An open-label, uncontrolled dose-optimization study of sublingual apomorphine in erectile dysfunction

Spontaneous Ejaculation: A Focused Review for the Clinicians

INTRODUCTION

The process of ejaculation has important meanings not only for its association with orgasm but also for the timing to ejaculate in the context of sexual activity. Spontaneous (involuntary) ejaculation (SE) without any sexual stimulation is a distressing symptom. Our understanding of SE is limited. Unfortunately, many physicians are not aware of these cases.

OBJECTIVES

The objective of this study is to describe the etiopathogenesis, clinical features, diagnosis, and treatment options for SE.

METHODS

We searched the literature for publications on "SE," "spontaneous emission" or "involuntary ejaculation," and factors influencing SE in the PUBMED/MEDLINE, Scopus, Cochrane Library, EMBASE, PsycINFO, ProQuest, Academic Search Complete database, Google Scholar, and CINAHL databases from inception to August 2020.

RESULTS

The literature search yielded 36 relevant publications reporting on 43 patients with SE. Attempts to explain the cause of pathologic SE have included 4 etiological groups (spinal cord lesions, psychological causes, rabies, and drug-induced). The underlying mechanisms responsible for induction of SE may include increased adrenergic activity, overactivity in dopaminergic system, decreased serotonergic activity, damage of descending inhibitory pathway, or penile hyperexcitability. SE may occur in the absence of an identifiable trigger or may be triggered by non-sexual circumstances (micturition, defecation, glans touch, anxiety, panic attack, or school examinations). Treatment options include psychoanalytic treatment, paroxetine, citalopram, sertraline, silodosin, and anxiolytics. In drug-induced SE, dose reduction and drug withdrawal with or without switching to another drug may relief SE.

CONCLUSIONS

SE is one of the least reported ejaculatory dysfunction. The key feature shared in common by these men is SE without any sexual thoughts or fantasies, may be triggered by non-sexual contexts, rarely associated with orgasm or erection. Treatment by psychoanalytic treatment and pharmacotherapy may be helpful. Further research might explore the definite underlying mechanisms. Abdel-Hamid IA, Ali OI. Spontaneous Ejaculation: A Focused Review for the Clinicians. Sex Med Rev 2021;9:406-422.

Methylphenidate-induced erections in a prepubertal child

Methylphenidate is a medication used routinely in the management of attention deficit hyperactivity disorder. We report a case of a prepubertal child who developed unwanted erections after commencing a response-adjusted dosing regimen of sustained release methylphenidate. Despite priapism being a rare adverse reaction associated with methylphenidate, physicians and parents need to be aware as it can have significant long-term complications.

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.

A comparative review of apomorphine formulations for erectile dysfunction : recommendations for use in the elderly

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men worldwide. First-line oral therapy for ED includes the use of phosphodiesterase type 5 inhibitors (sildenafil, tadalafil and vardenafil) and sublingual apomorphine. Apomorphine is a dopamine D(1) and D(2) receptor agonist that has been approved for marketing in Europe. Different apomorphine formulations have been tested, such as sublingual, subcutaneous and intranasal. However, the sublingual formulation has shown the best results in terms of efficacy, safety and tolerability, especially the 2mg and 3mg doses. Although clinical studies of the efficacy and tolerability of apomorphine sublingual (SL) have included older patients, who are more likely to have ED, no study has specifically assessed the efficacy and tolerability of different doses of apomorphine SL in aging men. Therefore, a MEDLINE search was conducted from January 1987 to November 2005 to identify studies of the efficacy, safety (in particular cardiovascular safety) and tolerability of different apomorphine formulations and doses as treatments for ED in the subcohort of aging men. On the basis of the most recent peer-reviewed publications, the first part of this article critically evaluates data regarding the epidemiology of ED in the aging population. The second part of the article focuses on the mechanism of action and pharmacokinetics of apomorphine both in the general and the elderly population. Finally, a critical analysis of the efficacy and safety of different apomorphine formulations and doses for the treatment of ED is reported. Apomorphine represents a first-line oral treatment for ED. Available formulations include only sublingual administration. Few studies have assessed the efficacy and safety of apomorphine in the elderly population. However, in clinical practice, older patients with multiple vascular risk factors and systematic vascular damage show poor overall response to apomorphine SL for the treatment of ED.

Examination of the safety and use of apomorphine prescribed in general practice in England as a treatment for erectile dysfunction

OBJECTIVE

To examine the safety and use of apomorphine as prescribed in general medical practice in England as a treatment for erectile dysfunction (ED).

