Current perspectives on intracavernosal pharmacotherapy for erectile dysfunction

Pathophysiology and Grayscale Ultrasonography of Penile Corporal Fibrosis

INTRODUCTION

Penile corporal fibrosis may occur secondary to explantation of an infected penile prosthesis, severe penile trauma, refractory low-flow priapism, Peyronie's disease, or chronic intra-cavernous injection of vasoactive drugs. Other etiologies of corporal fibrosis, presenting primarily with erectile dysfunction, can develop in chronic smokers, hypertensive patients, alcoholics, diabetics, and after radical prostatectomy. Corporal erectile tissue fibrosis is a significant pathophysiologic component of erectile dysfunction; however, current ultrasound-based penile imaging protocols do not directly assess it.

OBJECTIVE

To determine if grayscale ultrasonography (US) is a suitable imaging modality to identify and assess penile corporal erectile tissue fibrosis.

METHODS

A PubMed literature review was performed for studies that detailed ultrasonographic methods and findings of pathologies causing penile corporal fibrosis. Our main outcome measure was the ultrasonographic findings of pathologies causing penile corporal fibrosis.

RESULTS

Grayscale US demonstrates the capability to detect and localize the fibrotic changes of the corpora cavernosa. Ultrasonographic findings capture penile corporal tissue heterogeneity including diffuse, circumscribed, or localized patterns.

CONCLUSION

Overall, grayscale US may be a useful and convenient imaging modality to assess penile corporal fibrosis secondary to explantation of an infected penile prosthesis, priapism, penile trauma, chronic intra-cavernous injection of vasoactive drugs, diabetes, Peyronie's disease, and vascular disease. While limited by the skill and knowledge of the US operator, the combined knowledge of pathophysiology and US may help clinicians identify and manage the underlying etiology of penile corporal fibrosis. Kim J, Drury R, Morenas R et al. Pathophysiology and Grayscale Ultrasonography of Penile Corporal Fibrosis. Sex Med Rev 2022;10:99-107.

European Association of Urology Guidelines on Sexual and Reproductive Health-2021 Update: Male Sexual Dysfunction

CONTEXT

The present summary of the European Association of Urology (EAU) guidelines is based on the latest guidelines on male sexual health published in March 2021, with a last comprehensive update in January 2021.

OBJECTIVE

To present a summary of the 2021 version of the EAU guidelines on sexual and reproductive health.

EVIDENCE ACQUISITION

A literature review was performed up to January 2021. The guidelines were updated, and a strength rating for each recommendation was included based on either a systematic review of the evidence or a consensus opinion from the expert panel.

EVIDENCE SYNTHESIS

Late-onset hypogonadism is a clinical condition in the ageing male combining low levels of circulating testosterone and specific symptoms associated with impaired hormone production and/or action. A comprehensive diagnostic and therapeutic work-up, along with screening recommendations and contraindications, is provided. Erectile dysfunction (ED) is the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance. Along with a detailed basic and advanced diagnostic approach, a novel decision-making algorithm for treating ED in order to better tailor therapy to individual patients is provided. The EAU guidelines have adopted the definition of premature ejaculation (PE), which has been developed by the International Society for Sexual Medicine. After the subtype of PE has been defined, patient's expectations should be discussed thoroughly and pharmacotherapy must be considered as the first-line treatment for patients with lifelong PE, whereas treating the underlying cause must be the initial goal for patients with acquired PE. Haemospermia is defined as the appearance of blood in the ejaculate. Several reasons of haemospermia have been acknowledged; the primary goal over the management work-up is to exclude malignant conditions and treat any other underlying cause.

CONCLUSIONS

The 2021 guidelines on sexual and reproductive health summarise the most recent findings, and advise in terms of diagnosis and treatment of male hypogonadism and sexual dysfunction for their use in clinical practice. These guidelines reflect the multidisciplinary nature of their management.

PATIENT SUMMARY

Updated European Association of Urology guidelines on sexual and reproductive health are presented, addressing the diagnosis and treatment of the most prevalent conditions in men. Patients must be fully informed of all relevant diagnostic and therapeutic options and, together with their treating physicians, decide on optimal personalised management strategies.

