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

[Recommendations for the treatment of premature ejaculation]

OBJECTIVES

The Post-University Interdisciplinary Association of Sexology (AIUS) has brought together a panel of experts to develop French recommendations for the management of premature ejaculation.

METHODS

Systematic review of the literature between 01/1995 and 02/2022. Use of the clinical practice guidelines (CPR) method.

RESULTS

We recommend giving all patients with PE psychosexological counseling, and whenever possible combining pharmacotherapies and sexually-focused cognitive-behavioral therapies, involving the partner in the treatment process. Other sexological approaches could be useful. We recommend the use of dapoxetine as first-line, on-demand oral therapy for primary and acquired PE. We recommend the use of lidocaine 150mg/mL/prilocaine 50mg/mL spray as local treatment for primary PE. We suggest the combination of dapoxetine and lidocaine/prilocaine in patients insufficiently improved by monotherapy. In patients who have not responded to treatments with marketing authorisation, we suggest using an off-label SSRI, preferably paroxetine, in the absence of a contraindication. We recommend treating ED before PE in patients with both symptoms. We do not recommend using α-1 blockers or tramadol in patients with PE. We do not recommend routine posthectomy or penile frenulum surgery for PE.

CONCLUSION

These recommendations should contribute to improving the management of PE.

Changes of insular function in lifelong premature ejaculation patients before and after SSRI administration

OBJECTIVE

Lifelong premature ejaculation (PE) is regarded as one of the most common male sexual dysfunction. We aimed to detect whether insula-related brain functional networks are altered in lifelong PE patients and whether such alterations are "normalised" after selective serotonin reuptake inhibitors (SSRI) administration.

METHODS

Twenty-three drug-naive lifelong PE patients and 30 healthy controls (HC) were recruited in current study. All subjects underwent resting-state functional magnetic resonance imaging (fMRI) scan at first. One hour after dapoxetine administration, all patients underwent fMRI scanning again. The degree centrality (DC), amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) analysis, and ROI-based functional connectivity (FC) analysis were applied to calculate the abnormalities in insula-related functions among three groups.

RESULTS

Compared to HC group, PE patients at baseline showed significantly altered DC, ALFF, and ReHo value of the bilateral insula, which subsequently showed a "normalised" trend after dapoxetine administration. Additionally, compared to HC group, PE patients at baseline showed significantly decreased FC between insula and precentral gyrus, inferior frontal gyrus, middle/inferior temporal gyrus, and caudate, while patients after dapoxetine administration showed increased insula-related FC in anterior cingulate cortex and decreased FC in thalamus and middle/inferior temporal gyrus. The main effects of dapoxetine were located in precentral gyrus, inferior frontal gyrus, caudate, and limbic system.

CONCLUSIONS

Our findings report altered brain mechanism of insula in lifelong PE patients and also indicate that dapoxetine can "normalise" the abnormal function of the insula to certain extent in lifelong PE patients.

Effects of One-Shot Hyaluronic Acid Injection in Lifelong Premature Ejaculation: A Pilot Study

The therapeutic management of premature lifelong ejaculation (PE) ranges from behavioral therapy to pharmacological and surgical treatments. Hyaluronic Acid (HA) injection into the glans penis is a non-surgical procedure, intended to reduce glans hypersensitivity, improving the intravaginal ejaculation latency time (IELT). HA injection can be performed through different techniques that, although safe and effective, rarely can cause local complications. In this pilot uncontrolled study, we tested the effectiveness of a new technique based on a single HA injection into the frenulum of the glans, to improve IELT in a sample of patients affected by PE. We observed a significant increase of the IELT after one (median 73.3, IQR 66.2–79.9 s) and two months (66.2, 63.1–73.9) that gradually decreased at three months, remaining still significantly higher than at baseline (34.8, 30.9–37.4). PEDT and IIEF questionnaires significantly improved compared to baseline in the first two months of follow-up (p < 0.001). In conclusion, the preliminary results emerging from this pilot uncontrolled study, highlight the effectiveness of this one-shot HA injection approach, although a larger sample and longer follow-up time are needed to standardize the procedure.

