Fluoxetine and premature ejaculation: a double-blind, crossover, placebo-controlled study

Current and emerging treatment options for premature ejaculation

Premature ejaculation (PE) is a prevalent male sexual dysfunction. Current standard treatment regimens include behavioural therapies, topical anaesthetics, dapoxetine and other selective serotonin reuptake inhibitors (SSRIs). Most of the pharmacotherapeutic options target neurotransmitters (such as serotonin and oxytocin) that have a role in the ejaculation mechanism. However, these treatments are mildly effective and only provide a temporary delay in the ejaculation latency time, and PE recurs when the treatment is stopped. Thus, a treatment for PE is urgently needed and research is ongoing to find the ideal PE therapy. The efficacy and safety of topical anaesthetics and SSRIs in delaying ejaculation have been confirmed in many well-designed controlled trials. Both preclinical and clinical studies on new-generation SSRIs are ongoing. Moreover, promising results came from clinical trials in which the efficacy of on-demand PE therapies targeting neurotransmitters other than serotonin, such as α1-adrenoceptor antagonists and oxytocin antagonists, was assessed. Surgical intervention and neuromodulation have been proposed as potential treatment options for PE; however, current PE guidelines do not recommend these treatments owing to safety concerns.

Off-label Uses of Selective Serotonin Reuptake Inhibitors (SSRIs)

Psychiatric drugs have primacy for off-label prescribing. Among those, selective serotonin reuptake inhibitors (SSRIs) are highly versatile and, therefore, widely prescribed. Moreover, they are commonly considered as having a better safety profile compared to other antidepressants. Thus, when it comes to off-label prescribing, SSRIs rank among the top positions. In this review, we present the state of the art of off-label applications of selective serotonin reuptake inhibitors, ranging from migraine prophylaxis to SARS-CoV-2 antiviral properties. Research on SSRIs provided significant evidence in the treatment of premature ejaculation, both with the on-label dapoxetine 30 mg and the off-label paroxetine 20 mg. However, other than a serotoninergic syndrome, serious conditions like increased bleeding rates, hyponatremia, hepatoxicity, and post-SSRIs sexual dysfunctions, are consistently more prominent when using such compounds. These insidious side effects might be frequently underestimated during common clinical practice, especially by nonpsychiatrists. Thus, some points must be addressed when using SSRIs. Among these, a psychiatric evaluation before every administration that falls outside the regulatory agencies-approved guidelines has to be considered mandatory. For these reasons, we aim with the present article to identify the risks of inappropriate uses and to advocate the need to actively boost research encouraging future clinical trials on this topic.

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.

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.

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.

Sexual dysfunction in patients with spinal cord lesions

Many aspects of sexuality can be disrupted following a spinal cord lesion (SCL). It can alter an individual's self-esteem and body image, interfere with positioning and mobility, introduce unexpected problems with incontinence and spasticity, decrease pleasure, and delay orgasm. Sexual concerns in men can involve erectile function, essential for intercourse, ejaculation function, necessary for fertility, and the ability to reach orgasm. In women they can involve concerns with vaginal lubrication, genital congestion, and vaginal infections, which can all go unnoticed, and orgasm, which may be lost. All of these concerns must be addressed during rehabilitation as individuals with SCL continue to live an active sexual life, and consider sexuality among their top priority for quality of life. This chapter describes the impact of SCL on various phases of men's and women's sexual responses and on various aspects of sexuality. Treatments are described in terms of what is currently available and what is specific to the SCL population. New approaches in particular for women are described, along with tips from sexual counseling which consider an overall approach, taking into account the primary, secondary, and tertiary consequences of the SCL on the individual's sexuality. Throughout the chapter, attempts are made to integrate neurophysiologic knowledge, findings from the literature on SCL, and clinical experience in sexual rehabilitation.

Disorders of orgasm and ejaculation in men

INTRODUCTION

Ejaculatory/orgasmic disorders are common male sexual dysfunctions, and include premature ejaculation (PE), inhibited ejaculation, anejaculation, retrograde ejaculation, and anorgasmia.

AIM

To provide recommendations and guidelines concerning current state-of-the-art knowledge for management of ejaculation/orgasmic disorders in men.

METHODS

An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 25 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge of disorders of orgasm and ejaculation represent the opinion of seven experts from seven countries developed in a process over a 2-year period.

