Double-blind, crossover comparison of 3 mg apomorphine SL with placebo and with 4 mg apomorphine SL in male erectile dysfunction

Apomorphine for the Treatment of Erectile Dysfunction: Systematic Review and Meta-Analysis

Sublingual apomorphine could be an option in patients with erectile dysfunction who cannot take phosphodiesterase type 5 inhibitors (e.g., using nitrates). We have completed a systematic review to evaluate the effects of sublingual apomorphine comparing with placebo for treating erectile dysfunction. The evidence searching process finished on 9 January 2019. We included nine randomized controlled trials (RCTs). Treatment length varied from 4 to 8 weeks and doses ranged from 2 to 6 mg. The percent of successful sexual intercourse attempts per ingested dose of apomorphine was evaluated in eight studies. All the studies found that apomorphine was better than placebo (6-27% more successful intercourse attempts than with placebo), but differences were not statistically significant in one study done in patients previously treated with radical prostatectomy. Regarding erectile function scores, three studies reported higher improvement on the erectile function scores for apomorphine. Differences with placebo were not clinically relevant in another two studies, one in which only diabetic patients were included and one in which only patients with radical prostatectomy were involved. Discontinuation of treatment due to adverse events was higher for apomorphine, particularly for higher doses. Available evidence suggests that sublingual apomorphine is more effective than placebo, except for patients previously treated with radical prostatectomy, and is generally well tolerated at doses of 2 or 3 mg. Nowadays, sublingual apomorphine is the only licensed oral drug for erectile dysfunction not absolutely contraindicated with nitrates use, and more RCTs should be performed to evaluate its effects and safety for treating ED.

Treatment of autonomic dysfunction in Parkinson disease and other synucleinopathies

Dysfunction of the autonomic nervous system afflicts most patients with Parkinson disease and other synucleinopathies such as dementia with Lewy bodies, multiple system atrophy, and pure autonomic failure, reducing quality of life and increasing mortality. For example, gastrointestinal dysfunction can lead to impaired drug pharmacodynamics causing a worsening in motor symptoms, and neurogenic orthostatic hypotension can cause syncope, falls, and fractures. When recognized, autonomic problems can be treated, sometimes successfully. Discontinuation of potentially causative/aggravating drugs, patient education, and nonpharmacological approaches are useful and should be tried first. Pathophysiology-based pharmacological treatments that have shown efficacy in controlled trials of patients with synucleinopathies have been approved in many countries and are key to an effective management. Here, we review the treatment of autonomic dysfunction in patients with Parkinson disease and other synucleinopathies, summarize the nonpharmacological and current pharmacological therapeutic strategies including recently approved drugs, and provide practical advice and management algorithms for clinicians, with focus on neurogenic orthostatic hypotension, supine hypertension, dysphagia, sialorrhea, gastroparesis, constipation, neurogenic overactive bladder, underactive bladder, and sexual dysfunction. © 2018 International Parkinson and Movement Disorder Society.

Dopaminergic Therapies for Non-motor Symptoms in Parkinson's Disease

Apart from the typical motor symptoms, Parkinson's disease is characterized by a wide range of different non-motor symptoms, which are highly prevalent in all stages of the disease and have an incisive influence on quality of life. Moreover, their treatment continues to be challenging. In this review, we critically summarize the evidence for the impact of dopaminergic therapies on non-motor symptoms in Parkinson's disease. We performed a PubMed search to identify relevant clinical studies that investigated the response of non-motor symptoms to dopaminergic therapy. In the domain of neuropsychiatric disturbances, there is increasing evidence that dopamine agonists can ameliorate depression or anxiety. Other neuropsychiatric symptoms such as psychosis or impulse control disorders can also be worsened or even be induced by dopaminergic agents. For the treatment of sleep disturbances, it is essential to identify different subtypes of sleep pathologies. While there is for example profound evidence for the effectiveness of dopaminergic medication for the treatment of restless legs syndrome and sleep fragmentation, evidence for an improvement of rapid eye movement sleep behavior disorder is lacking. With regard to the broad spectrum of autonomic disturbances, response to dopaminergic treatment seems to differ largely, with on the one hand, some evidence for an improvement of sexual function or sweating with dopaminergic treatment, while on the other hand, constipation can be worsened. Finally, the analysis of sensory deficits reveals that some forms of pain, in particular fluctuation-dependent dystonic pain, can be well addressed by adapting the dopaminergic therapy, while no effect has been seen so far for hyposmia or visual deficits. Moreover, the occurrence of non-motor fluctuations is gaining increased attention, as they can be specifically addressed by a more continuous dopaminergic intake. Taken together, there is evidence of a good response of some (but not all) non-motor symptoms to dopaminergic therapy, which must be individually adapted to the special spectrum of symptoms.