Reasons and treatment strategy for discontinuation of dapoxetine treatment in premature ejaculation patients in China: A retrospective observational study

To assess dapoxetine discontinuation rates and the reasons for discontinuation in Chinese men with premature ejaculation (PE). Information on 906 PE outpatients was obtained from the hospital information system (HIS) in 2019. Of these, 150 patients were chosen. We analysed the dapoxetine discontinuation rate and the reasons for discontinuation over a 12-week follow-up period. The mean age of all patients was 33.6 years (range = 18-55), the mean PE duration was 12.36 ± 9.45 months. The 5-item International Index of Erectile Function (IIEF-5) score was 21.51 ± 3.80. A total of 37.3% of all the patients remained on the treatment until the 12th week. The cumulative discontinuation rates at the 4th, 8th and 12th weeks were 12%, 41.3% and 62.7%, respectively. The discontinuation rates for all the patients in weeks 0-4, weeks 4-8 and weeks 8-12 were 19.1%, 46.8% and 34.0%, respectively. After 4 weeks, the discontinuation rates dropped sharply. The reasons for patients' discontinuation were as follows: overexpectation of efficacy (30.9%), relapsing after drug withdrawal (26.6%), high cost (25.5%), side effects (9.6%), fear of drug addiction (4.3%), failure of follow-up (2.1%) and choosing other treatments (1.1%). The dapoxetine treatment discontinuation rate was very high. The main reasons for discontinuation were overexpectation of efficacy and high cost.

An up-to-date overview of the pharmacotherapeutic options for premature ejaculation

INTRODUCTION

Premature ejaculation (PE) is a sexual dysfunction of unknown etiology affecting a substantial number of males and deteriorating sexual health and quality of life of the patient and his partner. Treatment still remains challenging; however, pharmacotherapy is considered the mainstay of therapy with behavioral and psychosexual interventions being particularly important as adjudicate procedures, within the context of a holistic approach.

AREAS COVERED

The authors review the literature on the available medications for PE, both officially registered and non-registered. Currently, only dapoxetine and an anesthetic spray containing lidocaine and prilocaine (Fortacin™) are officially approved, with the rest being used off-label. Herein, updated data regarding the efficacy and safety of the pharmaceutical agents are presented.

EXPERT OPINION

On-demand dapoxetine is reportedly efficacious and safe in treating lifelong PE and is the first medication to be approved for this purpose. Fortacin has also shown considerable efficacy and may be reliably used on-demand. Phosphodiesterase type 5 inhibitors (PDE5Is) have been found to be effective in the treatment of PE and are therefore recommended either as monotherapy or combined with other therapies (i.e. dapoxetine). Adverse events of any therapy should be taken under consideration. Physicians should encourage patients to discuss their needs and expectations and grade any improvement of their condition with treatment.

The upregulation of tryptophan hydroxylase-2 expression is important for premature ejaculation treatment with the selective serotonin reuptake inhibitor

BACKGROUND

Although there was some evidence to suggest that the serotonergic system in the brain played an important role in premature ejaculation (PE), tryptophan hydroxylase-2 (TPH2) is considered to be the key enzyme for the synthesis of 5-hydroxytryptamine (5-HT) and few studies have reported that brain TPH2 is involved in the regulation of ejaculation.

OBJECTIVES

This study aimed to investigate whether changes in brain TPH2 levels were associated with PE and to explore the effects of acute administration of dapoxetine on TPH2 expression in the brain of rats with rapid ejaculation.

MATERIALS AND METHODS

Based on the ejaculation frequency, the male rats were split into three groups: "rapid," "normal," and "sluggish" ejaculators. The level of 5-HT in the brain was determined by an enzyme-linked immunosorbent assay. TPH2 expression was detected by western blot analysis and immunohistochemistry.

RESULTS

The results showed that the concentration of 5-HT and the expression of TPH2 in rapid rats were the lowest, while those in sluggish rats were the highest. Correlation analysis also indicated the level of TPH2 was positively correlated with ejaculation latency (r = 0.8633, p < 0.0001) and negatively correlated with ejaculation frequency (r = -0.874, p < 0.001). In addition, dapoxetine acute administration to rapid rats resulted in upregulation of TPH2 expression in the brain.

DISCUSSION

There was an important link between the level of TPH2 and the change of ejaculation behaviors. Decreased expression of TPH2 in relevant brain regions will lead to rapid ejaculation. Moreover, the effect of dapoxetine on prolonging ejaculation may be due to the upregulation of TPH2 expression.

CONCLUSION

We found the correlation between the level of TPH2 in the brain and PE. The findings in this study will open up a novel way for future research in PE therapy.

Premature ejaculation in OSAS: Does it improve with CPAP treatment?

AIM

Premature ejaculation (PE) is a common problem in male sexual health that significantly affects the quality of life. We aimed to evaluate the association of PE with obstructive sleep apnoea syndrome (OSAS), which is characterised by chronic oxidative stress, and to assess the effects of continuous positive airway pressure (CPAP) therapy on PE.

MATERIAL AND METHODS

Sexually active men between the ages of 20 and 50 who were newly diagnosed with PE, and diagnosed with moderate or severe OSAS were included in the study. Arabic Premature Ejaculation Index (AIPE) and Intravaginal Ejection Delay Time (IELT) were questioned for the diagnosis of PE. Patients with OSAS who accepted to participate in the study were given 1 year of CPAP treatment, and AIPE and IELT were questioned again, after the treatment. The results are compared with the results of the control group.

