Efficiency and side effects of intracavernous injections of moxisylyte in impotent patients: a dose-finding study versus placebo

Erectile Dysfunction: Treatments, Advances and New Therapeutic Strategies

Erectile dysfunction (ED) is the inability to get and maintain an adequate penile erection for satisfactory sexual intercourse. Due to its negative impacts on men's life quality and increase during aging (40% of men between 40 and 70 years), ED has always attracted researchers of different disciplines, from urology, andrology and neuropharmacology to regenerative medicine, and vascular and prosthesis implant surgery. Locally and/or centrally acting drugs are used to treat ED, e.g., phosphodiesterase 5 inhibitors (first in the list) given orally, and phentolamine, prostaglandin E1 and papaverine injected intracavernously. Preclinical data also show that dopamine D4 receptor agonists, oxytocin and α-MSH analogues may have a role in ED treatment. However, since pro-erectile drugs are given on demand and are not always efficacious, new strategies are being tested for long lasting cures of ED. These include regenerative therapies, e.g., stem cells, plasma-enriched platelets and extracorporeal shock wave treatments to cure damaged erectile tissues. Although fascinating, these therapies are laborious, expensive and not easily reproducible. This leaves old vacuum erection devices and penile prostheses as the only way to get an artificial erection and sexual intercourse with intractable ED, with penile prosthesis used only by accurately selected patients.

Blue laser-induced selective vasorelaxation by the activation of NOSs

Phototherapy has been tried for treating cardiovascular diseases. In particular, ultraviolet and blue visible lights were suggested to be useful due to their nitric oxide (NO)-production ability in the skin. However, the effects of blue light on the arterial contractility are controversial. Here, we hypothesized that appropriate protocol of blue laser can induce selective vasorelaxation by activating vasodilating signaling molecules in arteries. Using organ chamber arterial mechanics, NO assay, Matrigel assay, and microarray, we showed that a 200-Hz, 300-μs, 445-nm pulsed-laser (total energy of 600 mJ; spot size 4 mm) induced selective vasorelaxation, without vasocontraction in rat mesenteric arteries. The laser stimulation increased NO production in the cord blood-endothelial progenitor cells (CB-EPCs). Both the laser-induced vasorelaxation and NO production were inhibited by a non-selective, pan-NO synthase inhibitor, L-NG-Nitro arginine methyl ester. Microarray study in CB-EPCs suggested up-regulation of cryptochrome (CRY)2 as well as NO synthase (NOS)1 and NOSTRIN (NOS trafficking) by the laser. In conclusion, this study suggests that the 445-nm blue puled-laser can induce vasorelaxation possibly via the CRY photoreceptors and NOSs activation. The blue laser-therapy would be useful for treating systemic hypertension as well as improving local blood flow depending on the area of irradiation.

Performance and safety of treatment options for erectile dysfunction in patients with spinal cord injury: A review of the literature

BACKGROUND

For a large proportion of patients with spinal cord injury, sexuality and reproduction are important issues. However, sparse data exist regarding available treatment options for this patient population.

OBJECTIVES

We sought to review performance and safety rates of all currently available treatment options for erectile dysfunction in spinal cord injury men.

MATERIALS AND METHODS

A systematic literature review without time restrictions was performed using PubMed/EMBASE database for English-, Italian-, German-, and Spanish-language articles. Articles' selection was performed according to the PRISMA guidelines. Relevant papers on erectile dysfunction in spinal cord injury patients were included in the final analyses.

RESULTS AND DISCUSSION

Overall, 47 studies were eligible for inclusion in this review. Of these, most evidence dealt with phosphodiesterase 5-inhibitors and intracavernous drug injection. Both treatment options are associated with high levels of performance and with patients/partners' satisfaction; side effects are acceptable. Overall, penile prostheses and vacuum erection devices are in general less approved by spinal cord injury patients and are correlated with increased rates of complications in comparison with phosphodiesterase 5-inhibitors and intracavernous drug injection. Sacral neuromodulation, transcutaneous electrical nerve stimulation, and intraurethral suppositories have been poorly studied, but preliminary studies did not show convincing results.