PATIENTS AND METHODS

Apomorphine hydrochloride (marketed as Uprima, Abbott Laboratories Ltd, UK) is licensed in the UK as a sublingual therapy for ED. It is the first treatment for ED with a central mode of action. This postmarketing observational cohort study was conducted using prescription-event monitoring (PEM) methods. Exposure information was obtained from dispensed prescription data for patients first prescribed apomorphine between October 2001 and December 2002. Outcome data were derived from Green-Form questionnaires posted to prescribing physicians > or = 6 months after the date of the first apomorphine prescription for each patient. The study cohort comprised 11 185 patients, 99.3% (11,111) of whom were men, with a median (interquartile range) age of 61 (54-68) years.

RESULTS

The most frequently reported prescribing indication was ED and the most frequently reported reason for stopping apomorphine was that it was 'not effective'. In addition, the percentage of patients for whom apomorphine was reported to have been effective was relatively low. Headache was the most commonly reported adverse drug reaction, and the most frequently reported clinical condition occurring in the first month of observation. A small number of events (24) were reported that were not listed in the current Summary of Product Characteristics (SPC) and were considered by the prescribing general practitioner (GP) to be associated with apomorphine use.

CONCLUSION

The proportion of patients for whom apomorphine was reported to be effective was low. Also, 'not effective' was the most frequently reported event and a high percentage of patients stopped apomorphine because it was 'not effective'. The most frequently reported clinical adverse events (headache and nausea) were those listed in the SPC. A small number of reports for unlabelled events were thought by prescribers to be related to apomorphine use. The confounding factors of patient age and coexisting disease should be considered when assessing data from this study.

Erectile Dysfunction Following Radical Retropubic Prostatectomy

Radical prostatectomy has been the time-honoured and standard treatment option for prostate cancer. Erectile dysfunction (ED) is one of the common quality-of-life issues following radical prostatectomy. The recovery of potency following radical prostatectomy varies from 16% to 86%. Although major modifications in surgical technique appear to be promising, the reported ED rates are still high. The time period required for the recovery of erectile function after surgery varies from 6 to 24 months. During this period of neuropraxia lack of natural erections produces cavernosal hypoxia. This cavernosal hypoxia has been implicated as one of the most important factors in the pathophysiology of ED. Cavernosal hypoxia predisposes to cavernosal fibrosis, ultimately producing venous leak and long-term ED. Interruption of this cascade of events has been the major challenge for physicians. Physicians have several options available for the treatment of ED. However, oral treatment options have quickly become established as first-line treatment options. Sildenafil has been most extensively studied in the radical prostatectomy population. In patients who do not respond to oral therapy alone, standard treatment options (intracavernosal injections, vacuum constriction devices and intraurethral alprostadil) are useful. Use of penile prostheses is one of the oldest treatment options available for the treatment of ED but is used only as a last resort. Initial attempts to promote the earlier recovery of erectile function appear to be promising. However, further confirmatory studies are essential. The roles of gene transfer and growth factors are still in experimental stages. In this review we discuss the epidemiology, pathophysiology and treatment options available for ED following radical prostatectomy.

Central Nervous System Agents in the Treatment of Erectile Dysfunction

In the last two decades, a better understanding of the mechanisms governing erectile function and the pathophysiologies underlying erectile dysfunction (ED) have led re-searchers to investigate novel treatment concepts. Selective type-5 phosphodiesterase inhibitors are recommended as first-line therapy because of their high efficacy, but 30% to 40% of patients who have ED do not respond adequately to these agents and require alternative methods. The central nervous system plays a fundamental role in sexual behavior. Animal models have advanced our understanding of the neuroanatomic and neuropharmacologic basis of centrally induced penile erections. Clinical research with apomorphine has demonstrated efficacy in men who have a range of ED. Recent interest has focused on other centrally acting agents for ED treatment, including the melanocortin receptor agonists.

The etiology of erectile dysfunction and contributing factors in different age groups in Turkey

BACKGROUND

The aim of the present study was to determine the pathophysiological factors which cause erectile dysfunction (ED), as well as the risk factors in different age groups in Turkey.

METHODS

A total of 948 patients with ED who were admitted to three andrology clinics were evaluated in terms of etiological factors. They underwent a multidisciplinary diagnostic evaluation. Erectile dysfunction was classified as primarily organic, primarily psychogenic, mixed or unknown in etiology.

