Efficacy and safety of phosphodiesterase type 5 inhibitors on primary premature ejaculation in men receiving selective serotonin reuptake inhibitors therapy: a systematic review and meta‐analysis

We performed a systematic review and meta‐analysis to assess whether selective serotonin reuptake inhibitors (SSRIs) and phosphodiesterase type 5 inhibitors ( PDE5‐Is ) may have an additive therapeutic effect. A literature review was performed to identify all published randomised controlled trials (RCT) that used SSRIs combined with PDE5‐Is therapy for the treatment of primary PE. The search included the following databases: EMBASE, MEDLINE and the Cochrane Controlled Trials Register. The reference lists of the retrieved studies were also investigated. Five publications involving a total of 419 patients were used in the analysis, including 5 RCTs that compared PDE5‐Is plus SSRIs with SSRIs treating primary PE. Primary efficacy endpoints: IELT (the standardised mean difference (SMD) = 1.07, 95% confidence interval (CI) = 1.00 to 1.14, P < 0.00001) indicated that utilisation of PDE5‐Is and SSRIs was more effective than the SSRIs alone for a long time in patients with primary PE. Safety assessments included headache (odds ratio (OR) = 3.16, 95% CI = 1.63 to 6.11, P = 0.0006), and flushing indicated that PDE5‐Is plus SSRIs were well tolerated. This meta‐analysis indicates that PDE5‐Is combined with SSRIs seem to provide significantly better ejaculatory latency time as compared with SSRIs alone in patients with primary PE.     

Guidelines on Male Sexual Dysfunction: Erectile Dysfunction and Premature Ejaculation

Context

Erectile dysfunction (ED) and premature ejaculation (PE) are the two most prevalent male sexual dysfunctions.

Objective

To present the updated version of 2009 European Association of Urology (EAU) guidelines on ED and PE.

Evidence acquisition

A systematic review of the recent literature on the epidemiology, diagnosis, and treatment of ED and PE was performed. Levels of evidence and grades of recommendation were assigned.

Evidence synthesis

ED is highly prevalent, and 5–20% of men have moderate to severe ED. ED shares common risk factors with cardiovascular disease. Diagnosis is based on medical and sexual history, including validated questionnaires. Physical examination and laboratory testing must be tailored to the patient's complaints and risk factors. Treatment is based on phosphodiesterase type 5 inhibitors (PDE5-Is), including sildenafil, tadalafil, and vardenafil. PDE5-Is have high efficacy and safety rates, even in difficult-to-treat populations such as patients with diabetes mellitus. Treatment options for patients who do not respond to PDE5-Is or for whom PDE5-Is are contraindicated include intracavernous injections, intraurethral alprostadil, vacuum constriction devices, or implantation of a penile prosthesis.PE has prevalence rates of 20–30%. PE may be classified as lifelong (primary) or acquired (secondary). Diagnosis is based on medical and sexual history assessing intravaginal ejaculatory latency time, perceived control, distress, and interpersonal difficulty related to the ejaculatory dysfunction. Physical examination and laboratory testing may be needed in selected patients only.Pharmacotherapy is the basis of treatment in lifelong PE, including daily dosing of selective serotonin reuptake inhibitors and topical anaesthetics. Dapoxetine is the only drug approved for the on-demand treatment of PE in Europe. Behavioural techniques may be efficacious as a monotherapy or in combination with pharmacotherapy. Recurrence is likely to occur after treatment withdrawal.

Conclusions

These EAU guidelines summarise the present information on ED and PE. The extended version of the guidelines is available at the EAU Web site (http://www.uroweb.org/nc/professional-resources/guidelines/online/).     