Pharmacology and perspectives in erectile dysfunction in man

Penile erection is a perfect example of microcirculation modulated by psychological factors and hormonal status. It is the result of a complex neurovascular process that involves the integrative synchronized action of vascular endothelium; smooth muscle; and psychological, neuronal, and hormonal systems. Therefore, the fine coordination of these events is essential to maintain penile flaccidity or allow erection; an alteration of these events leads to erectile dysfunction (ED). ED is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity. A great boost to this research field was given by commercialization of phosphodiesterase-5 (PDE5) inhibitors. Indeed, following the discovery of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost, and many preclinical and clinical papers have been published in the last 10 years. This review is structured to provide an overview of the mediators and peripheral mechanism(s) involved in penile function in men, the drugs used in therapy, and the future prospective in the management of ED. Indeed, 30% of patients affected by ED are classified as "nonresponders," and there is still an unmet need for therapeutic alternatives. A flowchart suggesting the guidelines for ED evaluation and the ED pharmacological treatment is also provided.

Rehabilitation of the cavernous smooth muscle in patients with organic erectile dysfunction

This study aimed at assessing the effect of regular use of intracorporeal injection (ICI), sildenafil citrate and vacuum constriction device (VCD) on cavernous smooth muscle and erectile activity. One hundred and sixty-five patients with organic erectile dysfunction were investigated for 3 months. The patient and his partner were classified prospectively after proper counselling: group I (n = 56) received ICI twice per week; group II (n = 55) received sildenafil 100 mg twice per week; and group III (n = 54) used VCD twice per week. Duplex ultrasound was carried out before and after treatment, and then, the patients were followed up for a month to assess the resumption of unaided erection. The results showed that there was significant improvement in mean peak systolic velocity (PSV) and mean cavernosal artery diameter (CAD) at the end of the treatment in all groups, being higher in the ICI group than in the other two groups. Also, the percentage of patients who resumed unaided intercourse were higher in the ICI group compared with the other two groups (17.9%, 9.1% and 3.7% respectively). It is concluded that repeated regular use of ICI, sildenafil or VCD by patients with organic erectile dysfunction has a positive impact on their cavernous blood flow and erectile activity.

Diabetes-induced erectile dysfunction: epidemiology, pathophysiology and management

Erectile dysfunction (ED) is defined as the inability of the male to attain and maintain erection of penis sufficient to permit satisfactory sexual intercourse. Prevalence of impotence in diabetic men is ≥50%. The pathophysiology of diabetes-induced erectile dysfunction (DIED) is multifactorial and no single etiology is at the forefront. The proposed mechanisms of erectile dysfunction in diabetic patients includes elevated advanced glycation end-products, increased levels of oxygen free radicals, impaired nitric oxide synthesis, increased endothelin B receptor binding sites and up-regulated RhoA/Rho-kinase pathway, neuropathic damage and impaired cyclic guanosine monophosphate (cGMP)-dependent protein kinase-1. The treatment of DIED is multimodal. Treatment of the underlying hyperglycemia and comorbidities is of utmost importance to prevent or halt the progression of disease. Oral medications are considered as the first line therapy for management of DIED. If oral agents cannot be used or have insufficient efficacy despite appropriate dosing and education, second-line treatments should be addressed. When there is lack of efficacy or when there is dissatisfaction with other modalities, penile prostheses are often the best alternative for ED and are considered as the third line therapy for DIED. Future strategies in the evolution of the treatment of DIED are aimed at correcting or treating the underlying mechanisms of DIED.

