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

Erectile response profiles of men using PDE5 inhibitors combined with intracavernosal injections as part of a penile rehabilitation program after radical prostatectomy

BACKGROUND

Phosphodiesterase type 5 (PDE5) inhibitor labeling states that these agents should not be used in conjunction with other erectogenic medications for fear of priapism occurring.

AIM

We explored the risk of priapism and prolonged erections in men in our post-radical prostatectomy (RP) penile injection program who were using regular PDE5 inhibitor and intracavernosal injections (ICIs) as part of their rehabilitation program.

METHODS

The study cohort included men on penile injection therapy who (1) were taking tadalafil 5 mg daily or taking sildenafil 25 mg on noninjection days, (2) had an RP, (3) were using their respective PDE5 inhibitor regularly at the time of penile injection training, and (4) complied with the program instructions regarding penile injection use. Demographics, comorbidity details, PDE5 inhibitor dose and utilization, and injection dose and utilization data were collected. All patients underwent in-office injection training and used trimix (papaverine/phentolamine/prostaglandin E1) as the intracavernosal medication.

OUTCOMES

Priapism was defined as a patient self-reported penetration hardness erection ≥4 hours in duration, while prolonged erection was defined as a penetration hardness erection lasting ≥2 hours.

RESULTS

A total of 112 tadalafil users and 364 sildenafil users were compared. Mean age and duration post-RP were 62 ± 14 years and 5.2 ± 12 months, respectively, and there was no difference between tadalafil and sildenafil groups. The mean trimix dose was tadalafil 24 ± 24 units and sildenafil 31 ± 37 units (P < .05). Priapism occurred in 2 (1.7%) of 112 tadalafil users and 5 (1.4%) of 364 sildenafil users (P = .47). Excluding those men experiencing priapism on any occasion, those with any reported penetration hardness erection lasting ≥2 hours were 7 (6.3%) of 112 tadalafil users and 12 (3.3%) of 364 sildenafil users (P < .01). A total of 53% of these prolonged erections occurred within the first 6 injections at home (no difference between tadalafil and sildenafil groups).

CLINICAL IMPLICATIONS

We emphasize the need for continued monitoring and education on proper injection techniques to minimize the risk of adverse events in ICI and PDE5 inhibitor combination therapy.

STRENGTHS & LIMITATIONS

This study has a relatively large patient population with a considerable follow-up time. Additionally, the rigorous training, education, and monitoring of the participants, as well as the use of formal definitions for priapism and prolonged erections, enhances the accuracy and reliability of the results. However, there are some limitations, such as social desirability, confounding factors, and recall bias.

CONCLUSION

There is no significant difference in the incidence of priapism in an ICI program in which men combine ICI with tadalafil or sildenafil. However, tadalafil patients had a higher rate of prolonged erections, which was found to occur mostly early during the titration phase.

The management of erectile dysfunction in men with diabetes mellitus unresponsive to phosphodiesterase type 5 inhibitors

INTRODUCTION

Erectile dysfunction is associated with diabetes mellitus with an estimated prevalence of 52.5% in the diabetic population. The first-line therapy for erectile dysfunction is phosphodiesterase type 5 inhibitors, but data suggest that diabetic men may be less responsive than non-diabetic men. Thus, other treatments, including intracavernosal injections, intraurethral prostaglandin, vacuum erection devices and penile prosthetic surgery, should be considered in management of diabetic men with erectile dysfunction refractory to phosphodiesterase type 5 inhibitors. Furthermore, combination therapy of phosphodiesterase type 5 inhibitors and other oral treatments such as arginine or l-carnitine may have synergistic effects resulting in better outcomes. In addition, there are novel therapies such as low-intensity shockwave therapy and stem-cell therapy, which may also be effective in targeted treatment modalities. Furthermore, studies suggest that erectile dysfunction can be improved by targeting concurrent comorbidities or metabolic diseases such as depression, hypertension, hypogonadism, and dyslipidaemia. We present an evidence-based narrative review focusing on the management of erectile dysfunction in diabetic men who have not responded to phosphodiesterase type 5 inhibitors.

CONCLUSIONS

Both clinicians and patients should be aware of the different management options in diabetic patients who have not responded to phosphodiesterase type 5 inhibitors.