Efficacy of type-5 phosphodiesterase inhibitors in the drug treatment of premature ejaculation: a systematic review

This review examines the role of nitric oxide (NO) as a neurotransmitter involved in the central and peripheral control of ejaculation, the methods of phosphodiesterase type 5 inhibitor (PDE5I) drug treatment studies for premature ejaculation (PE), the adherence of methods to the contemporary consensus of ideal PE drug trial design, the impact of methods on treatment outcomes and the role of PDE5Is in the treatment of PE. NO/cGMP transduction is involved in both the central and peripheral control of emission, but evidence for a direct central or peripheral effect of PDE5Is on ejaculation is speculative. Thirteen of the 14 studies reviewed failed to fulfil the evidence-based medicine criteria for ideal PE drug trial design. Limitations of the studies include inadequately defined study populations, the lack of a double-blind placebo-controlled study design, and the absence of consistent objective physiological measures or sensitive, validated outcome assessment instruments as study endpoints. The broad range of intravaginal ejaculatory latency time (IELT) fold-increases reported with PDE5Is, on-demand selective serotonin re-uptake inhibitor (SSRI) drugs, and combined PDE5I/on-demand SSRIs is testament to the unreliability of data and conclusions from methodologically flawed studies. The one study that fulfilled the evidence-based medicine criteria of an ideal clinical trial design reported that treatment with sildenafil failed to significantly increase baseline IELT, supporting our conclusion that there is no convincing evidence to support any role for PDE5Is in the treatment of men with lifelong PE and normal erectile function. However, there is limited evidence to support a potential role for PDE5Is alone or combined with daily or on-demand SSRIs in the treatment of acquired PE in men with comorbid erectile dysfunction. Further controlled studies adhering to the contemporary consensus of ideal clinical trial design are required to clarify the role of PDE5Is in this subgroup of men with acquired PE.     

Pharmacotherapy of premature ejaculation: a systematic review and network meta-analysis

Purpose

The purpose of the study was to conduct a systematic evaluation of the different general prescribed drugs for premature ejaculation (PE).

Methods

A systematic literature search of MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science for Systematic Reviews was performed on 1 March 2018. Intravaginal ejaculation latency time (IELT) was the main outcome. Analysis was performed under multivariate random-effects network model and efficacies of drugs were ranked with surface under the cumulative ranking (SUCRA) probabilities.

Results

A total of 48 studies were reviewed and 40 of them were further enrolled into network meta-analysis. The majority of RCTs were of unclear methodological quality. Pooled evidence suggested that topical anaesthetic creams (TAs), tramadol, selective serotonin reuptake inhibitors (SSRIs), and phosphodiesterase type 5 inhibitors (PDE5is) are more effective at prolonging IELT comparing with placebo. TAs (90%) on demand (OD) and PDE5is plus SSRI (89.8%) had the highest SUCRA, which meant the most probable to be the most effective intervention.

Conclusions

We recommend the initial use of dapoxetine 30 mg OD for PE because it has been tested in largest and better designed clinical trials rather than it is more effective than the other drugs studied. TAs and tramadol 50 mg OD can be used as a viable alternative to oral treatment with SSRIs. PDE5is combined with SSRIs are more effective than SSRIs monotherapy but are also associated with more side effects. PDE5is OD can be recommended to PE patients with ED.

     

The pharmacological treatment of premature ejaculation

Premature ejaculation (PE) is a common sexual dysfunction in men that is characterized by a short time to ejaculation, and a lack of control over ejaculation, and is associated with distress for men and their partners. Lack of knowledge about the aetiology of PE and lack of approved treatments might contribute to its under-diagnosis and under-treatment. The organic factors involved in PE are not well understood but serotonin (5-hydroxytryptamine, 5-HT) is important at the level of the central nervous system in the complex regulatory mechanisms involved in ejaculation. Selective serotonin reuptake inhibitor (SSRI) antidepressants (paroxetine, fluoxetine and sertraline) and the tricyclic antidepressant clomipramine increase ejaculatory control and delay ejaculation in men with PE, suggesting that pharmacological intervention might be useful for PE. These agents are intended for chronic dosing for treating psychiatric disorders because of their pharmacokinetic profile and pharmacodynamic activity, which might result in limitations when used for treating PE. Indeed, these properties might limit the utility of these drugs, whether administered on-demand or chronically, for the episodic treatment requirements of PE. Elevated synaptic 5-HT levels achieved with acute SSRI treatment might be self-limiting because of activation of presynaptic 5-HT(1A) autoreceptors, and chronic 5-HT(1A) autoreceptor desensitization might contribute to an increase in side-effects and withdrawal symptoms. Short-acting SSRIs such as dapoxetine, currently under development for the on-demand treatment of PE, might circumvent these limitations and offer better ejaculatory control and sexual satisfaction for men with PE. Phosphodiesterase-5 inhibitors have also been evaluated for treating PE, as have topical anaesthetics and the narcotic analgesic tramadol.     