RESULTS

In total, 80 control subjects without OSAS, 85 patients with moderate OSAS and 82 patients with severe OSAS were included in the study. There were no significant differences between the groups in terms of age, BMI or thyroid function test results. Initial IELT and AIPE scores were significantly higher in the control group compared with the OSAS groups (for the IELT, 155.63 ± 98.78 vs 96.23 ± 60.60 and 62.86 ± 40.49; for the AIPE 26.18 ± 3.88 vs 18.71 ± 3.43 and 17.85 ± 3.83). Compared with initial (pretreatment) values, both scores improved significantly in both OSAS groups after 1 year of CPAP therapy (in moderate OSAS group, 96.23 ± 60.60 vs 134.17 ± 83.43 and 18.71 ± 3.43 vs 23.25 ± 3.43 and severe OSAS group 62.86 ± 40.49 vs 112.25 ± 71.58 and 17.85 ± 3.83 vs 24.18 ± 3.53).

CONCLUSION

For the first time in literature, we determined that the presence of OSAS was associated with significantly worse IELT and AIPE scores in males with PE, and the treatment of OSAS was related to the significant improvements in both scores, in the absence of any specific treatments for PE.

Real-life use of the eutectic mixture lidocaine/prilocaine spray in men with premature ejaculation

Topical anaesthetics are considered a first-line therapy option in men with premature ejaculation (PE). A cross-sectional retrospective analysis was performed to evaluate the real-life use of the eutectic mixture of prilocaine/lidocaine spray (FORTACIN™) in a cohort of 198 white-European men who had been consecutively and prospectively seen at a single tertiary-referral andrology centre for self-reported PE and naive for previous PE treatments. Descriptive statistics was used to describe the whole cohort and the paired t-test was applied to investigate potential differences throughout a 12-month follow-up (baseline, 1, 3, 6 and 12 months). Overall, mean (SD) age was 37 (6.5) years. Of all, lifelong, acquired and subjective PE were reported in 101 (51%), 59 (29.8%) and 38 (19.2%) patients at baseline, respectively. FORTACIN™ use increased up to 6 months, with 184 (92.9%) and 128 (66.4%) men who had tried and regularly used the compound, respectively. At 12-month follow-up, 53 (26.8%) men reported a regular use of the compound. Mean Premature Ejaculation Diagnostic Tool score significantly decreased at 6 and 12 months compared to baseline (all p < 0.05). Conversely, mean IELT significantly improved at 6-month follow-up compared to baseline (all p ≤ 0.04). Overall, FORTACIN™ emerged to be a safe and effective treatment option in PE patients of various types, with almost one fourth of patients still under treatment after 12 months. Timing and dosing of the drug can deserve to be adjusted according to patient's needs and their sexual ecology.

Selective serotonin re-uptake inhibitors for premature ejaculation in adult men

BACKGROUND

Premature ejaculation (PE) is a common problem among men that occurs when ejaculation happens sooner than a man or his partner would like during sex; it may cause unhappiness and relationship problems. Selective serotonin re-uptake inhibitors (SSRIs), which are most commonly used as antidepressants are being used to treat this condition.

OBJECTIVES

To assess the effects of SSRIs in the treatment of PE in adult men.

SEARCH METHODS

We performed a comprehensive search using multiple databases (the Cochrane Library, MEDLINE, Embase, Scopus, CINAHL), clinical trial registries, conference proceedings, and other sources of grey literature, up to 1 May 2020. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included only randomized controlled clinical trials (parallel group and cross-over trials) in which men with PE  were administered SSRIs or placebo. We also considered 'no treatment' to be an eligible comparator but did not find any relevant studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently classified and abstracted data from the included studies. Primary outcomes were participant-perceived change with treatment, satisfaction with intercourse and study withdrawal due to adverse events. Secondary outcomes included self-perceived control over ejaculation, participant distress about PE, adverse events and intravaginal ejaculatory latency time (IELT). We performed statistical analyses using a random-effects model. We rated the certainty of evidence according to GRADE.