Vasoactive intestinal polypeptide/phentolamine for intracavernosal injection in erectile dysfunction

Erectile dysfunction (ED) is becoming an increasingly common problem and although oral therapies offer first-line treatment for many men, they are contraindicated or ineffective in substantial groups of patients. Intracavernosal injection (ICI) therapy is the most effective nonsurgical treatment for ED and offers an effective alternative to oral therapy. Sufficient arterial blood supply and a functional veno-occlusive mechanism are prerequisites in the attainment and maintenance of a functional erection. Invicorp (Plethora Solutions, London, UK) is a combination of vasoactive intestinal polypeptide (VIP) 25 microg and phentolamine mesylate 1 or 2 mg for ICI in the management of moderate to severe ED. The two active components have complementary modes of action; VIP has a potent effect on the veno-occlusive mechanism, but little effect on arterial inflow, whereas phentolamine increases arterial blood flow with no effect on the veno-occlusive mechanism. Clinical studies showed that Invicorp is effective in >or=80% of men with ED, including those who have failed to respond to other therapies and, unlike existing intracavernosal therapies, is associated with a very low incidence of penile pain and virtually negligible risk of priapism. We estimate that there are >5.9 million men in the USA alone for whom oral ED drugs are not a viable treatment option, and for whom Invicorp might offer a safe and effective alternative.

Injection therapy for the treatment of erectile dysfunction: a comparison between alprostadil and a combination of vasoactive intestinal polypeptide and phentolamine mesilate

OBJECTIVE

To compare two injectable treatments, alprostadil 5-20 microg powder for injection and a combination of vasoactive intestinal polypeptide (VIP) and phentolamine in patients with erectile dysfunction (ED).

DESIGN AND METHODS

This was an open multicentre, randomised crossover study comprising two phases. The first phase established the dose of each drug required to produce an erection suitable for sexual intercourse (grade 3 erection). In phase 2, responders to both drugs received, in random order, four doses of VIP/phentolamine, presented as ampoules, and four doses of alprostadil, presented as powder for injection. This was followed by four doses of VIP/phentolamine, presented in an autoinjector. In both phases, patient preference was assessed for each preparation.

RESULTS

187 patients were recruited. In the first phase, both treatments were effective, (83% alprostadil vs. 73% VIP/phentolamine, p = 0.002) but more patients preferred VIP/phentolamine (69 vs. 31%, p = 0.011). In phase 2 (n = 107), the proportion of injections that produced a grade 3 erection was similar for all three treatments (83-85%), but both presentations of VIP/phentolamine (ampoule and auto-injector) were preferred by significantly more patients (p < 0.001). Compared with both presentations of VIP/phentolamine, alprostadil produced a higher frequency of pain (28% of injections vs. 3% for each VIP/phentolamine presentation; p < 0.001) and a lower frequency of facial flushing (3 vs. 16-17%; p < 0.001).

CONCLUSIONS

VIP/phentolamine and alprostadil were effective treatments for ED, however the VIP/phentolamine combination was preferred by more patients, which may be because it was much less likely to cause pain.

Pathophysiology and treatment of diabetic erectile dysfunction

The pathophysiology of diabetes is multifactorial and no single etiology is at the forefront. The proposed mechanisms of erectile dysfunction (ED) in diabetic patients includes elevated advanced glycation end-products (AGEs) and increased levels of oxygen free radicals, impaired nitric oxide (NO) synthesis, increased endothelin B receptor binding sites and ultrastructural changes, upregulated RhoA/Rho-kinase pathway, NO-dependent selective nitrergic nerve degeneration and impaired cyclic guanosine monophosphate (cGMP)-dependent kinase-1 (PKG-1). The treatment of diabetic ED is multimodal. Treatment of the underlying hyperglycemia and comorbidities is of utmost importance to prevent or halt the progression of the disease. The peripherally acting oral phosphodiesterase type 5 (PDE5) inhibitors are the mainstay of oral medical treatment of ED in diabetics. Vacuum erection devices are an additional treatment as a non-invasive treatment option. Local administration of vasoactive medication via urethral suppository or intracorporal injection can be effective with minimal side-effects. Patients with irreversible damage of the erectile mechanism are candidates for penile implantation. Future strategies in the evolution of the treatment of ED are aimed at correcting or treating the underlying mechanisms of ED. With an appropriate vector, researchers have been able to transfect diabetic animals with agents such as neurotrophic factors and nitric oxide synthase (NOS). Further studies in gene therapy are needed to fully ascertain its safety and utility in humans.