Review: Modern treatment of erectile dysfunction

Within the last two decades, major advances have been made in the development of effective treatments for erectile dysfunction. Oral therapy is now established as the mainstay of treatment and new treatments continue to emerge following the launch of sildenafil in 1998. We review here modern treatment strategies for erectile dysfunction.

Treatment strategies for diabetic patients suffering from erectile dysfunction: an update

INTRODUCTION

Erectile dysfunction (ED) is one of the most common complications of diabetes. The complex pathophysiology of this disease makes it difficult to create clinical treatments tailored specifically for diabetic patients.

AREAS COVERED

This article will provide an update of both medical and surgical treatment approaches for diabetic ED, as well as discuss established treatments that are the cornerstone of this field.

EXPERT OPINION

Currently, PDE type 5 inhibitors represent the first-line treatment for all patients with ED. In the interim since this article's first publication several new PDE5 inhibitors have come to market. Several others that were previously on the market are now available for daily dosing. Analysis of both testosterone level and hemoglobin A1c is an essential part of treatment. Intracavernosal injections and vacuum constriction devices remain safe, and are highly effective treatment options. The implantable penile prosthesis remains a safe, and definitive treatment modality for those patients with refractory ED. Over the coming years as the understanding of the underlying causes of diabetic ED continues, the development of new, noninvasive, but effective medical treatments will lead to even more options for the treatment of this difficult disease.

Management of motor and non-motor symptoms in Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder that affects approximately 1 % of people over the age of 60 years. Accurate diagnosis and individualized assessment of the risks and benefits of available antiparkinsonian medications as well as specific clinical features and the phase of disease should guide treatment for patients with PD. Levodopa still remains the gold standard for the treatment of motor symptoms of PD but dopamine agonists (DAs), catechol-O-methyltransferase (COMT) inhibitors and monoamine oxidase B (MAO-B) inhibitors have also been developed to provide more continuous oral delivery of dopaminergic stimulation in order to improve motor outcomes and decrease the risk of levodopa-induced motor complications. Deep-brain stimulation as well as other invasive therapies can be used for the treatment of drug-refractory levodopa-induced motor complications. Despite all of the therapeutic advances achieved within the last 20 years, PD continues to be a progressive disorder leading to severe disability caused by motor and non-motor symptoms. To date, neuroprotective interventions able to modify PD progression are not available. This review focuses on medical and invasive treatment strategies for early and advanced stages of PD as well as on the treatment of PD non-motor symptoms such as mood and behavioural disorders, cognitive and autonomic dysfunction, and sleep disorders, which can antedate PD motor symptoms for years.

Apomorphine is a bimodal modulator of TRPA1 channels

Apomorphine is a non-narcotic derivative of morphine, which acts as a dopamine agonist and is clinically used to treat "off-states" in patients suffering from Parkinson's disease. Adverse effects of apomorphine treatment include severe emesis and nausea, and ulceration and pain at the injection site. We wanted to test whether sensory transient receptor potential (TRP) channels are a molecular target for apomorphine. Here, we show that rTRPV1, rTRPV2, rTRPV3, and mTRPV4, as well as hTRPM8, and rTRPM3, which are expressed in dorsal root ganglion neurons, are insensitive toward apomorphine treatment. This also applied to the cellular redox sensor hTRPM2. On the contrary, human TRPA1 could be concentration-dependently modulated by apomorphine. Whereas the addition of apomorphine in the low micromolar range produced an irreversible activation of the channel, application of higher concentrations caused a reversible voltage-dependent inhibition of heterologously expressed TRPA1 channels, resulting from a reduction of single-channel open times. In addition, we provide evidence that apomorphine also acts on endogenous TRPA1 in cultured dorsal root ganglion neurons from rats and in the enterochromaffin model cell line QGP-1, from which serotonin is released upon activation of TRPA1. Our study shows that human TRPA1 is a target for apomorphine, suggesting that an activation of TRPA1 might contribute to adverse side effects such as nausea and painful injections, which can occur during treatment with apomorphine.