MAIN RESULTS

We identified 31 studies in which 8254 participants were randomized to receiving either SSRIs or placebo. Primary outcomes: SSRI treatment probably improves self-perceived PE symptoms (defined as a rating of 'better' or 'much better') compared to placebo (risk ratio (RR) 1.92, 95% confidence interval (CI) 1.66 to 2.23; moderate-certainty evidence). Based on 220 participants per 1000 reporting improvement with placebo, this corresponds to 202 more men per 1000 (95% CI 145 more to 270 more) with improved symptoms with SSRIs.  SSRI treatment probably improves satisfaction with intercourse compared to placebo (defined as a rating of 'good' or 'very good'; RR 1.63, 95% CI 1.42 to 1.87; moderate-certainty evidence). Based on 278 participants per 1000 reporting improved satisfaction with placebo, this corresponds to 175 more (117 more to 242 more) per 1000 men with greater satisfaction with intercourse with SSRIs. SSRI treatment may increase treatment cessations due to adverse events compared to placebo (RR 3.80, 95% CI 2.61 to 5.51; low-certainty evidence). Based 11 study withdrawals per 1000 participants with placebo, this corresponds to 30 more men per 1000 (95% CI 17 more to 49 more) ceasing treatment due to adverse events with SSRIs.  Secondary outcomes: SSRI treatment likely improve participants' self-perceived control over ejaculation (defined as rating of 'good' or 'very good') compared to placebo (RR 2.29, 95% CI 1.72 to 3.05; moderate-certainty evidence). Assuming 132 per 1000 participants perceived at least good control, this corresponds to 170 more (95 more to 270 more) reporting at least good control with SSRIs.  SSRI probably lessens distress (defined as rating of 'a little bit' or 'not at all') about PE (RR 1.54, 95% CI 1.26 to 1.88; moderate-certainty evidence). Based on 353 per 1000 participants reporting low levels of distress, this corresponds to 191 more men (92 more to 311 more) per 1000 reporting low levels of distress with SSRIs.  SSRI treatment probably increases adverse events compared to placebo (RR 1.71, 95% CI 1.48 to 1.99; moderate-certainty evidence). Based on 243 adverse events per 1000 among men receiving placebo, this corresponds to 173 more (117 more to 241 more) men having an adverse event with SSRIs.  SSRI treatment may increase IELT compared to placebo (mean difference (MD) 3.09 minutes longer, 95% CI 1.94 longer to 4.25 longer; low-certainty evidence).

AUTHORS' CONCLUSIONS

SSRI treatment for PE appears to substantially improve a number of outcomes of direct patient importance such as symptom improvement, satisfaction with intercourse and perceived control over ejaculation when compared to placebo. Undesirable effects are a small increase in treatment withdrawals due to adverse events as well as substantially increased adverse event rates. Issues affecting the certainty of evidence of outcomes were study limitations and imprecision.

Pharmacokinetics and Safety of Dapoxetine Hydrochloride in Healthy Chinese Men: Impact of Dose and High-Fat Meal

Dapoxetine is the first oral medication specifically developed for the on-demand treatment of premature ejaculation. The pharmacokinetics and safety of 30 mg (n = 40) and 60 mg (n = 38) dapoxetine in healthy Chinese under fasted and fed states were assessed in 2 studies. Both studies are random, single-center, 2-period, open-label, 2-way crossover designs. Plasma concentration of dapoxetine was determined by high-performance liquid chromatography-tandem mass spectrometry, and the pharmacokinetic parameters were calculated using noncompartmental analysis. Dapoxetine was quickly absorbed and reached maximum concentration 1 to 3 hours after oral administration. Elimination was biphasic, and the plasma concentration decreased to 3% to 7% of maximum concentration by 24 hours while half-life was 15 to 18 hours. Meantime, high-fat meals slightly increased its exposure. Both doses of dapoxetine were well tolerated. The adverse events in the high-dose group under fasted and fed states were 37.9% and 19.0%, respectively.

Safety and Effectiveness of Dapoxetine On Demand in Chinese Men With Premature Ejaculation: Results of a Multicenter, Prospective, Open-Label Phase IV Study

INTRODUCTION

Dapoxetine on demand has been approved for premature ejaculation (PE) management in China; however, studies on the efficacy and safety of this treatment in the Chinese population are scarce.

AIM

The aim of this study was to evaluate the safety and effectiveness of dapoxetine 30 mg and 60 mg on demand in Chinese men with PE.

METHODS

Phase IV real-world study on 1,252 patients with PE. If men reported no response to dapoxetine 30 mg after 4 weeks treatment, dapoxetine has been uptitrated at 60 mg for 4 weeks more.

MAIN OUTCOME MEASURE

Self-reported data were collected for demographics, general and sexual health characteristics, PE severity, and treatment safety and effectiveness, as measured by the PE profile questionnaire.

RESULTS

Adverse events (AEs), such as nausea, thirst, headache, and dizziness, similarly to previous literature, were detected. The treatment-emergent AEs rate was higher in the patients treated with 30 and 60 mg (n = 192) compared with those treated with the dapoxetine 30 mg only (n = 1060) (34.4% vs 15.8%, respectively). No new safety concerns were observed. The overall effectiveness rates were 88.2% in subjects using 30 mg of dapoxetine, whereas a rescue from the previous failure was in 55.7% in the patients who received 60 mg after the initial 30 mg. Overall, 83.2% responded to dapoxetine at dosages equal to or lower than 60 mg.