The real-life safety and efficacy of vardenafil: an international post-marketing surveillance study--results from 29 358 German patients

We assessed the safety, efficacy and patient acceptability of vardenafil (Levitra, Bayer HealthCare, Leverkusen, Germany) under real-life conditions in patients with erectile dysfunction (ED) in a multinational post-marketing surveillance study. An initial and up to two follow-up visits were documented for 29 358 German ED patients receiving vardenafil. Patients were interviewed about overall treatment success, and individual sexual attempts were evaluated in a patient questionnaire. Overall erectile improvement was reported by 93.9% of physicians, and similar improvement rates were reported for both 10 mg and 20 mg vardenafil dosages. Most patients experienced improved erections after the first (73.6%) or second (88.5%) tablet. Sexual attempts were successful with respect to partner penetration in 94.9% of patients and with respect to maintenance of erection during intercourse in 87.7% of patients. Adverse drug reactions were very rare (1.3% of patients). Vardenafil was highly effective, reliable and well tolerated in ED patients treated under real-life conditions.

Combining programmed intracavernous PGE1 injections and sildenafil on demand to salvage sildenafil nonresponders

In a prospective, placebo-controlled, one group crossover design study, we tested whether adding programmed intracavernous PGE1 injections (IC-PGE1) can improve the effectiveness of sildenafil in erectile dysfunction (ED) patients unresponsive to monotherapy with this drug. In all, 40 ED patients who had experienced unsatisfactory erections with both the 50 and 100 mg sildenafil doses were treated with four bi-weekly 20 microg IC-PGE1 injections given in the clinic and provided with either placebo or 50 mg sildenafil capsules for the next 4 weeks. Thereafter, they were crossed over to the other oral treatment for an additional 4-week period. The IIEF-Erectile Function domain score (IIEF-EFS), the main outcome measure, was found considerably higher (P<0.001) with the combined IC-PGE1-50 mg sildenafil treatment than with IC-PGE1-placebo or sildenafil alone (50 or 100 mg) in a subset of 26 subjects (65%). They thus shifted from the 'severe' or 'moderate' to the 'mild' grading of ED classification.

Clinical and sonographic assessment of the side effects of intracavernous injection of vasoactive substances

The objective of this study is to evaluate the side effects of intracavernous vasoactive agents on clinical and sonographic basis. Two groups of patients were included, group I included 168 ED patients trained on self-injection therapy using one of the three protocols. Protocol A: papaverine; protocol B: PGE1; and protocol C: trimix (papaverine, phentolamine and PGE1). Patients were followed up clinically, sonographically and by laboratory investigations for 6 months to evaluate the occurrence of side effects. Group II included 21 patients presenting to our department for the first time with a complication of intracavernous injection pharmacotherapy (ICI) initiated elsewhere. In all, 168 patients of group I completed the study. Patients on papaverine had the highest incidence of complications concerning prolonged erection, subcutaneous hematoma and penile fibrosis. Postinjection penile pain was observed more with groups B and C than group A. No systemic side effects were reported. Duplex ultrasound was beneficial in detecting mild clinically impalpable fibrosis. In total, 10 patients of group II presented with prolonged erection, seven with penile fibrosis, three with cavernositis and one with intracavernous needle breakage. We conclude that although ICI therapy is an effective second-line treatment option, patients on a self-injection program should be followed up both clinically and sonographically both at the initiation phase and on regular follow-up visits.