Nonmotor manifestations in Parkinson disease

BACKGROUND

Although the diagnosis of Parkinson disease (PD) still relies mainly on the appearance of its classical motor features of resting tremor, rigidity, bradykinesia, and postural instability, nonmotor manifestations in PD are now recognized as an integral component of this multisystem disorder.

REVIEW SUMMARY

Nonmotor complications in PD occur commonly. The current understanding of cognitive dysfunction; neuropsychiatric manifestations including psychosis, impulsive control, and compulsive disorders, depression, anxiety and apathy; autonomic complications such as hypotension, erectile dysfunction, and urinary complications; sleep disorders and other nonmotor manifestations are summarized in this review.

CONCLUSION

Nonmotor complications often carry a greater impact than motor features in PD. Therefore, heightened awareness and proper recognition of these features are critical in improving a Parkinson patient's quality of life.

Nonmotor disorders and their correlation with dopamine: can they be treated by currently available methods?

Many of the nonmotor symptoms in Parkinson disease have a dopaminergic basis, whether the result of dopaminergic degeneration or as a result of dopaminergic treatment. In the latter case, the symptoms may be genuine side effects of drugs (hypotension, pathologic gambling, etc.) or they may be secondary either to the pathoplastic effect they have on the natural course of the disease (nonmotor fluctuations) or to the lack of dopamine (apathy, depression, dopamine withdrawal syndrome, etc.). In all these cases, dopaminergic treatment can be helpful. However, many other nonmotor (and motor) symptoms will have no correlation with dopamine; therefore, they require different treatments, very often with little efficacy, as in apathy or cognitive decline.

Can the flow of medicines be improved? Fundamental pharmacokinetic and pharmacological principles toward improving Phase II survival

In an effort to uncover systematic learnings that can be applied to improve compound survival, an analysis was performed on data from Phase II decisions for 44 programs at Pfizer. It was found that not only were the majority of failures caused by lack of efficacy but also that, in a large number of cases (43%), it was not possible to conclude whether the mechanism had been tested adequately. A key finding was that an integrated understanding of the fundamental pharmacokinetic/pharmacodynamic principles of exposure at the site of action, target binding and expression of functional pharmacological activity (termed together as the 'three Pillars of survival') all determine the likelihood of candidate survival in Phase II trials and improve the chance of progression to Phase III.

Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction

Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.

Restless legs syndrome and erectile dysfunction

STUDY OBJECTIVES

Dopaminergic hypofunction in the central nervous system may contribute to restless legs syndrome (RLS) and erectile dysfunction (ED). We therefore examined whether men with RLS have higher prevalences of ED.

DESIGN

RLS was assessed using a set of standardized questions. Men were considered to have RLS if they met 4 RLS diagnostic criteria recommended by the International RLS Study Group, and had restless legs > or = 5 times/month. Erectile function was assessed by a questionnaire.

SETTING

Community-based.

PARTICIPANTS

23,119 men who participated in the Health Professional Follow-up Study free of diabetes and arthritis.

RESULTS

Multivariate-adjusted odds ratios for ED were 1.16 and 1.78 (95% confidence interval: 1.4, 2.3; P trend < 0.0001) for men with RLS symptoms 5-14 times/mo, and 15+ times/mo, respectively, relative to those without RLS, after adjusting for age, smoking, BMI, antidepressant use, and other covariates. The associations between RLS and ED persisted in subgroup analysis according to age, obesity, and smoking status.

CONCLUSIONS

Men with RLS had a higher likelihood of concurrent ED, and the magnitude of the observed association was increased with a higher frequency of RLS symptoms. These results suggest that ED and RLS share common determinants.