Pharmaco-induced erections for penile color-duplex ultrasound: oral PDE5 inhibitors or intracavernosal injection?

To prospectively compare the clinical responses and penile color-duplex ultrasound (PCDU) results of oral PDE5 inhibitors (PDE5-Is) with papaverine intracavernosal injection (ICI) and to evaluate whether PDE5-Is could be used as alternatives to vasoactive agent injections, 25 ED patients underwent PCDU three times with an interval of at least 1 week, using different pharmacological induction: ICI mode (30-60?mg papaverine), sildenafil mode (100?mg sildenafil) and tadalafil mode (20?mg tadalafil). The preference of the patients was collected when all tests were completed. No significant differences were found in peak systolic velocity and acceleration time among all three modes. However for the ICI mode, end diastolic velocity of the right cavernosal artery was significantly higher than those of the sildenafil and tadalafil modes 5?min after erection induction, and at 15?min it became lower than those of two PDE5-I modes. Consequently, resistance index of the right cavernosal artery in ICI mode was reversed at 5 and 15?min. In all, 60.0 and 56.0% patients managed to reach full erection in PDE5-Is modes, which was significantly lower than in ICI mode (80.0%). Therefore, although PDE5-Is and papaverine ICI showed similar effects on PCDU parameters in detecting arterial ED, more patients had better clinical responses to ICI, and oral PDE5-Is administration still showed some pitfalls in practical use.     

Deleterious effects of selective serotonin reuptake inhibitor treatment on semen parameters in patients with lifelong premature ejaculation

Premature ejaculation (PE), the most common sexual dysfunctions in men, is characterized by loss or absence of ejaculatory control. PE can be classified as either a lifelong or acquired condition. Although the prevalence of lifelong PE is rather low in the general male population, recent studies demonstrated that the patients who seek treatment for their rapid ejaculation mostly report lifelong PE. Although no drug for PE has been approved by regulatory bodies, chronic selective serotonin reuptake inhibitors (SSRIs) proved to be effective in treating lifelong PE. Despite the rising use and known effects of antidepressants on ejaculation, only a few reports have evaluated the impact of these drugs on the male fertility. Thus, the aim of this review is to evaluate the efficacy and adverse effects of SSRIs on semen parameters of patients with lifelong PE as well as to assess the safety of this treatment among sexually active couples who desire to have a child.     

Premature ejaculation: state of the art

Premature ejaculation (PE) is a frequent male sexual complaint.This occurrence does not automatically imply the existence of a male sexual disorder. The current DSM definition of PE has a low positive predictive value with a high associated risk for false-positive diagnoses of PE. A new classification in four well-defined PE syndromes has recently been proposed for the pending DSM-V. According to this new classification there are different pathophysiologies and treatments of PE, dependent on the underlying PE syndrome. Some types are particularly neurobiologically or medically determined and need drug treatment; other types, which are mainly psychologically determined, need psychotherapy or both drug treatment and psychotherapy. A meta-analysis of all selective serotonin reuptake inhibitors (SSRIs) and clomipramine studies, which were performed according to current standards of evidence-based medicine, demonstrated a similar efficacy for the daily treatment with the serotonergic antidepressants paroxetine hemihydrate, clomipramine, sertraline, and fluoxetine, with paroxetine hemihydrate exerting the strongest effect on ejaculation. On-demand treatment with SSRIs generally exerts much less ejaculation delay than daily SSRI treatment. Other on-demand treatment options are the topical use of anesthetics, tramadol, and phosphodiesterase type 5 inhibitors. Caution is needed with tramadol with regard to its potential addictive properties. There is insufficient evidence for the ejaculation delaying effects of phosphodiesterase type 5 inhibitors and intracavernous injection of vasoactive drugs.     