MAIN OUTCOME MEASURE

Expert opinion was based on grading of evidence-based medical literature, widespread internal committee discussion, public presentation and debate.

RESULTS

Premature ejaculation management is largely dependent upon etiology. Lifelong PE is best managed with PE pharmacotherapy (selective serotonin re-uptake inhibitor [SSRI] and/or topical anesthetics). The management of acquired PE is etiology specific and may include erectile dysfunction (ED) pharmacotherapy in men with comorbid ED. Behavioral therapy is indicated when psychogenic or relationship factors are present and is often best combined with PE pharmacotherapy in an integrated treatment program. Retrograde ejaculation is managed by education, patient reassurance, pharmacotherapy, or bladder neck reconstruction. Delayed ejaculation, anejaculation, and/or anorgasmia may have a biogenic and/or psychogenic atiology. Men with age-related penile hypoanesthesia should be educated, reassured, and instructed in revised sexual techniques which maximize arousal.

CONCLUSIONS

Additional research is required to further the understanding of the disorders of ejaculation and orgasm.

Sexual dysfunction and related risk factors in a cohort of middle-aged Ecuadorian women

Sexuality is a complex phenomena that can be affected by psychological and physiological influences, among them the climacteric. The present study aimed to assess the incidence of sexual dysfunction and related risk factors in a cohort of low socioeconomic middle-aged Ecuadorian women. For this, 385 healthy sexually active women between 40 and 65 years old accompanying patients being attended at the Enrique C. Sotomayor Obstetrics and Gynecology Hospital of Guayaquil, Ecuador were asked to take part in the study. Subjects were surveyed using DSM IV criteria to assess sexual dysfunctions and record coital frequency over the past 12 months. Mean age of the sample was 47 +/- 5.6 years (median: 46), 43.1% were postmenopausal and a 17.9% of them were on hormone therapy (HT). A total of 53.5% maintained at least four sexual intercourses per month. Masculine erectile dysfunction and premature ejaculation was present in 21.3% and 59.2%, respectively. Female sexual dysfunction was present in a 78.4% of women included in the study. Desire dysfunction was the most frequent disorder (62.6%). The incidence of sexual dysfunction increased from 71.6% in the 40 - 44 year group, to 92.3% in the 60 - 64 year group (p < 0.05). The risk of sexual dysfunction was increased 7.6-fold when male erectile dysfunction was present (CI: 1.7 - 33.8), 5.8 in cases of premature ejaculation (CI: 2.9 - 11.3), 2.9 by marital status (married) (CI: 1.5 - 5.7) and 4.1 by antidepressant therapies (CI: 1 - 15.7), whereas schooling > or =12 years, having only one sexual partner and > or =4 intercourses per month were factors that decreased sexual dysfunction risk. In conclusion, the incidence of sexual dysfunction in this low socioeconomic Ecuadorian women cohort was higher than expected. Male sexual dysfunctions, marital status and antidepressant use were the most important predicting risk factors.

Premature Ejaculation

Premature ejaculation (PE) is a frequent male sexual complaint that is mediated mainly by disturbances of serotonergic neurotransmission and certain serotonin (5-HT) receptors and, to a lesser extent, oxytocinergic neurotransmission in the CNS. The current Diagnostic Manual of Mental Disorders (fourth edition, revised text) [DSM-IV-TR] definition of PE has a low positive predictive value and is inadequate for clinical, epidemiological and drug treatment research. Categorisation of PE into four well defined syndromes has recently been proposed for the pending DSM (fifth edition) definition of PE. Over the last decade, an increasing number of studies of drug treatment of PE have been published. A meta-analysis of those studies, conducted in accordance with current standards of evidence-based medicine, demonstrated similar efficacies for daily treatment with the serotonergic antidepressants paroxetine hemihydrate, clomipramine, sertraline and fluoxetine, with paroxetine (hydrochloride) hemihydrate exerting the strongest effect on ejaculation. On the basis of fundamental insights into serotonergic neurotransmission, it has been suggested that on-demand selective serotonin reuptake inhibitor (SSRI) treatment will not lead to similarly impressive delays in ejaculation as has been observed with daily SSRI treatment. Indeed, some on-demand studies with SSRIs and studies with the new SSRI dapoxetine have shown a weak ejaculation-delaying effect after 1-2 hours of drug intake. Apart from daily treatment with SSRIs, PE can be delayed by on-demand use of topical anaesthetics and tramadol. Treatment with phosphodiesterase type 5 inhibitors should not be prescribed to men with PE with normal erectile function, but may be used if PE is accompanied by erectile difficulties. There is no scientific support for treatment of PE with intracavernous injection of vasoactive drugs. Animal studies have shown that strong immediate ejaculation delay may be induced by administration of a combination of an SSRI with a serotonin 5-HT(1A) receptor antagonist. The combination of an SSRI and any other compound that immediately and potently raises serotonin neurotransmission and/or use of oxytocin receptor antagonists may form the basis for the development of new on-demand and/or daily drugs for the treatment of PE.