RESULTS

Psychogenic ED was diagnosed in 65.4% of the patients and organic ED was diagnosed in 34.6% of patients overall. In patients under 40 years, the rate of psychogenic ED was 83% and the rate of organic ED was 17%, but in the patients over 40 years, the rate of psychogenic ED was 40.7% and the rate of organic ED was 59.3%. The causes of organic ED were identified as arteriogenic ED, 40.5%; cavernosal factor (venogenic) ED, 10%; neurogenic ED, 12.5%; endocrinologic ED, 1.8%; mixed type ED, 11.8%; and drug induced ED, 4.5%.

CONCLUSION

Our data represent a higher ratio of ED in patients under 40, which are mostly psychogenic, This finding potentially results from local social and cultural differences.

Clinical efficacy of Apomorphine SL in erectile dysfunction of diabetic men

Although subgroup analyses from large randomised premarketing studies have shown that Apomorphine SL enhances the percentage of erections firm enough for sexual intercourse in diabetic men, the clinical role of the drug in this patient population remains to be elucidated. The aim of the present study was to assess the efficacy of Apomorphine SL in diabetic males with erectile dysfunction (ED) and to identify factors predicting those who may benefit from the treatment. A total of 130 diabetic patients were randomised to receive either four tablets of 3 mg Apomorphine or a matching placebo. Assessments of efficacy comprised the erectile function (EF) domain of the International Index of Erectile Function (IIEF) and the one-item global efficacy question (GEQ). Patients with both a positive response to the GEQ and an improvement of at least 5 points in the EF domain of the IIEF were considered responders and subanalysed by several parameters indicative of the severity of both ED and diabetes. Response rate was 17% after placebo and 22% after Apomorphine SL. The EF domain of the IIEF and both questions 3 and 4 scores did not significantly improve in either of the two arms over the baseline. A younger age and a lower Hb1Ac were significantly linked to the status of responder in the Apomorphine arm. Apomorphine SL failed to show a statistically significant benefit over a placebo, but 22% of patients had a clinically significant erectile response. These figures seem to suggest that the drug has a limited use for ED diabetic patients.

Erectile dysfunction: etiology, evaluation, and treatment options

The evaluation and treatment of male sexual dysfunction has evolved into a more extensive evaluation. This new evaluation should now include evaluation of hypogonadism, ejaculatory function, lower urinary tract symptoms, and depression. The evaluation may be readily accomplished with the use of questionnaires. The management of these entities is discussed, including the novel phosphodiesterase-5 for male erectile dysfunction. Inclusion of the partner in the evaluation and management scheme will provide added benefit and may produce a better outcome.

Clinical Experience With Apomorphine Hydrochloride: The First 107 Patients

PURPOSE

We assessed the efficacy and safety of apomorphine hydrochloride in patients with erectile dysfunction.

MATERIALS AND METHODS

A total of 107 patients who had consultations because of erectile dysfunction between July and November 2001 were assessed. The sample was randomly selected.

RESULTS

Response to apomorphine hydrochloride was assessed in 107 patients complaining of erectile dysfunction, randomly selected at the office. With the 2 mg initial dose the response amounted to 23.5%, with 3 mg it amounted to 28.5% and the global response to the drug amounted to 26.1%. Positive response was obtained in 18.5% of those in whom the dose was increased from 2 to 3 mg. Obtaining an erection with enough rigidity to enable coitus satisfactory for the patient was accepted as a positive response. According to the clinical presentation of the erectile dysfunction, the highest efficacy was found in those cases with early detumescence, and the lowest one in those cases with complete affection. The overall incidence of adverse effects was 8.4%, with nausea being the most frequently reported.

CONCLUSIONS

Apomorphine hydrochloride is the first central action erection inducing drug. Its use is encouraged by high tolerability, low rate of adverse effects and virtually nonexistent interaction with other drugs usually administered to patients with erectile dysfunction.

Systemic apomorphine alters HPA axis responses to interleukin-1 beta administration but not sound stress