CONCLUSION

The results in this study demonstrated in a large Chinese population that on-demand dapoxetine is a safe and effective symptomatic treatment in patients with PE. J Peng, L Yang, L Liu, et al. Safety and Effectiveness of Dapoxetine On Demand in Chinese Men With Premature Ejaculation: Results of a Multicenter, Prospective, Open-Label Phase IV Study. Sex Med 2021;9:100296.

High performance liquid chromatography - Mass spectrometric bioanalytical method for the determination of dapoxetine in human plasma: Application for bioequivalence study

Dapoxetine is an oral medication used for treatment of premature ejaculation (PE) in men aged (18-64 years). In this study, we present a validated, precise and sensitive method for determination of dapoxetine in human plasma by liquid chromatography/ electrospray ionization-tandem mass spectrometry. Dapoxetine and the internal standard (Dapoxetine- d₆) were extracted from plasma via liquid-liquid extraction (LLE). The LC separation was performed utilizing ACE C8 (4.6 X50) mm, 5 µm column. The mobile phase was composed of acetonitrile and buffer (0.01 M Ammonium acetate +0.02% Formic acid solution) (85:15, v/v). The method was linear within the concentration range of 5.0-600 ng/mL for Dapoxetine in human plasma. Short analytical run was achieved with 1.6 min run time. Intra-day and inter-day accuracy was between 97 and 106% with precision (CV, %) of ≤ 5% achieved across all the quality control samples. Dapoxetine was stable in several conditions with recovery rates > 90%. This method was utilized successfully in clinical pharmacokinetic study following oral administration of 60 mg Dapoxetine tablets in 36 healthy male subjects. The result for all 90% confidence intervals were within the preset ranges. The method proved to be highly reproducible and sensitive and thus can be employed in bioequivalence studies and large scale sample analysis of Dapoxetine.

Trends in reported male sexual dysfunction over the past decade: an evolving landscape

We investigated changes in patterns of reported male SDs at a single academic centre over a 10-year time frame. Comprehensive data of 2013 patients consecutively assessed for the first time by a single Sexual Medicine expert between 2006 and 2019 has been analysed. All patients were assessed with a thorough sexual and medical history. Primary reason for seeking medical help at first assessment was recorded for all patients and categorized as: erectile dysfunction (ED), premature ejaculation (PE), low/reduced sexual desire/interest (LSD/I), Peyronie's disease (PD), and other SDs. Linear and logistic regression models tested the association between different reasons for seeking medical help and the time at first evaluation. Local polynomial regression model explored the probability of reporting different SDs over the analysed time frame. Median (IQR) age at first clinical assessment was 50 (38-61) years. Overall, most patients were assessed for ED (824; 41%), followed by PD (369; 18%), PE (322; 16%), LSD/I (204; 10%) and other SDs (294; 15%). Significant changes in terms of reported SD over the analysed time frame were observed. The likelihood of assessing patients for ED significantly increased up to 2013, with a decrease in the past 5 years (p < 0.001). PE assessment at presentation linearly decreased over time (OR: 0.94; 95% CI: 0.91-0.96; p < 0.001). Patients assessed during the past few years were more likely to report PD (OR: 1.20; 95% CI: 1.15-1.25; p < 0.001) and LSD/I (OR: 1.21; 95% CI: 1.16-1.26; p < 0.001), with a linear increase over the evaluated time frame. Likewise, patients were also more likely to report other SDs (Coeff: 1.06; 95% CI: 1.02-1.10; p = 0.004), with a linear increase over time. These results may reflect real changes in SD incidence, increased public awareness towards different SDs and the possible impact of novel treatments available on the market throughout the same time frame.

Phosphodiesterase-5 Inhibitors for Premature Ejaculation: Systematic Review and Meta-Analysis of Placebo-Controlled Trials

The purpose of this analysis is to assess the efficacy and safety of phosphodiesterase-5 inhibitors (PDE5Is) for the treatment of premature ejaculation (PE). A comprehensive search was performed to ascertain from trials about PDE5Is for the treatment of PE and compare the results, including intravaginal ejaculatory latency time (IVELT), score of sexual satisfaction scale, and side effects, between the group treated with PDE5Is and that treated with placebo. Seven studies involving a total of 471 patients were included in this meta-analysis. This analysis showed that patients who were treated with PDE5Is had significantly increased IVELT (mean difference [MD] 2.60; 95% CI [1.85, 3.36]; p < .00001) and score of sexual satisfaction scale (MD 2.04; 95% CI [0.78, 3.30]; p = .002) compared with the group on placebo. More patients had side effects while taking PDE5Is, such as headache, dizziness, flushing, and nasal congestion. PDE5Is were significantly more effective than placebo in the treatment of PE. Side effects were more common among patients who were treated with PDE5Is.