CONCLUSION

The best treatment options for erectile dysfunction in spinal cord injury patients emerged to be phosphodiesterase 5-inhibitors and intracavernous drug injection. The choice of erectile dysfunction treatment should be based on several aspects, including residual erectile function, spinal cord injury location, and patients' comorbidities. Future studies assessing the applicability of less well-studied treatments, as well as evaluating innovative options, are needed in this specific population.

Safety and Efficacy of Intracavernosal Injections of AbobotulinumtoxinA (Dysport®) as Add on Therapy to Phosphosdiesterase Type 5 Inhibitors or Prostaglandin E1 for Erectile Dysfunction-Case Studies

Erectile dysfunction (ED) is a highly prevalent condition with a variety of possible risk factors and/or etiologies. Despite significant advances regarding ED pharmacological management, there are still insufficient responders to existing pharmacological treatments e.g., approximately 30% of patients are insufficient responders to phosphodiesterase type 5 inhibitors (PDE5-Is). It has been recently proposed that botulinum toxin A intracavernosally (IC) delivered could be effective in these patients. Data from a retrospective uncontrolled single center study of 47 ED patients, consecutively recruited, insufficient responders to existing pharmacological treatments e.g., PDE5-Is or IC PGE1 injections treated with IC abobotulinumtoxinA 250 or 500 U as free combination with their existing treatment have been analyzed. Response rate, according to the International Index of Erectile Function-Erectile Function domain score, 6 weeks following IC abobotulinumtoxinA in combination with prior pharmacological treatment, was 54%. Two patients have reported mild penile pain on injection or during the 3 days following injection. Therapeutic efficacy did not seem to be influenced by the etiologies and/or risk factors for ED. Conversely, the less severe ED, the higher the response rate. Preliminary evidence for the therapeutical potential with acceptable safety of IC abobotulinumtoxinA as add-on therapy for ED not sufficiently responsive to standard therapy should be confirmed in randomized clinical trials.

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.

[Intracavernous injections in the treatment of erectile dysfunction in spinal cord injured patients: experience with 36 patients]

OBJECTIVES

To confirm the efficiency of intracavernous injections in the treatment of erectile dysfunction in spinal cord injured (SCI) patients and to determine the mean necessary dose to obtain functional erection.

MATERIALS

This prospective study concerns 36 spinal cord injured men. None of them had erectile dysfunction before the neurologic impairement. Sixty four intracavernous injections were performed.

METHOD

The first injection was done with the usually recommended starting dose. The injections were then repeated with increasing dosage to archive a rigid erection. The erection was evaluated with Schramek grading. A grade 4 or 5 erection was considered as functional.

RESULTS

Nine tetraplegics and 27 paraplegics were included. Twenty two were grade A in ASIA classification. The mean age was 31 years. Twenty for patients had a level above T10, 11 between T11 and L2, one below L2. Twenty seven patients obtained an erection of grade 4 or 5. Alprostadil was used 51 times, moxisylite nine times and papaverine four times. The average dose necessary to obtain a grade 4 or 5 functional erection adequate for coitus was 12.3 +/- 4.8 microgram with alprostadil and 14 +/- 5.4 mg with moxisylite. No side effects were noted. The nine left patients did not archive satisfying erection during this study. No clinical differences were noted in this population, compared with the 27 other patients.

CONCLUSION

The findings confirm the efficiency of intracavernous injections in the management of erectile dysfunction in SCI. The average doses required to obtain a functional erection was 12.3 (+/- 4.8) microgram with alprostadil and 14 (+/- 5.4) mg with moxisylyte.

Evaluation and nonsurgical management of erectile dysfunction

The addition of oral drugs to the armamentarium of therapies for erectile dysfunction promises to dramatically increase the number of men seeking treatment for this condition. It is important to have a rational approach to the diagnostic evaluation of erectile dysfunction and to tailor the evaluation to each patient's goals for his sexual function. It is important also to offer each patient the full array of therapeutic options for erectile dysfunction. This article reviews the outpatient diagnostic work-up and current treatment possibilities for erectile dysfunction. The article also discusses clinical research experience with new forms or oral and topical therapies now being developed for future treatment of erectile dysfunction.