Frequency and anatomic distribution of arterial obstructions in patients with vasculogenic erectile dysfunction not responding to intracavernous prostaglandin

Background: The extent of arterial disease in patients with erectile dysfunction (ED) non-responsive to intracavernosal injection of Alprostadil is of importance for therapeutic options. However, published evidence, in particular angiographically validated is scarce. Here we investigated arterial lesion patterns in this specific patient cohort by selective angiography. Patients and methods: A cohort of 239 patients received a clinical and duplex-sonographic workup for ED of suspected vascular origin. Duplex ultrasound of the cavernosal arteries was performed after intracavernosal injection of 10 μg Alprostadil. Consequently, standardized workup included grading of the erectile and determination of peak systolic velocity (PSV) and end-diastolic velocity (EDV) in both cavernosal arteries. PSV-values below 30 cm/sec indicated reduced arterial flow, whereas EDV-values above 15 cm/sec indicated a venous leak of the pudendal veins. All patients with suspected arterial ED based on duplex sonography underwent contrast-enhanced computed tomography. Endovascular therapy was carried out in ED patients not responsive or with significant side effects to PDE-5-inhibitors or Alprostadil by selective angiographic depiction of erection-related arteries. Results: 54 patients with a mean age of 61.2 (±9.8) years underwent angioplasty of erectionr elated arteries. Out of these 48/54 (89%) patients presented with an erection considered insufficient for penetration (E0-E3) subsequent to intracavernous application of 10 μg Alprostadil. 14/48 (29%) patients had bilateral arterial obstructions and 34/48 (71%) had unilateral disease. Commonly affected was the internal pudendal artery (n = 31, 65%), followed closely by the common penile artery (n = 30, 64%). The least affected arteries were the dorsal penile (n = 6, 13%), hypogastric (n = 4, 8%), common iliac (n = 4, 8%), cavernosal (n = 4, 8%), and inferior gluteal (n = 1, 2%) arteries. Conclusions: Arterial obstructions amenable to endovascular revascularization are frequent in patients non-responsive to intracavernosal prostaglandin administration. Therapeutic strategies in ED patients non-responsive to conservative measures should therefore consider endovascular treatment opportunities.

Assessment of Combination Therapies vs Monotherapy for Erectile Dysfunction: A Systematic Review and Meta-analysis

IMPORTANCE

Combining 2 first-line treatments for erectile dysfunction (ED) or initiating other modalities in addition to a first-line therapy may produce beneficial outcomes.

OBJECTIVE

To assess whether different ED combination therapies were associated with improved outcomes compared with first-line ED monotherapy in various subgroups of patients with ED.

DATA SOURCES

Studies were identified through a systematic search in MEDLINE, Cochrane Library, and Scopus from inception of these databases to October 10, 2020.

STUDY SELECTION

Randomized clinical trials or prospective interventional studies of the outcomes of combination therapy vs recommended monotherapy in men with ED were identified. Only comparative human studies, which evaluated the change from baseline of self-reported erectile function using validated questionnaires, that were published in any language were included.

DATA EXTRACTION AND SYNTHESIS

Data extraction and synthesis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

MAIN OUTCOMES AND MEASURES

A meta-analysis was conducted that included randomized clinical trials that compared outcomes of combination therapy with phosphodiesterase type 5 (PDE5) inhibitors plus another agent vs PDE5 inhibitor monotherapy. Separate analyses were performed for the mean International Index of Erectile Function (IIEF) score change from baseline and the number of adverse events (AEs) by different treatment modalities and subgroups of patients.