Two-Step Optimization to Develop a Transdermal Film Loaded With Dapoxetine Nanoparticles: A Promising Technique to Improve Drug Skin Permeation

Dapoxetine (DPX) is an orally administered drug for the treatment of premature ejaculation (PE). One of the challenges of administering DPX orally as a tablet is its poor bioavailability (ie, 42%) due to extensive first-pass metabolism. Thus, it is vital to develop a new formulation and mode of delivery to achieve the unmet needs of PE treatment. In this study, an optimized DPX polymeric nanoparticle (PNP) was developed and subsequently loaded into a transdermal film. The Box–Behnken design was utilized to optimize 3 formulation factors affecting the particle size and entrapment efficiency (EE) of chitosan (CS)-alginate (ALG) PNPs. A 3-level factorial design was used to study the effect of 2 variables affecting DPX cumulative percent released and percent elongation from transdermal films loaded with DPX-PNPs. Permeation parameters were calculated following ex vivo permeation study through rat skin. Transport of the PNPs across the skin layers was investigated using a fluorescence laser microscope. Results revealed that an optimized PNPs formulation was developed with a particle size 415.94 nm and EE 37.31%. Dapoxetine was successfully entrapped in the polymeric matrix. Chitosan and ALG interacted electrostatically with the studied cross-linking agents to form a polyelectrolyte complex. The ex vivo study illustrated a sustained release profile of DPX with enhanced skin permeation from the film loaded PNPs. Moreover, the PNPs was able to penetrate deeper into skin layers. Therefore, DPX transdermal film developed in this work could be considered as a successful drug delivery with better patient compliance for the treatment of PE.

Enhanced pharmacokinetic performance of dapoxetine hydrochloride via the formulation of instantly-dissolving buccal films with acidic pH modifier and hydrophilic cyclodextrin: Factorial analysis, in vitro and in vivo assessment

Instantly dissolving buccal films have gained attention owing to their easy administration and capability to surmount the hepatic first pass effect of drugs. Dapoxetine hydrochloride (DPX) has a low oral bioavailability due to significant hepatic first pass metabolism. In addition, DPX is a weakly basic drug with a pH dependent solubility that could limit its dissolution in the body neutral fluids. In order to surpass these challenges, this work aimed at enhancing DPX bioavailability via the formulation of instantly dissolving buccal films comprising a pH modifier and a hydrophilic cyclodextrin. Tartaric acid and hydroxypropyl beta-cyclodextrin were selected as dual solubilizing agents based on the screening study. 3² factorial design was employed for the formulation and optimization of DPX films. Statistical analysis revealed that hydroxypropyl methyl cellulose E5: maltodextrin ratio and propylene glycol concentrations have significant effects on mechanical properties, percent DPX dissolved after 5 min, and in vivo mouth dissolving time at P  < 0.05. The optimized film [HPMC E5: MDX, 1:1 and 1% PG] showed no significant change of properties or drug dissolution upon storage at 40 °C/75% RH for a period of 3 months. In addition, the optimized film showed significantly enhanced absorption relative to the oral reference tablet. Therefore, the optimized film could be considered a promising delivery system for DPX with expected improved patient compliance and enhanced pharmacokinetic performance.

Efficacy of dapoxetine treatment in Chinese patients with premature ejaculation and possible factors affecting efficacy in the real-world practice

BACKGROUND

The treatment effect of dapoxetine in real-world practice is not well established. This study was to investigate the factors influencing efficacy of dapoxetine for the treatment of Premature ejaculation (PE) in the real-world setting.

METHODS

Altogether 154 patients were followed up between Jan 2015 and Dec 2015. The clinical global impression of change (CGIC), premature ejaculation profile (PEP), the estimated intravaginal ejaculation latency time (eIELT) and estimated number of intravaginal thrusts before ejaculation (NITBE) were collected. The clinical characteristics of patients with CGIC = 0 and CGIC≥1 were compared.

RESULTS

After 4 weeks treatment, an obvious improvement compared with the baseline was found regarding mean eIELT (2.4 ± 1.6 min vs 1.0 ± 0.7 min, P < 0.001) and mean NITBE (85.9 ± 61.9 times vs 37.4 ± 28.6 times, P < 0.001). The proportion of patients with a self-evaluation of at least "slightly better" and were categorized into "CGIC≥1" group was 70.1%. There were significant differences between patients in the "CGIC = 0" and "CGIC≥1" groups regarding mean NITBE (P = 0.010) and PEDT (P = 0.009) score at baseline. The adverse effects were acceptable.