Non-motor symptoms of Parkinson's disease: dopaminergic pathophysiology and treatment

Several studies, including work from the Parkinson's disease (PD) non-motor group and others, have established that the non-motor symptoms of PD are common, occur across all stages of PD, are under-reported, and are a key determinant of quality of life. Research suggests that the non-motor symptoms of the disease are frequently unrecognised by clinicians and remain untreated. Even when identified, there is a common perception that many of these symptoms are untreatable. The role of dopaminergic drugs in treating the various non-motor problems of PD, although clinically recognised, has received little attention. In this Review, we investigate the dopaminergic basis of the range of non-motor symptoms that occur in PD such as depression, apathy, sleep disorders (including rapid-eye movement sleep behaviour disorder), and erectile dysfunction. We discuss the evidence that these symptoms are treatable, at least in part, with various dopaminergic strategies and, where relevant, we also refer to the use of deep-brain stimulation of appropriate targets in the brain. This Review provides a comprehensive overview of the management of this challenging aspect of PD.

Phosphodiesterase type-5 inhibitor and oxidative stress

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men worldwide. Numerous physical and psychological factors are involved in normal erectile function, including neurological, vascular, hormonal and cavernous functions. The current therapy for the condition is pharmacological and psychotherapeutic which regulates the erectile function and amplifies the NO-mediated response. The aim of this work is to test the action of three common phosphodiesterase inhibitors: Tadalafil, Sildenafil Citrate and Vardenafil at 0.05 microM on human monocytes, analyzing the expression of iNOS protein and mRNA by Western blot and rt-PCR, and production of NO by conversion of L-(2,3,4,5)-[3H]Arginine to L-(3H) citrulline. We also tested the efficiency of the antioxidant network by spectrophotometer (SOD, CAT, GPx and Gr), under normal conditions and after stimulation with LPS. The results showed an increase in ROS levels, similar for all the molecules with regard to the antioxidant enzymes. In all cases the treatment determines a response to the limited efficiency, arriving at a situation in which phosphodiesterase inhibitors + LPS clearly show oxidative stress.

British Society for Sexual Medicine guidelines on the management of erectile dysfunction

INTRODUCTION

UK primary care physicians are required to follow authoritative endorsed guidelines as part of their terms of service. The major influence on the management of erectile dysfunction in primary and secondary care between 1999 and 2007 has been Department of Health "guidance on good practice," a non-evidence-based document, essentially defining patients who qualify for government-funded treatment.

AIM

To provide clinically based guidelines relevant to UK primary and secondary healthcare professionals in their daily practice.

METHODS

A multidisciplinary panel of seven UK experts including two primary care physicians from the British Society for Sexual Medicine met for two full day meetings between September 2006 and April 2007, with each member allocated to disease areas related to their specialty. Feedback and approval of all sections between panel members was facilitated by the chairman. Source information was obtained from peer reviewed articles, meetings and presentations. Articles were chosen from electronically searching the Cochrane Library, Medline and Embase for randomized controlled clinical trials and graded according to level of evidence.

RESULTS

Patient-reported sexual activity, satisfaction with sexual activity (Male Sexual Health Questionnaire), and treatment expectations; urologists' subjective assessment of the importance given by their patients to ED; the timing they propose for starting ED treatment.

RESULTS

After the second full day meeting in January 2007, the final version was approved by panel members and made available for healthcare professions by download from http://www.bssm.org and from http://www.eguidelines.co.uk

CONCLUSIONS

A comprehensive evidence-based guideline has been developed that is highly relevant for primary and secondary care professionals enabling them to work within the unique requirements of the UK healthcare system.

Centrally acting mechanisms for the treatment of male sexual dysfunction

The development of pharmacologic therapy for erectile dysfunction (ED) has been possible because of incremental growth in our understanding of the physiology of normal erections and the complex pathophysiology of ED. Although the oral phosphodiesterase type 5 (PDE5) inhibitors have provided safe, effective treatment of ED for some men, a large proportion of men who have ED do not respond to PDE5 inhibitors or become less responsive or less satisfied as the duration of therapy increases. Also, men who are receiving organic nitrates and nitrates, such as amyl nitrate, cannot take PDE5 inhibitors because of nitrate interactions. The current options for treatment beyond PDE5 inhibitors are invasive, unappealing to some patients, and sometimes ineffective. The search for other options by which ED can be treated has branched out and now encompasses centrally acting mechanisms that control erectile function. Drugs available in Europe include apomorphine. This article focuses on the mechanism of centrally acting agents and reviews clinical data on potential new centrally acting drugs for men who have ED.