RESULTS

A total of 44 studies included 3853 men with a mean (SD) age of 55.8 (11.9) years. Combination therapy compared with monotherapy was associated with a mean IIEF score improvement of 1.76 points (95% CI, 1.27-2.24; I2 = 77%; 95% PI, -0.56 to 4.08). Adding daily tadalafil, low-intensity shockwave therapy, vacuum erectile device, folic acid, metformin hydrochloride, or angiotensin-converting enzyme inhibitors was associated with a significant IIEF score improvement, but each measure was based on only 1 study. Specifically, the weighted mean difference (WMD) in IIEF score was 1.70 (95% CI, 0.79-2.61) for the addition of daily tadalafil, 3.50 (95% CI, 0.22-6.78) for the addition of low-intensity shockwave therapy, 8.40 (95% CI, 4.90-11.90) for the addition of a vacuum erectile device, 3.46 (95% CI, 2.16-4.76) for the addition of folic acid, 4.90 (95% CI, 2.82-6.98) for the addition of metformin hydrochloride and 2.07 (95% CI, 1.37-2.77) for the addition of angiotensin-converting enzyme inhibitors. The addition of α-blockers to PDE5 inhibitors was not associated with improvement in IIEF score (WMD, 0.80; 95% CI, -0.06 to 1.65; I2 = 72%). Compared with monotherapy, combination therapy was associated with improved IIEF score in patients with hypogonadism (WMD, 1.61; 95% CI, 0.99-2.23; I2 = 0%), monotherapy-resistant ED (WMD, 4.38; 95% CI, 2.37-6.40; I2 = 52%), or prostatectomy-induced ED (WMD, 5.47; 95% CI, 3.11-7.83; I2 = 53%). The treatment-related AEs did not differ between combination therapy and monotherapy (odds ratio, 1.10; 95% CI, 0.66-1.85; I2 = 78%). Despite multiple subgroup and sensitivity analyses, the levels of heterogeneity remained high.

CONCLUSIONS AND RELEVANCE

This study found that combination therapy of PDE5 inhibitors and antioxidants was associated with improved ED without increasing the AEs. Treatment with PDE5 inhibitors and daily tadalafil, shockwaves, or a vacuum device was associated with additional improvement, but this result was based on limited data. These findings suggest that combination therapy is safe, associated with improved outcomes, and should be considered as a first-line therapy for refractory, complex, or difficult-to-treat cases of ED.

Practical Approaches to Treat ED in PDE5i Nonresponders

Erectile dysfunction (ED) is a common sexual disorder in adult males and one of the most important factors affecting their quality of life and that of their partners. Although PDE5 inhibitors (PDE5is) are the first choice for improving erectile function, there is a substantial proportion of ED patients, termed PDE5i nonresponders, who do not respond to PDE5is. Because of the lack of effective therapies, these patients always have serious social and psychological problems due to ED, which should be addressed. Here, we review the available literature about ED and PDE5is and propose several strategies for mitigating ED in PDE5i nonresponders.

Non-invasive Management Options for Erectile Dysfunction When a Phosphodiesterase Type 5 Inhibitor Fails

Phosphodiesterase type 5 inhibitors (PDE5Is) are the drug of choice for medical management of erectile dysfunction (ED). On-demand PDE5Is have an overall efficacy of 60-70% for ED; 30-35% of patients fail to respond to a PDE5I, and 30-50% of non-responders can be salvaged with detailed counseling on proper use and physician follow-up to ensure that the patient has been prescribed an appropriate and full PDE5I clinical trial. True non-responders may be offered intracavernosal injections of erectogenic drugs, intraurethral alprostadil, or surgical insertion of a penile prosthesis. Such options are not discreet and are associated with more adverse effects than PDE5Is. Thus patients may request additional non-invasive medical management options. This review describes published literature on patients who failed to respond to an on-demand PDE5I regimen and were treated with a non-invasive PDEI-based regimen, including switching from one PDE5I to another; increasing the dose of PDE5I above the labeled dosage range; using two PDE5Is concurrently; using a daily PDE5I regimen; or combining a PDE5I with a testosterone supplement, α-adrenergic antagonist, intraurethral or intracavernosal alprostadil, vacuum erection device, or low-intensity shock wave therapy. The limitations of published clinical trials do not allow for sufficient evidence to recommend one option over another. Therefore, in PDE5I-refractory patients, the choice of a specific next step should be individualized based on the preference of the patient and his sexual partner, the advantages and disadvantages of the various options, the concurrent medical illnesses and medications of the patient, and the patient's response to treatment.

