display a significant shortening of ejaculation latency, which is the main characteristic of premature ejaculation (PE) in men. Thus, the MPCA is a potential animal model for PE.

AIM

In this study, we further analyze whether the features of the MPCA satisfy the validity criteria for it to be considered an animal model as well as the possible participation of the serotoninergic system in the faster ejaculation exhibited by male rats in the MPCA.

METHODS

In Experiment 1, male rats were tested in a standard arena to assess their sexual behavior, then were assessed 1 week later in the MPCA. Another group was first tested in the MPCA, then in a standard arena. In Experiment 2, male rats divided into two groups were treated daily with WAY-100635 (5-HT(1A) antagonist) or vehicle for 15 days. In each group, half of the subjects were tested in a standard arena and half were tested in the MPCA on days 1, 8, and 15 of treatment.

MAIN OUTCOME MEASURES

Number of intromissions and intromission and ejaculation latencies were the main outcome measures.

RESULTS

In Experiment 1, males tested in the MPCA ejaculated significantly faster, regardless of the order in which they were evaluated in both arenas. In Experiment 2, the administration of WAY-100635 increased intromission and ejaculation latencies, and the number of intromissions in the MPCA.

CONCLUSIONS

The results obtained in the MPCA support its use as an animal model for PE evaluation.

Dapoxetine for premature ejaculation

Premature ejaculation, also referred to as rapid or early ejaculation, is a poorly understood disorder with no single, widely-recognised, evidence-based definition. Studies based on patient self-reporting indicate that premature ejaculation is a common complaint with estimated prevalence ranging from 4%-39% of men in the general community.(1) However, a lack of an accurate validated definition has made comparison of the results of such studies difficult.(2) In addition, perception of normal ejaculatory latency varies by country and differs when assessed by the patient or their partner.(3) ▾Dapoxetine (Priligy-A. Menarini Farmaceutica Internazionale SRL), a short-acting selective serotonin reuptake inhibitor (SSRI) is the first drug to be licensed in the UK for on-demand management of diagnosed premature ejaculation.(4) In this article we review the evidence for dapoxetine and discuss some of the challenges associated with its introduction.

Efficacy and safety of dapoxetine in men with premature ejaculation and concomitant erectile dysfunction treated with a phosphodiesterase type 5 inhibitor: randomized, placebo-controlled, phase III study

INTRODUCTION

Men with comorbid erectile dysfunction (ED) and premature ejaculation (PE) may be concomitantly prescribed a phosphodiesterase type 5 (PDE5) inhibitor and dapoxetine.

AIM

Evaluate efficacy and safety of dapoxetine 30 mg and 60 mg on demand (prn) in men with PE and ED who were being treated with PDE5 inhibitors.

METHODS

This randomized, double-blind, placebo-controlled, flexible-dose, multicenter study enrolled men ≥18 years who met diagnostic criteria for PE including intravaginal ejaculatory latency time (IELT) of ≤2 minutes in ≥75% of sexual intercourse episodes; were on stable regimen of a PDE5 inhibitor; and had International Index of Erectile Function-erectile function domain score ≥21. Subjects received placebo, dapoxetine 30 mg, or dapoxetine 60 mg prn (1-3 hours before intercourse) for 12 weeks.

MAIN OUTCOME MEASURE

Stopwatch-measured average IELT, Clinical Global Impression of Change (CGIC) in PE, Premature Ejaculation Profile (PEP), and treatment-emergent adverse events (TEAEs).

RESULTS

Of 495 subjects randomized, 429 completed the study. Arithmetic mean average IELT significantly increased with dapoxetine vs. placebo at end point (5.2 vs. 3.4 minutes) and weeks 4, 8, and 12 (P ≤ 0.002 for all). Men who described their PE at least "better" using the CGIC were significantly greater with dapoxetine vs. placebo at end point (56.5% vs. 35.4%) and weeks 4, 8, and 12 (P ≤ 0.001 for all). Significantly better outcomes were also reported with dapoxetine vs. placebo on PEP measures. Incidence of TEAEs was 20.0% and 29.6% in placebo- and dapoxetine-treated subjects, respectively (P = 0.0135). TEAEs led to discontinuation in 1.6% of subjects in both groups. Most frequent TEAEs were known adverse drug reactions of dapoxetine treatment including nausea (9.2%), headache (4.4%), diarrhea (3.6%), dizziness (2.4%), and dizziness postural (2.4%).

CONCLUSIONS

In men with PE and comorbid ED on a stable regimen of PDE5 inhibitor, dapoxetine provided meaningful treatment benefit and was generally well tolerated.