Moxisylyte: a review of its pharmacodynamic and pharmacokinetic properties, and its therapeutic use in impotence

Moxisylyte is a competitive noradrenaline antagonist, acting preferentially on post-synaptic alpha-1 adrenoceptors. It was introduced more than thirty years ago for the treatment of cerebro-vascular disorders and shown more recently effective in the urological field due to its ability to modulate the urethral pressure. Renewal of interest in this drug has been observed in recent years since the demonstration of the possibilities of vasoactive drugs in evaluation and treatment of erectile dysfunctions. Moxisylyte is a prodrug, rapidly transformed into an active metabolite in plasma (Deacetylmoxisylyte or DAM). Elimination of the active metabolite occurs by N-demethylation, sulpho- and glucuroconjugation. The N-demethylated metabolite is sulphoconjugated only. Urine is the main route of excretion. The metabolites of moxisylyte can be determined in biological fluids by various methods using high-performance liquid chromatography. Their pharmacokinetics is dependent on the route of administration. By the oral route, the concentrations of the active metabolite are low, and the glucuroconide of DAM predominates over the sulphates. After intravenous and intracavernous injection, the active metabolite is proportionally higher, the two sulphates are equivalent and in larger amounts than the glucuronide. In the treatment of impotence, intracavernous injection of moxisylyte at 10, 20 or 30 mg can induce an erection adequate for intercourse in most of the patients. Compared to inducing agents such as papaverine and prostaglandin E1, moxisylyte must be considered as a facilitator of male erection, its interest lying in the low rate of adverse effects, either general or local.

Double-blind multicenter study comparing alprostadil alpha-cyclodextrin with moxisylyte chlorhydrate in patients with chronic erectile dysfunction

PURPOSE

We compared the efficacy and safety of alprostadil alpha-cyclodextrin and moxisylyte chlorhydrate to induce erections adequate for sexual intercourse in a prospective, randomized, parallel double-blind study in patients with erectile dysfunction.

MATERIALS AND METHODS

A total of 156 men with erectile dysfunction due to organic, nonorganic and mixed origin was randomized into 2 parallel treatment groups receiving titrations of an individual optimum dose of alprostadil alpha-cyclodextrin or moxisylyte chlorhydrate. Erectile response was measured by the buckling test. A positive test was associated with axial erection rigidity that did not buckle/deform to 1.0 kg. load. The buckling test was repeated every 10 minutes for up to 60 minutes.

RESULTS

A total of 56 patients (75%) in the alprostadil alpha-cyclodextrin group and 32 patients (40%) in the moxisylyte chlorhydrate group responded with at least 1 positive buckling test during the office period. Investigators assessed erections after alprostadil alpha-cyclodextrin to be adequate for sexual intercourse in 61 patients (81%) compared to 37 patients (46%) after moxisylyte chlorhydrate. All efficacy parameters in office reached statistical significance of p < 0.001 in favor of alprostadil alpha-cyclodextrin. During self-injection therapy at home 58 patients (85%) reported at least 1 rigid erection after alprostadil alpha-cyclodextrin compared to 37 patients (61%) after moxisylyte chlorhydrate. Patient and partner opinion of treatment achieved statistically significantly better scores in the alprostadil alpha-cyclodextrin group compared to the moxisylyte chlorhydrate group.

CONCLUSIONS

Alprostadil alpha-cyclodextrin is significantly more effective than moxisylyte chlorhydrate in producing full penile rigidity in office and at home. Injection related side effects occur with the same frequency but moxisylyte results in more systemic side effects and alprostadil results in more painful and prolonged erections. Patients and partners are significantly more satisfied with alprostadil alpha-cyclodextrin.