Serotonin and Premature Ejaculation: From Physiology to Patient Management

INTRODUCTION

Premature ejaculation (PE), whose pathophysiology is still not clearly identified, is the most common male sexual dysfunction, yet it remains underdiagnosed and undertreated. The aims of this paper are to provide a scientific and pharmacologic rationale, and to discuss to what extent selective serotonin reuptake inhibitors (SSRIs) can help patients with PE.

MATERIALS AND METHODS

A comprehensive evaluation of available published data included analysis of published full-length papers that were identified with Medline and Cancerlit from January 1981 to January 2006. Official proceedings of internationally known scientific societies held in the same time period were also assessed.

RESULTS

The central ejaculatory neural circuit comprises spinal and cerebral areas that form a highly interconnected network. The sympathetic, parasympathetic, and somatic spinal centers, under the influence of sensory genital and cerebral stimuli integrated and processed at the spinal cord level, act in synergy to command physiologic events occurring during ejaculation. Experimental evidence indicates that serotonin (5-HT), throughout brain descending pathways, exerts an inhibitory role on ejaculation. To date, three 5-HT receptor subtypes (5-HT1A, 5-HT1B, and 5-HT2C) have been postulated to mediate 5-HT's modulating activity on ejaculation. Pharmacologic manipulation of the serotonergic system has been performed in rats, with the antidepressant selective serotonin reuptake inhibitors (SSRIs) exhibiting the greatest efficacy in delaying ejaculation. The mechanism of action by which SSRIs modulate central 5-HT tone has been studied in depth, but gaps in this knowledge prevent an explanation of the efficacy of acute treatment in delaying ejaculation. Emerging clinical evidence indicates chronic and on-demand dosing of SSRIs has a beneficial effect for the treatment of men with PE, at least for paroxetine. On-demand dapoxetine, and SSRI with a short half-life, recently has been shown to significantly increase intravaginal latency time and PE patient-related outcomes in phase 3 clinical trials.

CONCLUSIONS

Nowadays there is no doubt that PE can be treated effectively by SSRIs. Nevertheless their mechanism of action is not yet well understood and deserves more research. In particular it is not understood why all the SSRIs are not equal in terms of their ability to delay ejaculation. Therefore, there is a need for more research to better characterize the mechanism of action of SSRIs as well their clinical benefit in patients affected by PE.

Management of the cardinal features of andropause

There are several problems facing aging men, especially sexual dysfunction, hypogonadism, and psychologic changes. This constellation of changes is sometimes referred to as "manopause" or "andropause." Unlike the dramatic changes in the hormonal milieu occurring during menopause in women, the age-related changes in reproductive hormones of men are subtle and occur gradually throughout the years of mature life. It has been estimated that circulating testosterone (T) declines longitudinally from age 19 at an average rate of 1% per year. The free or dialyzable fraction of serum T and the bioavailable (the sum of free fraction and loosely bound to albumin fraction) T decline more rapidly with age. Although the essential role of androgens in reproductive tissue development and emergence of secondary sex characteristics is well known, their role in adult sexual function seems to be primarily facultative. The effect of T on the central nervous system extends beyond sexual behavior. T has been shown to alter mood, memory, ability to concentrate, and the overall sense of vigor and well being that may interact with a host of other psychologic changes associated with aging. Disordered erectile function is not generally an endocrine problem but rather vascular, neurologic, and psychogenic in origin. It also may be the first sign of systemic vascular disease. The clinical management of andropause requires an individualized approach. In some men, the main problem may be psychologic, whereas in others, hypogonadism may play an important role. Many with erectile failure, suffer silently regardless of its etiology. In this review, we suggest some practical guidelines for the management of these conditions.

