Efficacy and safety of dapoxetine for premature ejaculation: an updated systematic review and meta-analysis

Effects of CYP2D6 *10 and *41 Variants in Healthy Chinese Men on the Pharmacokinetics of Dapoxetine

Dapoxetine is a selective serotonin reuptake inhibitor (SSRI) used to treat premature ejaculation (PE), and is mainly metabolized by CYP2D6, CYP3A4, and flavin-containing monooxygenase 1. The purpose of the study was to evaluate the effect of CYP2D6 polymorphism on the pharmacokinetics of dapoxetine in healthy Chinese men. Thirty-nine subjects who received a single oral dose of 30 mg dapoxetine hydrochloride were classified based on their CYP2D6 genotype: *1/*1 (n = 9), *1/*41 (n = 1), *1/*10 (n = 12), *10/*41 (n = 3), or *10/*10 (n = 14). The difference in pharmacokinetic parameters between different genotype groups was analyzed and then scored according to the activity score system. Compared with the wild-type subjects of CYP2D6 *1/*1, the peak plasma concentration (Cmax) and the area under the plasma drug concentration-time curve (AUCinf) of dapoxetine in the *10/*10 and *10/*41 groups were notably increased (P ≤ .05). Significant differences in Cmax, AUC, volume of distribution/bioavailability (V/F) and clearance/bioavailability (CL/F) were observed among dapoxetine activity score groups (P ≤ .05). The AUCinf was increased significantly (154% and 89.73%, P ≤ .05) and the Cmax was increased significantly (73.45% and 42.67%, P ≤ .05) in CYP2D6 *10/*41 subjects, compared with CYP2D6 *1/*1 and *1/*10 subjects. The results obtained indicated that CYP2D6 *10 and *41 polymorphisms have significant effects on the pharmacokinetic properties of dapoxetine.

Progressive arousal: a new concept and definition for premature ejaculation

Background

Premature ejaculation (PE) is a nosologic entity with issues in its conceptualization and definition.

Aim

To understand if the altered sexual response in men with PE is in the orgasm phase, as currently assumed, or the arousal phase with difficulties in modulating, regulating, or decreasing sexual arousal.

Methods

Men were recruited who looked for help for PE and met the diagnostic criteria according to clinical standards. The participants completed a sociodemographic survey and the Premature Ejaculation Diagnostic Tool. They also performed a masturbation exercise with a maximum of 5 stops, with the intention of prolonging the arousal phase. The time of the exercise was measured from the beginning of genital masturbation to ejaculation.

Outcomes

We calculated the total time of the exercise, the median time at each start, and the number of dropouts. We performed a pairwise comparison analysis between starts and made a survival curve representing the percentage of men who remained in the exercise.

Results

A total of 481 men with PE participated (mean ± SD; age, 29.25 ± 8.72 years). We found that the expected median survival time until ejaculation was 317.00 seconds (95% CI, 288.34-345.65). However, the average time during stimulation decreased as the exercise progressed, and statistically significant differences were observed in their pairwise comparison (P < .001). Also, the chances of ejaculation increased as the exercise progressed, with 62.16% of the participants ejaculating before the end of the exercise. The results indicated increasing sexual arousal, where stops in stimulation were progressively less effective at maintaining ejaculation times at starts.

Clinical Implications

We showed that the arousal phase is altered in PE, not the orgasm phase, and this could finally have implications in the diagnosis and/or treatment of this condition.

Strengths and Limitations

The analysis of the times at starts and stops in a masturbation exercise in men with PE, had been barely addressed before. In the future, it would be important to verify the effect of stops during sexual intercourse and to incorporate a control group of men without PE.

Conclusions

We propose a new conceptualization and definition for PE: progressive arousal disorder is the inability to modulate, regulate, or decrease arousal during any sexual activity, even with brief stops during sexual stimulation, causing unwanted ejaculation.

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.

Management of premature ejaculation: a clinical guideline from the Italian Society of Andrology and Sexual Medicine (SIAMS)

Premature ejaculation (PE) is the most prevalent male sexual dysfunction, and the most recently defined. PE is often mistakenly considered a purely psychosexological symptom by patients: the lacking awareness in regards to the pathophysiology and treatments often lead to resignation from the patients' side, making PE the most underdiagnosed sexual complaint. However, an ever-growing body of evidence supporting several organic factors has been developed in the last decades and several definitions have been suggested to encompass all defining features of PE. In the present document by the Italian Society of Andrology and Sexual Medicine (SIAMS), we propose 33 recommendations concerning the definition, pathophysiology, treatment and management of PE aimed to improve patient care. These evidence-based clinical guidelines provide the necessary up-to-date guidance in the context of PE secondary to organic and psychosexological conditions, such as prostate inflammation, endocrine disorders, and other sexual dysfunctions, and suggest how to associate pharmacotherapies and cognitive-behavioral therapy in a couple-centered approach. New therapeutic options, as well as combination and off-label treatments, are also described.

Redefining a sexual medicine paradigm: subclinical premature ejaculation as a new taxonomic entity

Premature ejaculation (PE) and poor ejaculatory control are multidimensional sexual symptoms estimated to affect almost one-third of men, severely impairing the overall quality of life of patients and their partners. However, patients who do not completely fulfil the definition criteria for PE rarely receive a diagnosis or adequate treatment, with the risk of subsequent progression from initial, subclinical symptoms to clinically overt PE, frequently with other sexual comorbidities. Thus, the current definitions of PE warrant review, in order to consider and propose a new taxonomy encompassing other unaddressed, crucial clinical aspects of PE. These newly proposed criteria include the recommendation for a primary screening for erectile dysfunction (ED), as PE and ED can be comorbid in up to 50% of patients but have never before been considered as a unified clinical entity. In order to facilitate clinical practice and improve clinical management of men with PE and comorbid conditions, we propose and define the new taxonomic clinical entities of subclinical PE (SPE) and loss of control of erection and ejaculation (LCEE). Application of these diagnoses to men who meet the criteria for SPE and/or LCEE, but not the overt conditions, could improve access to treatment for these patients and reduce progression to the more serious clinical disorder.