Systematic review and meta-analysis on phosphodiesterase 5 inhibitors and α-adrenoceptor antagonists used alone or combined for treatment of LUTS due to BPH

The aim of this systematic review is to determine the comparative effectiveness and safety of phosphodiesterase 5 inhibitors (PDE5-Is) and α-blockers used alone or combined for the treatment of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). An electronic search of PubMed, Cochrane Library and Embase up to January 2014 was performed to identify randomized controlled trials comparing the efficacy and safety of PDE5-Is and α-blockers for treatment of lower urinary tract symptoms due to benign prostatic hyperplasia, which assessed IPSS score, maximum flow rate, postvoided residual urine, quality of life and Erectile Function (IIEF) score as outcomes. Data were analyzed by fixed or random effect models using Cochrane Collaboration review manager software. A total of 12 studies were included. Our novel data demonstrated that there was a trend that α-blockers were more efficacious than PDE5-Is on decreasing IPSS score and increasing maximum flow rate. α-blockers were significantly more effective than PDE5-Is on reduction of postvoided residual urine with a mean difference of 3.67 (95% CI 1.56 to 5.77, P = 0.0006) and PDE5-Is showed greater effect than α-blockers on increasing IIEF score with a mean difference of 9.82 (95% CI 3.80 to 15.85, P = 0.001). In conclusion, our novel data demonstrated that PDE5-Is plus ABs ranked the highest on the improvement of LUTS/BPH. PDE5-Is monotherapy was also effective in this kind of disorder except less reduction of PVR than ABs. In addition, both combined- or mono-therapy were safe.     

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.     

Critical analysis of the relationship between sexual dysfunctions and lower urinary tract symptoms due to benign prostatic hyperplasia

Context

This review focuses on the relationship among sexual dysfunction (SD), lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH), and related therapies.

Objective

We reviewed the current literature to provide an overview of current data regarding epidemiology and pathophysiology of SD and LUTS. Moreover, we analysed the impact of currently available therapies of LUTS/BPH on both erectile dysfunction (ED) and ejaculatory dysfunction and the effect of phosphodiesterase type 5 inhibitors (PDE5-Is) in patients with ED and LUTS.

Evidence acquisition

We conducted a Medline search to identify original articles, reviews, editorials, and international scientific congress abstracts by combining the following terms: benign prostatic hyperplasia, lower urinary tract symptoms, sexual dysfunction, erectile dysfunction, and ejaculatory dysfunction.

Evidence synthesis

We conducted a comprehensive analysis of more relevant general population-based and BPH/LUTS or SD clinic-based trials and evaluated the common pathophysiologic mechanisms related to both conditions. In a further step, the overall impact of current BPH/LUTS therapies on sexual life, including phytotherapies, novel drugs, and surgical procedures, was scrutinized. Finally, the usefulness of PDE5-Is in LUTS/BPH was critically analysed, including preclinical and clinical research data as well as possible mechanisms of action that may contribute to the efficacy of PDE5-Is with LUTS/BPH.

Conclusions

Community-based and clinical data demonstrate a strong and consistent association between LUTS and ED, suggesting that elderly men with LUTS should be evaluated for SD and vice versa. Pathophysiologic hypotheses regarding common basics of LUTS and SD as discussed in the literature are (1) alteration of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway, (2) enhancement of RhoA-Rho-kinase (ROCK) contractile signalling, (3) autonomic adrenergic hyperactivity, and (4) pelvic atherosclerosis. The most important sexual adverse effects of medical therapies are ejaculation disorders after the use of some α-blockers and sexual desire impairment, ED, and ejaculatory disorders after the use of α-reductase inhibitors. Minimally invasive, conventional, and innovative surgical treatments for BPH may induce both retrograde ejaculation and ED. PDE5-Is have demonstrated significant improvements in both LUTS and ED in men with BPH; combination therapy with PDE5-Is and α1-adrenergic blockers seems superior to PDE5-I monotherapy.     