Sexual dysfunction associated with antidepressant drugs

The term 'sexual dysfunction' describes a disturbance in sexual desire and the psychophysiological changes that characterise the normal sexual response cycle, and cause marked personal distress and interpersonal difficulty. Epidemiological studies indicate that sexual dysfunction is common in the general population, but more common in depressed individuals in community settings and clinical samples. Most antidepressant drugs have adverse effects on sexual function, but accurate identification of the incidence of treatment-emergent dysfunction has proved troublesome. Futhermore, investigations of sexual dysfunction associated with antidepressants have one or more methodological flaws. There may be some advantages for bupropion, moclobemide, nefazodone and reboxetine over other antidepressants. Many approaches have been adopted for management of patients with sexual dysfunction associated with antidepressant treatment, including waiting for the problem to resolve, behavioural strategies to modify sexual technique, individual and couple psychotherapy, delaying the intake of antidepressants until after sexual activity, reduction in daily dosage, 'drug holidays', use of adjuvant treatments, and switching to a different antidepressant.

Relevance of methodological design for the interpretation of efficacy of drug treatment of premature ejaculation: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis is to evaluate whether the design and methodology of drug-treatment studies of premature ejaculation affect the efficacy outcome differently. Therefore, methodological, design and efficacy data from 79 studies (3034 males), published between 1943 and 2003, are reviewed. A meta-analysis is performed on 43 selective serotonin reuptake inhibitors (SSRIs) and clomipramine studies (1514 males), published between 1973 and 2003; these studies were pooled to provide a summary variance-weighted effect size. The antidepressant-induced percentage increase of the intravaginal ejaculation latency time (IELT) was calculated and examined against various methodological items. A significant difference in efficacy between SSRIs was observed. Using daily treatment, paroxetine appeared more effective than the other SSRIs. Retrospective use of a questionnaire, subjective reports, single-blind and open study designs generate far greater variability of ejaculation time both at baseline and during active drug treatment than real time assessment by stopwatch. In conclusion, at daily treatment, the overall efficacy of paroxetine, clomipramine, sertraline and fluoxetine is comparable, but paroxetine exerts the strongest ejaculation delay. Only eight (18.5%) studies on antidepressant treatment fulfilled all criteria used in evidence-based medicine, for example, randomised, double-blind studies with prospective real time (stopwatch) assessment of the IELT at each intercourse. Single-blind studies, open designs, retrospective reporting, or the use of a questionnaire to assess ejaculation time should be avoided.

Pharmacologic management of sexual dysfunction: benefits and limitations

What is the current knowledge concerning the pharmacologic treatment of human sexual dysfunction? A number of interventions, including oral phophodiesterase inhibitors and intracorporeal agents with vasodilatory effects, are available to treat male erectile disorder. Serotonergic drugs have been shown to be effective in the treatment of rapid ejaculation. Various lines of research suggest that high dosages of androgenic agents may eventually have a role in the treatment of decreased libido in females. There may be a role for phophodiesterase inhibitors in the treatment of a subgroup of women with arousal disorders. Normal sexual function involves successful integration of biological, psychological, and interpersonal influences. Clinical psychiatry with its biopsychosocial model should incorporate the treatment of human sexual dysfunction within its purview.

The neurobiological approach to premature ejaculation

PURPOSE

Data showing the neurobiological background of rapid ejaculation was reviewed. In addition, new hypotheses to integrate clinical symptomatology, psychopharmacotherapy and psychotherapy of rapid ejaculation with brain function are provided.

MATERIALS AND METHODS

A computerized MEDLINE search, and manual bibliographic review of cross-references and neurobiological animal studies were performed. These reports were analyzed, summarized and compared with the studies performed by the author.

RESULTS

The literature on premature ejaculation published between 1887 and 2001 was reviewed. It appeared that the various psychological hypotheses and psychotherapies have not adequately been investigated. In contrast, psychopharmacological treatment studies, animal research data and stopwatch assessments in men with rapid (premature) ejaculation indicate that lifelong rapid ejaculation is a neurobiological phenomenon related to central serotonergic neurotransmission and likely influenced by hereditary factors.

CONCLUSIONS

Basic and clinical psychopharmacological studies suggest that premature ejaculation is a not a psychological disturbance but a neurobiological phenomenon.