High-performance liquid chromatographic determination of the conjugate metabolites of moxisylyte in human plasma and urine

Sensitive and specific high-performance liquid chromatographic methods with fluorescence detection are described for the determination of the metabolites of moxisylyte (4-(2-dimethylaminoethoxy)-5-isopropyl-2-methylphenyl acetate) in human plasma and urine. Deacetylmoxisylyte glucuroconjugate (DAM-G) was hydrolysed enzymatically using 1-glucuronidase and quantified as the difference between the DAM concentrations determined after and before hydrolysis. The two sulphate derivatives (deacetylmoxisylyte sulphoconjugate, DAM-S and monomethyldeacetylmoxisylyte sulphoconjugate, MDAM-S), were analysed without prior hydrolysis. Their extraction from plasma and urine, as well as that of DAM from plasma, involved the use of C18 cartridges adapted on a Benchmate workstation. DAM in urine was quantified after liquid-liquid extraction. The two methods were validated for specificity, linearity, intra- and inter-day precision and accuracy. Precision was generally < or = 15% and accuracy < or = 12%. In plasma, the limits of quantification were 2.5 ng/ml for DAM and 2.8 ng/ml for the two sulphates, in urine, they were 40 ng/ml for DAM and 200 ng/ml for the sulphates. These methods were used for pharmacokinetic studies in healthy subjects.

Pharmacokinetics of moxisylyte in healthy volunteers after intravenous infusion and intracavernous administration with and without a penile tourniquet

The concentration-time profiles of metabolites of moxisylyte (or thymoxamine), an alpha-blocking agent, were investigated in 18 healthy volunteers after intravenous (i.v.) and intracavernous (i.c.) administrations with and without a tourniquet. Four metabolites, unconjugated desacetylmoxisylyte (DAM), DAM glucuronide, and DAM and monodesmethylated DAM (MDAM) sulfates, were found in plasma and urine. For all metabolites, tmax was significantly increased after i.c. administrations and Cmax was significantly decreased. Maximum plasma level of unconjugated DAM was lower after i.c. administration with (1.81-fold) and without (1.26-fold) a tourniquet than after i.v. administration (43.6 +/- 19.6 ng/ml). The elimination half-life of each metabolite showed no change between the three treatments. The difference of 19 min between the mean residence times of unconjugated DAM after i.c. administration with and without a tourniquet may be compared with the difference between the mean duration of the intumescence, that is, 19 min (73 and 54 min with and without a tourniquet, respectively). Total percentages of metabolites recovered in urine were 66.2 +/- 20.9, 61.4 +/- 12.2, and 58.7 +/- 9.1% after i.v. and i.c. administrations with and without a tourniquet, respectively. In conclusion, tourniquet placed before i.c. administration increased the mean residence time of unconjugated DAM of approximately 25% and seemed to increase the efficacy of the drug in healthy volunteers.

Clinical approach to erectile dysfunction in spinal cord injured men. A review of clinical and experimental data

Despite the many developments in the area of sexual dysfunction, rehabilitation settings seldom investigate the remaining sexual function following spinal cord injury, or offer differential diagnoses of sexual dysfunction in spinal cord injured men. This article attempts to show how sexual rehabilitation should begin with a thorough assessment of the sexual function of paraplegic and tetraplegic men. Assessment includes a basic neurological examination of the perineal area and an extended clinical interview on sexual function and visceral function. The interpretation of patient evaluation is discussed in terms of a classification system adapted to sexual purposes and in terms of the differential diagnoses between sexual dysfunctions of organic, and those of predominantly psychogenic origin in the spinal cord injured patient. The organic or psychogenic contribution is discussed in terms of sophisticated procedures, where assessment of nocturnal penile tumescence (NPT) is critically evaluated and where alternatives such as urodynamic findings and skin potentials are discussed. Treatment strategies, such as intracavernous injections and cognitive-behavioural strategies adapted to different lesion types, are discussed.

PSA and clinical problems relating to prostate cancer

The PSA is the most important tumoral marker for prostate cancer. Not all Authors agree that it plays an important role in screening and diagnosis, classification and prognosis; they agree, instead, about its monitoring the response to therapy. Two personal experiences are presented: in one the PSA values are compared with the prostatic biopsies in 100 patients with suspect rectal exploration; in the other the PSA value, taken at the moment of diagnosis, is compared with the result of the radionuclide bone scan in 43 patients with prostate cancer.