A Novel Treatment of Premature Ejaculation

The investigation of the etiology and treatment of premature ejaculation (PE), a common and significant problem for men and their partners, has been limited by the lack of defined outcomes and differences in clinical trial designs. Currently, no medication has been approved for the treatment for PE worldwide. Recognition of serotonin as a key mediator in ejaculatory signaling has raised interest in the utility of pharmacologic intervention for treating PE. Selective serotonin reuptake inhibitors (SSRIs) have been used off-label for PE, with varied results. However, treatment with currently available SSRIs typically requires chronic dosing that increases drug accumulation and the attendant risk of adverse events. Dapoxetine is an SSRI with a short half-life (1.2 h), developed specifically for the treatment of men with PE. This agent has a unique pharmacokinetic profile characterized by rapid absorption and elimination. Dapoxetine is metabolized by multiple pathways, and no clinically relevant drug–drug interactions have been identified. Furthermore, dapoxetine pharmacokinetics do not appear to be affected by food, age, alcohol, or phosphodiesterase type 5 (PDE5) inhibitors to a relevant degree. In two placebo-controlled phase 3 trials involving >2600 men with PE, dapoxetine 60 mg given as needed over 12 wk significantly prolonged the stopwatch-assessed intravaginal ejaculatory latency time (IELT) from 0.91 min at baseline to 3.32 min (p < 0.0001), increased control over ejaculation, and increased sexual satisfaction for men and their partners compared with placebo (both p < 0.0001). These results suggest that dapoxetine may meet the medical need for on-demand therapy for PE.     

A meta-regression evaluating the effectiveness and prognostic factors of oral phosphodiesterase type 5 inhibitors for the treatment of erectile dysfunction

The effectiveness of phosphodiesterase type 5 inhibitors (PDE5-Is) for erectile dysfunction (ED) varies considerably among trials, but available studies investigating the factors that affect the effectiveness are few and findings are not consistent. A systematic search was performed in PubMed, Cochrane Library, and EMBASE to identify randomized controlled trials comparing PDE5-Is with placebo for the treatment of ED. The methodological quality of included studies was assessed by the Cochrane Collaboration''s tool for assessing risk of bias. The associations between prespecified study-level factors and effectiveness were tested by a random effects meta-regression model. This study included 93 trials with 26 139 patients. When all PDE5-Is were grouped together, Caucasian ethnicity was associated with 15.636% (95% confidence interval [CI]: 0.858% to 32.579%) increase in risk ratio (RR) for Global Assessment Questionnaire question-1 (GAQ-1), and 1.473 (95% CI: 0.406 to 2.338) score increase in mean difference (MD) for posttreatment International Index of Erectile Function-Erectile Function domain score (IIEF-EF), compared to Asian ethnicity. A one-score increase in baseline IIEF-EF was associated with −5.635% (95% CI: −9.120% to −2.017%) reduction in RR for GAQ-1, and −0.229 (95% CI: −0.425 to −0.042) score decrease in MD for posttreatment IIEF-EF. In conclusion, PDE5-Is are more effective in Caucasians than Asians, and in patients with more severe ED.     

Phosphodiesterase type 5 inhibitors: the day after

OBJECTIVE: Review the literature on phosphodiesterase type 5 inhibitors (PDE5-Is), addressing critical issues in their current and future use, assessing unanswered questions, and identifying research needs. METHODS: A MEDLINE search was conducted on PDE5-Is, with emphasis on clinical trials and experience, for interpretation and analysis of their present and future role. RESULTS: Although approximately 40 million patients with erectile dysfunction have been treated successfully worldwide with the three available PDE5-Is, inappropriate instructions, lack of follow-up, and lack of patient-centered care models are the main reasons for "non-response," leading to drop-out rates of >50%. Patients with severe neurologic damage, diabetes mellitus, or severe vascular disease may be resistant to PDE5-Is. Preservation of corporal smooth muscle with chronic administration of PDE5-Is has been reported and substantial evidence indicates that these drugs have beneficial effects on endothelium and cardiovascular function; sildenafil has been approved for the treatment of idiopathic pulmonary hypertension. Improvement of lower urinary tract symptoms in men with benign prostatic hyperplasia after PDE5-I administration has been also suggested. CONCLUSIONS: The data indicate the necessity for (1) exploration of the pharmacologic characteristics of the three PDE5-Is; (2) research on their pharmacologic differences because some actions seems to be drug-specific; (3) development of alternative management strategies, such as chronic, low, everyday doses of PDE5-Is, if the monthly cost is affordable; and (4) clinical trials on use of PDE5-Is to treat other chronic conditions. The door for innovative therapeutic approaches will open, specifically for cross-risk factor treatment with PDE5-Is or their use in combination treatments or new multimodal pills that take advantage of drugs that exert pleiotropic vascular actions.     