Diagnosis and treatment of ejaculatory dysfunction

The normal ejaculatory process requires complex coordination and integration of neurologic, physiologic, anatomic, and psychologic events. An understanding of these processes is critical to evaluate properly and manage patients with ejaculatory dysfunction. With the advent of improved techniques to treat patients, some men with ejaculatory dysfunction are being offered the opportunity to reproduce. Further research on the ejaculatory process and associated dysfunctional states should continue to improve treatment for patients presenting with ejaculatory disorders.

Male sexual function and its disorders: physiology, pathophysiology, clinical investigation, and treatment

This review is designed to help the reproductive endocrinologist integrate his or her professional activity with those of other disciplines including urology, radiology, neurology, and psychology in order to successfully manage all of the inseparable aspects of male sexual and reproductive functioning. Significant advances in the field of male sexual physiology and pathophysiology and new methods of investigation and treatment of male sexual disorders are outlined. The review synthesizes available data on the following: norms of sexual organs, aging and sexuality, role of central and peripheral neurochemicals in each stage of the sexual cycle, role of corporeal smooth muscles in the hemodynamic control of erection and detumescence, influence of psychological factors, drugs, and disease on all aspects of sexual functioning, and use of nocturnal penile tumescence monitoring, imaging investigations, and neurophysiologic studies in the diagnostic workup of males with sexual dysfunction. Clinical algorithms are presented where appropriate. Extensive discussions on newly developed strategies in psychological and behavioral counseling, drug therapy, tissue engineering, nonsurgical devices, and surgical treatments for all forms of sexual disorders are also provided. Lastly, the effect of sexual dysfunction and its treatment on quality of life in affected men is addressed, along with recommendations for future research endeavors.

Ejaculatory physiology and dysfunction

The sequence of events encompassing ejaculation has been well described. Multiple disease processes can result in ejaculatory dysfunction. Evaluation and subsequent treatment of ejaculatory dysfunction is possible using behavioral, mechanical, and medical and surgical modalities. Further elucidation of ejaculation is now taking place at the molecular level.

Contextual approaches to the physiology and classification of erectile function, erectile dysfunction, and sexual arousal

This paper offers a reexamination of some long-held beliefs relating to the physiology of erectile function and dysfunction, including the idea that there is a singular physiology of erection. Rather, there appear to be plural neural, neurochemical, and endocrine mechanisms whose participation in erectile function depends on the behavioral context in which erection occurs. The best examples of this context-dependent physiology come from research on rats. For example, the medial amygdala is essential for noncontact erection in response to inaccessible estrous females, but not for erection during copulation. Also, androgen is necessary for touch-based and noncontact erection, but not for erection during copulation. Even the specific dopamine receptors important to erection may differ, depending on the context. If there is not a singular physiology of erection, then it follows that the physiology of erectile dysfunction may also vary from context to context. Thus, some disorders of the central nervous system may not be manifested in sleep-related erection, and therefore may be misinterpreted as "psychogenic" erectile dysfunction. This term belies the axiom that all psychological processes have a somatic basis; therefore, there can be no psychogenic dysfunction that does not involve organic processes which may respond to pharmacotherapy. A revised classification of erectile dysfunction based on this premise is offered. Finally, closer attention to erectile context may also illuminate male "sexual arousal" and its relation to "sexual motivation". The former term has so many meanings in current usage as to impede research, especially into the physiology of sexual arousal, which depends on comparisons between animals and humans. It is proposed that attention be given to two variables: whether or not erection occurs and whether or not the context is sexual. The occurrence of penile erection within a sexual context is viewed as the only case in which sexual arousal may be inferred unambiguously.

[Sexual dysfunctions induced by serotonin reuptake inhibitors]

OBJECTIVE

To assess the incidence of serotonin reuptake inhibitor (SRI) antidepressant-induced sexual dysfunction (SD) and to compare the sexual side effects of SRI.

DESIGN

Naturalistic, prospective, observational study.

SETTING

Two urban health centers.

PATIENTS

235 outpatients (164 women, 71 males) who began treatment with some of the following SRI: fluoxetine, sertraline, paroxetine, citalopram and venlafaxine, who had engaged in regular sexual practices with stable partner, who were suffering from different mental disorders who were being treated with SRI. The assignment to each group was according to clinical criteria.

INTERVENTIONS

Patients completed questionnaires that allowed reporting of both SD induced by the illness and the treatment, evaluating changes in libido, arousal, and orgasm. The patients were observed over 6 months of treatment.