Apomorphine is a dopamine receptor agonist that was recently licensed for the treatment of erectile dysfunction. However, although sexual activity can be stressful, there has been little investigation into whether treatments for erectile dysfunction affect stress responses. We have examined whether a single dose of apomorphine, sufficient to produce penile erections (50 microg/kg, i.a.), can alter basal or stress-induced plasma ACTH levels, or activity of central pathways thought to control the hypothalamic-pituitary-adrenal axis in rats. An immune challenge (interleukin-1 beta, 1 microg/kg, i.a.) was used as a physical stressor while sound stress (100 dB white noise, 30 min) was used as a psychological stressor. Intravascular administration of apomorphine had no effect on basal ACTH levels but did substantially increase the number of Fos-positive amygdala and nucleus tractus solitarius catecholamine cells. Administration of apomorphine prior to immune challenge augmented the normal ACTH response to this stressor at 90 min and there was a corresponding increase in the number of Fos-positive paraventricular nucleus corticotropin-releasing factor cells, paraventricular nucleus oxytocin cells and nucleus tractus solitarius catecholamine cells. However, apomorphine treatment did not alter ACTH or Fos responses to sound stress. These data suggest that erection-inducing levels of apomorphine interfere with hypothalamic-pituitary-adrenal axis inhibitory feedback mechanisms in response to a physical stressor, but have no effect on the response to a psychological stressor. Consequently, it is likely that apomorphine acts on a hypothalamic-pituitary-adrenal axis control pathway that is unique to physical stressors. A candidate for this site of action is the nucleus tractus solitarius catecholamine cell population and, in particular, A2 noradrenergic neurons.

Beta-phenylethylamines and the isoquinoline alkaloids

This review covers beta-phenylethylamines and isoquinoline alkaloids and compounds derived from them, including further products of oxidation, condensation with formaldehyde and rearrangement, some of which do not contain an isoquinoline system, together with naphthylisoquinoline alkaloids, which have a different biogenetic origin. The occurrence of the alkaloids, with the structures of new bases, together with their reactions, syntheses and biological activities are reported. The literature from July 2001 to June 2002 is reviewed, with 581 references cited.

Tolerability and safety of apomorphine SL (Ixense (TM) )

Apomorphine SL (Ixense (TM) ) (apo SL) is a dopamine receptor agonist that can enhance sexual function in patients with erectile dysfunction (ED). For a patient, the ability to achieve a physiological erection, tolerability, efficacy and the speed of onset of the therapy are of considerable importance when considering ED treatment. Recent studies have focused on determining the patient's tolerability to apo SL as a therapy for ED. In addition, the cardiovascular profile of those patients that would be likely to receive apo SL in the clinic has been assessed. These studies have shown that apo SL is safe and effective in the treatment of ED and offers a new therapeutic option for the first-line treatment of patients with different concomitant diseases including cardiovascular disease and diabetes. The most frequently reported adverse events were nausea and dizziness, but no major adverse events have been noted in any of the clinical trials.

Evaluating dose regimens of apomorphine, an open-label study

The aim of the study was to investigate the safety and efficacy of apomorphine SL (apo SL) 2 and 3 mg, using a dose-optimisation regime in 110 Asian men with erectile dysfunction (ED) during a 10-week open-label study. Based on daily diaries kept by each patient, 63% showed an improvement in their sexual life. Patient responses to the International Index for Erection Function 15 questionnaires showed that there was an improvement in erectile function from baseline score after treatment with apo SL (from 15.9 to 20.4), and intercourse satisfaction (from 7.7 to 9.9), as well as slight improvements in orgasmic function (from 6.8 to 7.5) and total satisfaction (from 41.9 to 50.8). There was no marked improvement seen in sexual desire. In conclusion, apo SL is safe and efficacious in the treatment of ED in this patient population, irrespective of underlying diseases and concomitant medications.

Dopamine D1 receptor agonists induce penile erections in rats

The dopamine receptor agonist apomorphine has been recently introduced in the treatment of erectile dysfunction. While it is well established that dopamine D2-like receptors play a crucial role in this effect, conflicting result are reported in the literature as for the role of dopamine D1-like receptors. The aim of this study was to determine the effect of systemic administration of dopamine D1-like receptor agonists on penile erection in rats. Male Wistar rats were treated with three different, and not structurally related, dopamine D1-like receptor agonists: the partial agonists SKF38393 ((+) 2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine) and CY 208-243 ((-)-4,6,6a,7,8,12b-exahydro-7-methylindole [4,3-ab]fenantridine), and the full agonist A 77636 ((-)-(1R,3S)-3-Adamantyl-1-(aminomethyl)-3,4-dihydro-5,6-dihydroxy-1H-2-benzopyran hydrochloride). All three compounds dose-dependently increased the number of penile erections, with the full agonist A77636 showing a more pronounced effect with respect to the other two. Moreover, the dopamine D1-like receptor antagonist SCH 23390 ((R)-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine) dose-dependently antagonised A77636 effect. These results show that systemic administration of dopamine D1-like receptor agonists induce penile erection in rats. This observation suggests that dopamine D1-like receptor agonists might be considered as a possible alternative to apomorphine in the treatment of erectile dysfunction, thus avoiding the typical side effects related to the stimulation of dopamine D2-like receptors such as nausea.