Combining testosterone and PDE5 inhibitors in erectile dysfunction: basic rationale and clinical evidences

INTRODUCTION: Erectile dysfunction (ED) and decline of testosterone levels are frequently observed with age and also in illnesses with a common basis of endothelial damage. OBJECTIVES: To review molecular mechanisms underlying androgen action upon its receptor and phosphodiesterase type 5 (PDE5) expression and regulation by testosterone in cavernous tissue and their clinical implication in the treatment of ED refractory to PDE5 inhibitors (PDE5-Is). METHODS: From January 2003 to May 2006 [corrected] we performed an extensive, unsystematic MEDLINE literature search reviewing relevant data on basic and clinical studies regarding the efficacy of combination therapies. RESULTS: Most trials using testosterone alone for treatment of ED in hypogonadal men suffer from methodologic problems and report inconsistent results, but overall the trials suggest that testosterone is superior to placebo. Orally effective PDE5-Is, such as sildenafil, tadalafil, or vardenafil, may be ineffective depending on the demonstration of testosterone regulation of PDE5 expression in human corpus cavernous, and their efficacy may be enhanced by testosterone adjunction whenever necessary. CONCLUSIONS: Screening for hypogonadism in all men with ED is necessary to identify men with severe hypogonadism and some cases of mild to moderate hypogonadism, who may benefit from testosterone treatment. Identification of threshold values for testosterone supplementation to appropriately benefit from PDE5-Is failure may improve clinical management of unresponsive patients with minimization of unwanted effects.     

Phosphodiesterase type 5 inhibitors in postprostatectomy erectile dysfunction: a critical analysis of the basic science rationale and clinical application

Context

Erectile dysfunction (ED) after radical prostatectomy (RP) has a significant negative impact on a patient's health-related quality of life. Phosphodiesterase type 5 inhibitors (PDE5-Is) have recently been utilized not only as a treatment of ED in this population but also as a preventive strategy in penile rehabilitation programs.

Objective

To elucidate the pathophysiologic mechanisms of post-RP ED, to assess the need for rehabilitation following surgery, and to analyze the basic scientific evidence and clinical applications of PDE5-Is for the prevention and treatment of ED.

Evidence acquisition

A systematic review of the literature using Medline, Cancerlit, and the Cochrane Library was conducted for the period between January 1997 and June 2008 using the keywords erectile dysfunction, radical prostatectomy, and phosphodiesterase inhibitors. Efficacy and safety of PDE5-Is in the randomized, placebo-controlled trials are evaluated in this review, and the limitations of the remaining studies are also discussed.

Evidence synthesis

Post-RP ED has many factors. Cavernosal nerve injury induces pro-apoptotic factors (ie, loss of smooth muscle) and pro-fibrotic factors (ie, an increase in collagen) within the corpora cavernosa. Cavernosal changes may also be attributed to poor oxygenation due to hemodynamic changes. Experimental data support the concept of cavernosal damage and suggest a protective role for daily dosage of a PDE5-I; however, similar data have not yet been replicated in humans. Penile rehabilitation programs are common in clinical practice, but there is no definitive evidence to support their use or the best treatment strategy. PDE5-Is are efficacious and safe in young patients with normal preoperative erectile function who have undergone bilateral nerve-sparing radical prostatectomy. On-demand use of a PDE5-I may be at least as efficacious as daily use. PDE5-I use in penile rehabilitation programs is not supported by rigorous level 1 evidence-based medicine.

Conclusions

PDE5-Is are an efficacious and safe treatment for post-RP ED in properly selected patients. The experimental results on the protective role of daily dosages of PDE5-Is, while robust, have not been replicated in humans. With current human data, the role of a PDE5-I alone as a rehabilitation strategy is unclear and deserves further investigation.     

The effects of three phosphodiesterase type 5 inhibitors on ejaculation latency time in lifelong premature ejaculators: a double-blind laboratory setting study

Study Type – Therapy (RCT)
Level of Evidence 1b What’s known on the subject? and What does the study add? Several authors have reported their experience with PDE5 inhibitors alone or in combination with selective serotonin re‐uptake inhibitors for treating premature ejaculation. However, to our knowledge, this is the first laboratory design study to evaluate the effects of three PDE5 inhibitors throughout the ejaculation process in men with lifelong premature ejaculation. In this laboratory setting study PDE5 inhibitors seem to prolong ELT but the difference from placebo is significant only in vardenafil. The quality of penile rigidity is better with PDE5 inhibitors in the post‐ejaculatory period but the difference is significant only in sildenafil and vardenafil.