Design and synthesis of a functionally selective D3 agonist and its in vivo delivery via the intranasal route

This paper reports the synthesis and biological activity of a novel series of aryl-morpholine dopamine receptor agonists. Several compounds show high levels of functional selectivity for the D3 over the D2 dopamine receptor. Compound 26 has >1000-fold functional selectivity and has been successfully progressed in vivo using an intranasal delivery route.

Designing drugs for the treatment of female sexual dysfunction

Dysfunction of female sexual desire, arousal, or orgasm affects approximately 30% of women. Early attempts to treat female sexual dysfunction arose out of programs developed for male erectile dysfunction and have proven largely unsuccessful. A new wave of targets is now being pursued; many of these targets are postulated to modulate central pathways. Classical neurotransmitter systems, such as dopamine and serotonin, as well as the neuropeptide melanocortin, are receiving the most attention. Early clinical data look promising; however, clinical trial methodology in female sexual dysfunction is not well developed and only further testing will determine whether these treatments meet regulatory hurdles and satisfy patient need.

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.

Erectile Dysfunction in Heart Failure Patients

Chronic heart failure (HF) and erectile dysfunction (ED) are 2 highly prevalent disorders that frequently occur concomitantly. Coronary artery disease, HF, and ED share several common risk factors, including diabetes mellitus, hypertension, smoking, and dyslipidemia. Additionally, the distinct physiologic sequelae of HF create unique organic and psychologic factors contributing to ED in this patient population. Standard HF therapy with beta-receptor blockers, digoxin and thiazide diuretics may worsen sexual dysfunction owing to medication side effects. This may, in turn, lead to noncompliance in misguided efforts to retain satisfactory sexual activity, with secondary worsening of cardiac capacity. This review describes the unique aspects of ED in the HF population.

Role of the brain in the control of erection

In contrast to the spinal control of erection, relatively little is known about the brain control. In the present review, we have outlined the role of brain structures involved in penile erection and provided a synopsis on the brain circuit of erection. Findings from both animal and human studies are discussed. Evidence suggests that the most important structures are the frontal lobe, cingulate gyrus, amygdala, thalamus and hypothalamus. Within the brain circuit of erection, the thalamus serves as a gate-controller in which all relevant information is evaluated and further processed to higher and lower centres.

A multidisciplinary approach to assess erectile dysfunction in high-risk cardiovascular patients

Erectile dysfunction (ED) is increasingly considered as one manifestation of systemic vascular disease. Accordingly, ED and coronary artery disease share mutual risk factors and frequently coexist. Sexual health is an important aspect of our patients' lives, and ED is a common concern of the cardiovascular patient. Despite this, sexual function is under-addressed in the cardiac patient. Even when this topic is broached by the primary care physician or urologist, ED frequently remains untreated due to safety concerns involving cardiac disease and other comorbidities. This article describes our experience with this unique patient population, as well as our approach to building a multidisciplinary clinic designed to specifically address the important issue of ED in the cardiac patient.

EAU Guidelines on erectile dysfunction: an update

The introduction of new oral therapies has completely changed the diagnostic and therapeutic approach to erectile dysfunction. A panel of experts in this field has developed guidelines for the clinical evaluation and treatment based on the review of available scientific information.

An Overview of the Diagnosis and Treatment of Erectile Dysfunction

Epidemiological studies have demonstrated an age-stratified increase in the incidence and prevalence of erectile dysfunction (ED). There is a greater degree of openness today when discussing sexual matters and more information on the treatment of ED is available to the public through the media. Quality-of-life issues are now a matter of great importance to the aging population. Men and their partners are no longer prepared to merely accept ED as a natural consequence of aging. The advent of a simple and effective oral therapy for ED has also indirectly fueled the increase in treatment-seeking behaviour among men. Despite great strides in research into ED, our knowledge and understanding of the pathophysiological mechanisms is still in its infancy. As a result, we are able to treat only the symptom of ED rather than prevent it. Common diseases found in the population, such as diabetes mellitus and coronary artery disease appear to be risk factors for the development of ED. Therefore, physicians need to identify any underlying co-existing organic diseases in their patients presenting with ED. Whenever possible, patients are encouraged to attend their consultation sessions with their partners because ED is a condition affecting 'the couple' and not just the man. Psychogenic aspects of ED should also be explored during the consultation. Efforts need to be made to uncover and address the presence of any psychological stressors, if necessary with the help of a psychosexual therapist. The first-line treatment of ED is oral phosphodiesterase-5 inhibitors. For those who do not respond to oral therapy, there is no defined 'step-ladder' escalation in alternative therapy. It is up to the physician to discuss the options with the patient or couple and reach a decision based on their preference.