RESULTS

147 patients (62.6%) reported one or more SD related to SRI treatment. There were differences in the incidence between the different SRI: 39% with fluoxetine, 75.5% with paroxetine, 78.8% with sertraline, 28.9% with citalopram and 80% with venlafaxine. In 78.2% of patients the SD showed no improvement by the end of this period. In a predictive logistical regression model of the presence of SD induced by the SRI, the female category and the presence of previous sexual problems were favourable predictors and the treatment with paroxetine, sertraline or venlafaxine were increased the risk of SD.

CONCLUSIONS

SD is one of the most frequent and persistent SRI adverse effect. We recommended to inquiry about SD in patients who were treated with SRI. Significant differences were found in the occurrence of SD between the different SRI. Such data would be particularly valuable to physicians when choosing a specific antidepressant from this therapeutic group.

Pharmacological treatment of premature ejaculation

Ejaculatory dysfunction is the most common male sexual disorder and premature ejaculation the most common presentation of ejaculatory dysfunction. Convincing data are lacking from controlled clinical studies to support sustainable long term efficacy of psychosexual counselling in the management of premature ejaculation. The pharmacological treatment of premature ejaculation is now receiving increased attention from both physicians with an interest in sexual medicine and from the pharmaceutical industry.

Selective serotonin reuptake inhibitors and neuroendocrine function

Selective serotonin (5-HT) reuptake inhibitors (SSRIs) are effective drugs for the treatment of several neuropsychiatric disorders associated with reduced serotonergic function. Serotonergic neurons play an important role in the regulation of neuroendocrine function. This review will discuss the acute and chronic effects of SSRIs on neuroendocrine function. Acute administration of SSRIs increases the secretion of several hormones, but chronic treatment with SSRIs does not alter basal blood levels of hormones. However, adaptive changes are induced by long-term treatment with SSRIs in serotonergic, noradrenergic and peptidergic neural function. These adaptive changes, particularly in the function of specific post-synaptic receptor systems, can be examined from altered adrenocorticotrophic hormone (ACTH), cortisol, oxytocin, vasopressin, prolactin, growth hormone (GH) and renin responses to challenges with specific agonists. Neuroendocrine challenge tests both in experimental animals and in humans indicate that chronic SSRIs produce an increase in serotonergic terminal function, accompanied by desensitization of post-synaptic 5-HT1A receptor-mediated ACTH, cortisol, GH and oxytocin responses, and by supersensitivity of post-synaptic 5-HT2A (and/or 5-HT2C) receptor-mediated secretion of hormones. Chronic exposure to SSRIs does not alter the neuroendocrine stress-response and produces inconsistent changes in alpha2 adrenoceptor-mediated GH secretion. Overall, the effects of SSRIs on neuroendocrine function are dependent on adaptive changes in specific neurotransmitter systems that regulate the secretion of specific hormones.

Effects of SSRIs on sexual function: a critical review

Sexual problems are highly prevalent in both men and women and are affected by, among other factors, mood state, interpersonal functioning, and psychotropic medications. The incidence of antidepressant-induced sexual dysfunction is difficult to estimate because of the potentially confounding effects of the illness itself, social and interpersonal comorbidities, medication effects, and design and assessment problems in most studies. Estimates of sexual dysfunction vary from a small percentage to more than 80%. This article reviews current evidence regarding sexual side effects of selective serotonin reuptake inhibitors (SSRIs). Among the sexual side effects most commonly associated with SSRIs are delayed ejaculation and absent or delayed orgasm. Sexual desire (libido) and arousal difficulties are also frequently reported, although the specific association of these disorders to SSRI use has not been consistently shown. The effects of SSRIs on sexual functioning seem strongly dose-related and may vary among the group according to serotonin and dopamine reuptake mechanisms, induction of prolactin release, anticholinergic effects, inhibition of nitric oxide synthetase, and propensity for accumulation over time. A variety of strategies have been reported in the management of SSRI-induced sexual dysfunction, including waiting for tolerance to develop, dosage reduction, drug holidays, substitution of another antidepressant drug, and various augmentation strategies with 5-hydroxytryptamine-2 (5-HT2), 5-HT3, and alpha2 adrenergic receptor antagonists, 5-HT1A and dopamine receptor agonists, and phosphodiesterase (PDE5) enzyme inhibitors. Sexual side effects of SSRIs should not be viewed as entirely negative; some studies have shown improved control of premature ejaculation in men. The impacts of sexual side effects of SSRIs on treatment compliance and on patients' quality of life are important clinical considerations.