OBJECTIVE

? To evaluate the effects of three phosphodiesterase type 5 (PDE5) inhibitors on the ejaculation process in men with lifelong premature ejaculation using a double‐blind laboratory setting.

PATIENTS AND METHODS

? Eighty men with lifelong premature ejaculation, 20 in each group, received placebo, vardenafil (10 mg), sildenafil (50 mg) or tadalafil (20 mg) in a double‐blind study design. Placebo or PDE5 inhibitor was ingested after at least 2 h fasting and non‐smoking. The subjects were placed in a silent room immediately and real‐time penile rigidity and tumescence was monitored. ? Subjects read some magazines or newspapers without any sexually stimulating material for 1.5 h. At the end of this period audiovisual sexual stimulation began with a video film and after the 8th minute the subject began vibratory stimulation to the frenular area. ? At the beginning of ejaculation the patient stopped stimulation. When the patient began and stopped stimulation, the light near the observer turned on and off and the observer calculated the ejaculation period with a chronometer. The elapsed time was the ejaculation latency time (ELT) in seconds. ? There was no interaction between subjects and observer during the test. The ELT, and the qualities of base and tip rigidities during ELT and after ejaculation were calculated.

RESULTS

? Median age of patients was 29 (range 22–39) years and median duration of premature ejaculation was 60 (range 7–180) months and there was no significant difference between groups. Median duration of vibratory stimulation (ELT) of subjects who received placebo was 48.5 s: 53.5 s for sildenafil, 70.0 s for tadalafil and 82.5 s for vardenafil. Compared with the placebo group, ELT was significantly longer only in subjects receiving vardenafil (P = 0.019). ? In the post‐ejaculatory refractory period, times to last recorded base rigidities were significantly longer than placebo in vardenafil and sildenafil groups with better erection quality (P < 0.01 for each).

CONCLUSIONS

? The PDE5 inhibitors seem to prolong ELT and the quality of penile rigidity is better with PDE5 inhibitors in post‐ejaculatory period. ? These findings suggest that PDE5 inhibitors might have some beneficial effects in men with lifelong premature ejaculation.     

Comparative Effectiveness and Safety of Oral Phosphodiesterase Type 5 Inhibitors for Erectile Dysfunction: A Systematic Review and Network Meta-analysis

Context

Phosphodiesterase type 5 inhibitors (PDE5-Is) are currently the first-line therapy for erectile dysfunction (ED), but available studies investigating the comparative effects of different PDE5-Is are limited.

Objective

To compare the efficacy and safety of different classes of oral PDE5-Is for ED.

Evidence acquisition

A systematic search was performed in PubMed, Cochrane Library, and Embase to identify randomized controlled trials that compared different PDE5-Is or PDE5-Is with a placebo for ED. The methodological quality of included studies was appraised with the Cochrane Collaboration bias appraisal tool, and the quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation system.

Evidence synthesis

A total of 118 trials (31 195 individuals) were included. There was no major difference in the results between the traditional meta-analysis and the network meta-analysis. Network meta-analysis demonstrated that PDE5-Is were superior to placebo to improve erectile function. Compared with tadalafil (relative risk [RR]: 0.61; 95% confidence interval [CI], 0.33–0.90) and vardenafil (RR: 0.63; 95% CI, 0.35–0.92), avanafil was less effective on Global Assessment Questionnaire question 1. Tadalafil was more effective than vardenafil (mean difference [MD]: 1.49; 95% CI, 0.50–2.50) and udenafil (MD: −1.84; 95% CI, −3.31 to −0.33) as measured by the erectile function domain of the International Index of Erectile Function. For all efficacy outcomes, the absolute effects and the rank tests indicated that tadalafil and vardenafil were the most effective agents. After adjusting for dosage, the conclusion remained the same. Safety analysis showed there was no major difference among different agents.

Conclusions

In recommended doses, oral PDE5-Is are more effective than placebo for ED, and tadalafil seems to be the most effective agent, followed by vardenafil. PDE5-Is are generally safe and well tolerated, and there is no major difference on the safety profile.