A European multicentre study to evaluate the tolerability of apomorphine sublingual administered in a forced dose-escalation regimen in patients with erectile dysfunction

OBJECTIVE

To determine the risk-benefit ratio of a forced dose-escalation regimen (2 to 3 to 4 mg) in a European clinical study evaluating apomorphine sublingual (SL) in treating erectile dysfunction (ED), by evaluating the overall tolerability and efficacy of the regimen compared with placebo in patients with ED, and evaluating efficacy by assessing the proportion of successful attempts resulting in sexual intercourse.

PATIENTS AND METHODS

This randomized, double-blind, two-arm, parallel-group study was conducted in 507 patients enrolled at 34 European sites. After a 1-2 week screening period, patients were treated for 8 weeks with either placebo or apomorphine SL administered as a forced dose-escalation regimen. Heterosexual men (aged 18-70 years) were eligible for participation in the study if they were in stable health, a stable relationship of > or = 6 months duration, had a history of erectile inability, and were diagnosed with ED (successful in fewer than half of attempts to attain and maintain an erection firm enough for intercourse during the 30 days before screening). Patients provided information (recorded on diary cards and reviewed at each study visit) about the frequency and success in achieving erections and of sexual intercourse attempts during both the screening and treatment periods. The dosing regimen required patients to take one tablet of apomorphine SL (2 mg for 2 weeks, then 3 mg for 2 weeks and finally 4 mg for the remaining 4 weeks) or placebo 15-25 min before intercourse, and intercourse was to be attempted at least twice a week. Safety data were collected throughout the 8-week study period, and included recording adverse events, vital signs and changes in laboratory test values for standard haematology and biochemistry variables. The primary efficacy variable was the proportion of successful attempts, defined as an erection rigid enough for sexual intercourse, occurring after dosing (successful intercourse rate). The proportion of erections achieved was a secondary efficacy variable.

RESULTS

Of the 507 patients, 254 received apomorphine SL and 253 received placebo; 87% of patients in both groups completed the 8-week treatment period. Of the patients receiving apomorphine SL, 24% had hypertension, 11% had coronary artery disease, 10% had diabetes, and 5.5% had benign prostatic hypertrophy; 62.6% of treated patients received concomitant medications for these maladies. The treatment groups were balanced for demographic and baseline variables, including comorbidity factors. Treatment-emergent adverse events, reported by > 5% of patients in the treated group, were nausea (9.8%), dizziness (7.1%) and headache (6.7%), compared with 0.4%, 2.4% and 4.0%, respectively, in the placebo group. Sixty-six patients withdrew from the study, 16 because of study drug-related adverse events (12 from the apomorphine and four from the placebo group). Six patients (three in each group) reported a total of nine serious treatment-emergent adverse events, all of which resolved by the end of the study. In the intention-to-treat population, the proportion of successful attempts at sexual intercourse and of erections were statistically greater in the apomorphine than in the placebo group (P = 0.001 and 0.021, respectively); analysis of the per-protocol population results confirmed this significant difference.

CONCLUSION

This European study supports the safety and tolerability of apomorphine SL despite the forced escalation to a 4-mg dose (exceeding the approved 2-3 mg dose). Adverse effects were not treatment-limiting. These results further support the clinically significant efficacy of apomorphine SL for treating ED at all doses used. The risk/benefit ratio supports apomorphine SL as a safe and effective alternative in managing ED.

Sequential administration enhances the effect of apomorphine SL in men with erectile dysfunction

The response to Uprima (apomorphine sublingual, (apo SL)) has been well documented in conventional clinical trials. Apo SL produces a predictable, consistent and durable response across a wide variety of patients. The positive reinforcement of a successful outcome should further support clinical benefit. Apo SL with its rapid onset affords a greater opportunity for spontaneity, which can be an important factor in influencing patient choice. It is recognised that patient counselling and the setting of realistic expectations are vital to a successful outcome. The impact of persisting with sequential treatment on outcome has been calculated from the clinical data. While apo SL is effective de novo in 50% of single doses, additional benefit is observed with repeat dosing. Full benefit may not be achieved until four or more treatments have been taken in an optimal setting. The data also confirm that 3 mg has superior activity. Patients should therefore be encouraged to try a minimum of 4 doses at 3 mg.