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.

Treatment for Erectile Dysfunction Based on Patient-Reported Outcomes

Erectile dysfunction (ED) is a common medical condition linked both to aging and to many medical conditions such as diabetes mellitus and cardiovascular disease. Although a common condition, treatment for ED has in the past been conducted by a few specialists, mostly urologists and sex therapists. The revolutionary introduction of oral therapy, and the massive amount of research into sexual dysfunction that followed, has led to paradigm shift in the treatment of ED. This is no longer something done by a few for a few; it involves all disciplines of medicine and more patients are being treated by a greater number of physicians. Several medications administered by different routes are available for treating ED but oral pharmacotherapy represents the first-line option. Phosphodiesterase (PDE) type 5 inhibitors are the most widely prescribed oral agents and they have a satisfactory efficacy-safety profile in patients of all categories. An alternative for men who do not respond to PDE5 inhibitors is intracavernosal injection therapy with alprostadil, a prostaglandin analogue. Other alternatives include sublingual apomorphine and intraurethral alprostadil. Both agents have a less satisfactory efficacy profile than PDE5 inhibitors and a low compliance rate. The aim of ED treatment is to restore an erection satisfactory for the sexual needs of the patient. Thus, the patient-reported outcome is the gold standard in efficacy evaluation. There are now three PDE inhibitors available, all with satisfactory efficacy-safety profiles, but with different pharmacokinetic properties. The availability of three different agents has initiated studies aiming to evaluate them regarding patient preference. However, the results are rather conflicting with some studies suggesting that tadalafil has the best patient preference, while others fail to demonstrate a clinically significant difference between the three agents. However, there is a tendency for younger men to choose tadalafil because it gives them a broader window of opportunity, while older men tend to prefer vardenafil or sildenafil. These data could be used when making a decision on which PDE5 inhibitor to prescribe, although another option is to let the patient try all three available agents and make his own choice.

Parkinson disease: an update

BACKGROUND

Over the past decade, the treatment of Parkinson disease (PD) has undergone tremendous changes. New drugs have been introduced to manage the cardinal motor symptoms of PD, and other agents have been borrowed to treat the nonmotor manifestations of the illness. For neurologists faced with the task of treating PD patients, the available array of medications may be confusing and intimidating.

REVIEW SUMMARY

In this review, I summarize the newest approved medications for the treatment of PD, including the new dopamine agonists and catechol-O-methyl-transferase inhibitors. I also describe agents that are used to treat common problems in PD patients, including hallucinations, orthostasis, nausea, erectile dysfunction, depression, and memory loss. Guidelines for handling common scenarios in PD patients will be illustrated by 10 case histories. Finally, the most promising PD drugs that are currently in development will be reviewed.

CONCLUSIONS

Neurologists have a vast armamentarium to treat both motor and nonmotor manifestations of PD. Understanding this array allows the astute clinician to improve the lives of their patients with PD.

PROSPECTIVE, RANDOMIZED, CROSSOVER COMPARISON OF SUBLINGUAL APOMORPHINE (3 mg) WITH ORAL SILDENAFIL (50 mg) FOR MALE ERECTILE DYSFUNCTION

PURPOSE

We established the efficacy and safety of sublingual apomorphine compared with oral sildenafil in comparable groups of patients with erectile dysfunction (ED).

MATERIALS AND METHODS

This prospective, randomized, crossover study included 77 heterosexual men with ED of various etiologies and severities. A total of 62 men were randomized but only 34 were evaluable for efficacy and tolerability. The study started with a run-in period of 2 to 4 weeks. The first 4 weeks of treatment were followed by a washout period of 4 weeks, after which patients changed to the alternate treatment for an additional 4-week period. The sequence of the 2 treatments was established by a randomization list in blocks in closed packets. The primary efficacy end point was the percent of attempts resulting in erection firm enough for intercourse. Additional variables were the percent of attempts resulting in intercourse and improvement in ED, as evaluated by the erectile function domain score of the International Index of Erectile Function questionnaire.