CONCLUSION

Dapoxetine was well-tolerated and improved the sexual satisfaction of patients with PE. The severity of PE based on PEDT and NITBE suggest that there could be an effectiveness change with dapoxetine use in real-world practice.

Premature Ejaculation: Aetiology and Treatment Strategies

Premature ejaculation (PE) is a highly prevalent male sexual dysfunction that is often neglected, presenting a currently unmet therapeutic need. The classification of PE has historically been varied and at times ambiguous, contributing to inaccurate prevalence estimates. This review uses the International Society for Sexual Medicine (ISSM) definition of PE, which includes reduced ejaculatory latency, lack of control and associated negative personal consequences. Patient assessment and management options differ depending on the classification of PE and it is the role of the clinician to appropriately classify patients and be aware of the correct management strategies. This review provides an overall background of PE in terms of classification and underlying physiology, patient assessment and management strategies along with the scientific rationale for treatment. Patients with lifelong and acquired PE are most likely to benefit from combination therapy of pharmacological treatment in the form of selective serotonin re-uptake inhibitor dapoxetine, psychosexual behavioural therapy and psychological therapy.

Pelvic muscle floor rehabilitation as a therapeutic option in lifelong premature ejaculation: long-term outcomes

The aim of the study was to evaluate the long-term outcomes of pelvic floor muscle (PFM) rehabilitation in males with lifelong premature ejaculation (PE), using intravaginal ejaculatory latency time (IELT) and the self-report Premature Ejaculation Diagnostic Tool (PEDT) as primary outcomes. A total of 154 participants were retrospectively reviewed in this study, with 122 completing the training protocol. At baseline, all participants had an IELT ≤60 s and PEDT score >11. Participants completed a 12-week program of PFM rehabilitation, including physio-kinesiotherapy treatment, electrostimulation, and biofeedback, with three sessions per week, with 20 min for each component completed at each session. The effectiveness of intervention was evaluated by comparing the change in the geometric mean of IELT and PEDT values, from baseline, at 3, 6, and 12 months during the intervention, and at 24 and 36 months postintervention, using a paired sample 2-tailed t-test, including the associated 95% confidence intervals. Of the 122 participants who completed PFM rehabilitation, 111 gained control of their ejaculation reflex, with a mean IELT of 161.6 s and PEDT score of 2.3 at the 12-week endpoint of the intervention, representing an increase from baseline of 40.4 s and 17.0 scores, respectively, for IELT and PEDT (P < 0.0001). Of the 95 participants who completed the 36-month follow-up, 64% and 56% maintained satisfactory ejaculation control at 24 and 36 months postintervention, respectively.

Transcutaneous electric nerve stimulation to treat patients with premature ejaculation: phase II clinical trial

A phase II single-arm trial was conducted from June 2017 to October 2018 to evaluate the efficacy and safety of transcutaneous posterior tibial nerve stimulation (TPTNS) for premature ejaculation (PE) treatment. Twelve men with PE and no prior treatment were enrolled, one was withdrawn and 11 subjects provided data for the main outcome. TPTNS consisted of 30-min sessions of the application of 20 Hz with a pulse amplitude of 200 µsec. The intensity was adjusted based on individual sensibility. The participants received 3 weekly sessions for 12 consecutive weeks. Follow-up continued for 9 months after therapy completion. The main outcome was a threefold increase in the intravaginal ejaculation latency time (IELT) at week 12. Eleven patients completed therapy, and 54.5% (p = 0.037) showed tripled baseline IELT scores at week 12. The IELT increased 4.8-fold, 6.8-fold, and 5.4-fold at weeks 12, 24, and 48, respectively. One episode of constipation was reported, and one patient reported a sensation of heat in the leg during one therapy session. The findings suggest that TPTNS therapy delays ejaculation in patients with lifelong premature ejaculation, with no serious secondary effects. Controlled trials with larger sample sizes are needed to verify these results.

Modeling Human Sexual Motivation in Rodents: Some Caveats

Sexual behavior is activated by motivation. An overwhelming majority of experimental studies of the intricacies of sexual motivation has been performed in rodents, most of them in rats. Sometimes it is desirable to generalize results obtained in this species to other species, particularly the human. It is hoped that studies of the neurobiology of rodent sexual behavior may shed light on the central nervous mechanisms operating in the human, and the search for efficient pharmacological treatments of human sexual dysfunctions relies partly on studies performed in rodents. Then the issue of generalizability of the rodent data to the human becomes crucial. We emphasize the importance of distinguishing between copulatory acts, behavior involving the genitals, and the preceding event, the establishment of physical contact with a potential mate. Comparisons between the structure of copulatory behavior in rats and humans show abysmal differences, but there may be some similarity in the underlying mechanisms. The endocrine control of sex behavior is shortly mentioned, and we also compare the effects of the few drugs known to affect both rodent and human copulatory behavior. The stimuli activating sexual motivation, often called desire in the human literature, are examined, and the sexual approach behaviors in rats and humans are compared. There is a striking similarity between these species in how these behaviors respond to drugs. It is then shown that the intensity of sexual approach is unrelated to the intensity of copulatory behavior. Even though the approach is a requisite for copulation, an activity that requires at least two individuals in close physical contact, these two aspects of sexuality do not covary. This is similar to the role of the testosterone in men and male rats: although the hormone is needed for sex behavior, there is no correlation between serum testosterone concentration and the intensity of copulation. It is also pointed out that human sexual behavior is mostly determined by social conventions, whereas this is not the case in rats and other rodents. It is concluded that some observations in rats can be generalized to the human, but extreme caution must be exercised.