New achievements and pharmacotherapeutic approaches to impotence in the elderly

Erectile dysfunction (ED) has a negative impact on the quality of life of elderly men, but impotence is not an absolute concomitant of aging. Aging changes influencing sexual function in men consist of a decreased capacity to reach arousal by imagination or view, fragility of erection, and an increase in the refractory period. These events may be part of the andropause syndrome, which includes a decrease in intellectual activity, fatigue, depression, decreases in body hair, lean body mass and bone mineral density, accompanied by an increase in weight. As a consequence, the overlap of aging processes, concurrent diseases and social situations to which elderly men are subject, results in the great variability reported in epidemiological studies. In the same way, the complex physiology of erection depends on the social, environmental, or physical context in which it occurs. New achievements in research on intracellular mechanisms of erection and on the neuroendocrinology of aging contribute to better understanding the pathophysiology of ED in the elderly. For example, testosterone declines with age with great interindividual variability, since other hormonal changes are also involved. What currently can be easily identified is the alteration of LH-testosterone feedback alterations, although hormone levels fall in the normal range. Nevertheless, the extent to which age-dependent decline in hormones leads to health problems that may affect the quality of life remains to be clarified. Several concepts on aging-related processes have been challenged, and conditions that were once accepted as physiologically age-related are now thought to lead to medical problems, but until now erectile dysfunction remains underreported, underdiagnosed, and undertreated, especially in the elderly. Nowadays, we are witnessing a rapid growth in available pharmacotherapies, from intracavernous injections of vasoactive drugs, to powerful new oral agents, with differing pharmacological dynamic and kinetic properties. New options for treatment are therefore possible, taking into account both the possibility of changing ineffective drugs and augmenting efficacy by means of synergistic associations. This rich generation of progress is certainly contributing to a better medical approach to sexuality in aging people.

Topical alprostadil cream for the treatment of erectile dysfunction: a combined analysis of the phase II program

OBJECTIVES

To present a meta-analysis of the efficacy and safety data of two recently completed Phase II studies examining a novel alprostadil topical cream for the treatment of erectile dysfunction (ED).

METHODS

Patients (n = 303) with ED of at least 3 months' duration were randomized to receive placebo or 50, 100, 200, or 300 microg alprostadil in two nearly identical 11-dose, multicenter, at-home studies of a novel topical cream containing alprostadil and a proprietary skin permeation enhancer. The primary efficacy endpoint was the change in erectile function domain score from baseline to the final visit. Secondary endpoints included changes in scores for questions 3 and 4 of the International Index of Erectile Function and standard diary analyses. Safety was assessed by analysis of adverse events, changes in laboratory test results, and physical examination findings.

RESULTS

The mean baseline parameters for the erectile function score, ED history, and secondary diagnoses suggested no significant differences among the treatment groups. The changes from baseline to the final visit erectile function scores were 0.98 +/- 0.84, 3.4 +/- 1.3, 3.4 +/- 0.88 (P <0.05), 5.3 +/- 0.92 (P <0.001), and 9.4 +/- 1.43 (P <0.001) for the ascending dose groups. Most secondary efficacy endpoints were significant for the 200 and 300-microg dose groups. Dose-related trends in efficacy were observed. Adverse events were localized to the application site, were of mild or moderate intensity, and were of short duration.

CONCLUSIONS

These results suggest topical alprostadil cream, when combined with a novel dermal permeation-enhancer, to be a potentially useful agent for the treatment of ED.

The efficacy and tolerability of vardenafil, a new, oral, selective phosphodiesterase type 5 inhibitor, in patients with erectile dysfunction: the first at-home clinical trial

Vardenafil, a novel selective phosphodiesterase type 5 inhibitor, was evaluated in its first large-scale at-home trial. A total of 601 men with mild to severe erectile dysfunction (ED) were enrolled in this multi-centre, randomized, double-blind, placebo-controlled trial of 12 weeks of treatment with either placebo or 5, 10 and 20 mg of vardenafil. Primary endpoints were Q3 (vaginal penetration) and Q4 (maintenance of erection) of the International Index of Erectile Function (IIEF). In the intent-to-treat population (n=580), the changes from baseline for 5, 10 and 20 mg vardenafil (1.2, 1.3 and 1.5, respectively) were all improved (P<0.001) over placebo (0.2) for Q3 and were similarly improved for Q4 (1.4, 1.5 and 1.7) compared to placebo (0.5) (P<0.001). All vardenafil doses improved all IIEF domains compared to placebo (P<0.001). The percentage of successful intercourses was between 71 and 75% for the three vardenafil doses. For the 20 mg dose, 80% of the patients experienced improved erections (GAQ) compared to 30% for placebo. Most frequent treatment-emergent adverse events were headache (7-15%), flushing (10-11%) and up to 7% for dyspepsia or rhinitis. Vardenafil treatment resulted in a high efficacy and low adverse-event profile in a population with mixed ED etiologies.