Combination therapy for erectile dysfunction involving a PDE5 inhibitor and alprostadil

The phosphodiesterase-5 inhibitors (PDE5Is) are the first-line treatment option for men with erectile dysfunction (ED), with alprostadil considered a second-line choice. Consideration has to be given to patients who fail these treatments and what their options are. This review evaluates the data on the combination of a PDE5I with alprostadil in patients who have previously failed therapy with either drug. A PubMed search was conducted and identified nine publications relating to combination treatment with alprostadil as intracavernosal, intraurethral or topical application. The results indicate that with all three formulations the combination therapy resulted in an improved outcome compared with either of the drugs as monotherapy. This was demonstrated by the increased total International Index of Erectile Function (IIEF) scores as well as IIEF erectile function domain scores. This finding was also valid for patients with post-prostatectomy ED. The associated side effects of the combined treatment did not result in treatment discontinuation. These findings suggest that combination therapy with a PDE5I and alprostadil might be considered a treatment option in patients who have previously had a poor response to either drug.

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.

Intracavernous administration of bone marrow mononuclear cells: a new method of treating erectile dysfunction?

While PDE5 inhibitors have revolutionized treatment of ED, approximately 30% of patients are non-responsive. A significant cause of this is vascular and smooth muscle dysfunction, as well as nerve atrophy. Autologous administration of bone marrow mononuclear cells (BMMC) has been performed in over 2000 cardiac patients without adverse effects, for stimulation of angiogenesis/regeneration. Despite its ease of access, and dependence on effective vasculature for function, comparatively little has been perform in terms of BMMC therapy for ED. Here we outline the rationale for use of autologous BMMC in patients with ED, as well as provide early safety data on the first use of this procedure clinically.

Treatment of erectile dysfunction and lower urinary tract symptoms by phosphodiesterase inhibitors

To date, it is widely accepted that several disorders of the male and female urogenital tract, such as erectile dysfunction, bladder overactivity, urinary stone disease, the benign prostatic syndrome, as well as symptoms of female sexual arousal and orgasmic dysfunctions, can be therapeutically approached by influencing the function of the smooth musculature of the respective organs. To achieve a pronounced drug effect without significant adverse events, a certain degree of tissue selectivity is mandatory. Selective intervention in intracellular pathways regulating smooth muscle tone has become the most promising strategy to modulate tissue and organ function. Since the concept of taking a pill to relieve symptoms of lower urinary tract dysfunction is now widely accepted following the successes of phosphodiesterase 5 (PDE5) inhibitor treatment of erectile dysfunction, the treatment of urological diseases has focused on orally available drugs acting via influencing intracellular signaling pathways, thereby combining a high response rate with the advantage of an on-demand intake. Specifically, the use of isoenzyme-selective PDE inhibitors offers great opportunities in the medical treatment of various genitourinary diseases. These agents are regarded to be safe and to be efficacious, i.e., having a fast onset of drug action and an improved effect-to-side-effect ratio. As experience with this class of compounds and their use in urology is rapidly growing, basic and clinical research in this field will most likely expand the pharmacological armamentarium of innovative treatment options in the next few years. The purpose of this review is to summarize current, as well as potential, upcoming indications for the use of PDE inhibitors in the pharmacotherapy of male erectile dysfunction and lower urinary tract symptoms.

Management of sildenafil treatment failures

PURPOSE OF REVIEW

Although oral type 5 phosphodiesterase inhibitors are considered as first-line therapy for the majority of causes of erectile dysfunction, because of their high efficacy, ease of use, and acceptable safety profile, there are some who fail to respond, mainly because of end-organ failure. This communication reviews the management of sildenafil failures in light of recent advances.

RECENT FINDINGS

Sildenafil failures can be attributed to either lack of efficacy or side effects; issues may involve the physician, patient, and his partner. Physicians may contribute to sildenafil failure and discontinuation because of inadequate instructions, lack of adequate follow-up, suboptimal dosing, lack of adequate trial, and insufficient clarification about safety issues. Studies have demonstrated that progression of endothelial dysfunction and diminished cavernosal smooth-muscle content are recognized organic factors which cause end-organ dysfunction and ultimately treatment failure.

SUMMARY

Proper counseling, medication optimization, and modifying associated risk factors can provide success in men who had initially failed sildenafil therapy for erectile dysfunction. Other treatment modalities that may be considered when sildenafil failure occurs include vacuum devices, intraurethral, and intracavernosal administration of vasoactive drugs alone or combined with sildenafil. Penile prosthesis implantation is considered as a last resort, if all first-line and second-line therapies fail.