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.

Effect of premature ejaculation desensitisation therapy combined with dapoxetine hydrochloride on the treatment of primary premature ejaculation

To evaluate the overall treatment benefits of premature ejaculation desensitisation therapy combined with 30 mg dapoxetine hydrochloride treatment on patients with primary premature ejaculation (PPE). Ninety-nine PPE patients were randomly divided into two groups at the ratio of 2:1. Sixty-six PPE patients received premature ejaculation desensitisation therapy accomplished by Weili Automatic Semen Collection-Penis Erection Detection and Analysis workstation (WLJY-2008) combined with 30 mg dapoxetine hydrochloride treatment (DTCD group), and another 33 patients received 30 mg dapoxetine hydrochloride-only treatment (DO group). Intravaginal ejaculation latency time (IELT) and premature ejaculation profile (PEP) were recorded before and during the treatment, and clinical global impression of change (CGIC) in PPE was recorded at the fourth week and the end of the treatment and the items. In both groups were significantly improved (p < 0.0001) in IELT, PEP and CGIC for premature ejaculation compared with baseline, and DTCD treatment showed a more significant improvement on PPE patients in the items compared with DO treatment (p < 0.05). Thus, premature ejaculation desensitisation combined with dapoxetine therapy may be a better choice for improving premature ejaculation with PPE.

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.

Phase I and phase II clinical trials for the treatment of male sexual dysfunction-a systematic review of the literature

INTRODUCTION

The prevalence of sexual dysfunctions has increased over the last decades; despite a number of available treatments for erectile dysfunction (ED), premature ejaculation (PE), and Peyronie's disease (PD), still several unmet therapeutic needs deserve to be fulfilled. The aim of this review is to detail on phase I and II clinical trials investigating novel medical treatments for ED, PE, and PD.

AREAS COVERED

We conducted a systematic review of the literature including both published and ongoing phase I and II registered trials focused on medical treatment of ED, PE, and PD during the last 5 years. A total of 35 trials have been identified. Most studies (63%) investigated ED treatments and 26% were still ongoing. Stem cells (SCs) therapy was assessed in 28% of trials.

EXPERT OPINION

SCs therapy represent a promising treatment for ED although only few patients have been treated to date. Likewise, the oral selective oxytocin receptor antagonists for treating PE showed excellent safety profile and deserve further investigations in phase III trials. Preliminary results of novel topical treatments for PD with fibrinolytic and antiinflammatory drugs are encouraging, but urgently need to be confirmed in large placebo-controlled trials.

Comparison of the clinical efficacy and safety of the on-demand use of paroxetine, dapoxetine, sildenafil and combined dapoxetine with sildenafil in treatment of patients with premature ejaculation: A randomised placebo-controlled clinical trial

The aim of the study was to compare the clinical efficacy and safety of the on-demand use of paroxetine, dapoxetine, sildenafil and combined dapoxetine with sildenafil in treatment of patients with premature ejaculation (PE). In a single-blind placebo-controlled clinical study, 150 PE patients without erectile dysfunction (ED) were included during the period of March 2015 to May 2016. Patients were randomly divided into five groups (30 patients each). On demand placebo, paroxetine (30 mg), dapoxetine (30 mg), sildenafil citrate (50 mg) and combined dapoxetine (30 mg) with sildenafil citrate (50 mg) were given for patients for 6 weeks in each group respectively. All patients were instructed to record intravaginal ejaculatory latency time (IELT) and evaluated with Premature Ejaculation Diagnostic Tool (PEDT) and the patient satisfaction score before and after treatment. The mean of IELT, satisfaction score and PEDT in all groups was significantly improved after treatment (p value = .001). Combined dapoxetine with sildenafil group had the best values of IELT, satisfaction scores and PEDT in comparison with other treatment groups (p value <.001). The combined dapoxetine with sildenafil therapy could significantly improve PE patients without ED as compared to paroxetine alone or dapoxetine alone or sildenafil alone with tolerated adverse effects.