RESULTS

Sildenafil was significantly more effective than apomorphine in regard to the percent of attempts resulting in erection firm enough for intercourse (85% vs 44%, p <0.0001) and actually resulting in intercourse (81% vs 43%, p <0.0001) as well as erectile function evaluated by the erectile function domain score of the International Index of Erectile Function (p <0.001). The incidence of adverse events was not significantly different for the 2 drugs. Although the number of patients was small, this study had strong statistical power due to the striking difference in results.

CONCLUSIONS

Sildenafil was significantly more effective than apomorphine for ED. No statistical difference in adverse events was noted.

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.

Specific aspects of erectile function in urology/andrology

The urologist/andrologist is the specialist responsible for diagnosis and treatment of health problems related to the genitourinary tract, and his or her participation in comprehensive care for a patient with erectile dysfunction (ED) is fundamental and often indispensable. The urologists/andrologists should characterize the origin of ED because of their knowledge and familiarity of all diagnostic tests and second- and third-line therapy. The origin of ED is important to determine for various reasons, such as young people suitable for etiologic treatment, medicolegal reasons, or patients' wishes for a better understanding of their condition. A review of the diagnostic tests available as well as indications for second- and third-line therapy is presented. The close relationship between ED and urological disorders, such as benign prostatic hyperplasia, prostate cancer and their treatments, and renal failure, in association with penile conditions like Peyronie's disease, priapism, and possible androgen deficiency in men older than 50 years, places the urologist at the center of integrated treatment of male ED.

Challenges in the assessment of erectile dysfunction and treatment with oral therapies: review with case examples

PURPOSE

To review the clinical dimensions, etiology, assessment, and treatment of erectile dysfunction (ED) and to increase awareness of oral therapies for this condition.

DATA SOURCES

Scientific literature, consensus guidelines, and manufacturers' product information and guidelines.

CONCLUSIONS

A prevalent condition, particularly in middle-aged and elderly men, ED is vastly underreported and undertreated. Oral therapies, including phosphodiesterase type 5 inhibitors, are effective and well tolerated in many patients and represent potential first-line treatments for ED.

IMPLICATIONS FOR PRACTICE

ED has been associated with both life-threatening illnesses and reduced quality of life. Improving recognition and treatment of this condition and counseling patients about ED represent important clinical opportunities. A broad and expanding array of ED treatments enable therapy to be individualized to the needs of patients and their partners.

Efficacy of apomorphine and sildenafil in men with nonarteriogenic erectile dysfunction. A comparative crossover study

To compare the efficacy of apomorphine and sildenafil in men with nonarteriogenic erectile dysfunction (ED), 40 men were studied. Post-injection penile peak systolic velocity was greater than 25 cm s(-1). Twenty men started on apomorphine 2 mg and 20 on sildenafil 50 mg, the doses titrated up to 3 and 100 mg, respectively, if necessary. After a 1-week washout period each group switched to the other treatment mode. Efficacy was the percentage of attempts resulting in erections firm enough for intercourse, based on an event log data. The majority (85%) of the men had concomitant diseases, risk factors for ED and 95% were heavy smokers. The overall success rate of apomorphine was 62.7%, compared with 73.1% of sildenafil (Yates-corrected chi-square, P < 0.0004). The response to apomorphine 2 mg and sildenafil 50 mg was age related. Sildenafil was statistically more effective than apomorphine in impotent men with normal penile Doppler. Given the contraindication of sildenafil in men taking nitrates and the quick time of action of apomorphine, the two drugs are satisfactory first line therapeutic tools in such individuals and the choice should be based on patient's needs and preferences.

Update on oral treatments for male erectile dysfunction

Impairment of erectile function compromises quality of life in millions of men and their partners, many of whom prefer to suffer in silence. It is important to maintain an elevated index of clinical suspicion in patients with erectile dysfunction (ED) risk factors (e.g. hypertension, diabetes, coronary heart disease). There remains a high rate of voluntary discontinuation of therapy associated with most treatment modalities. Since the introduction of sildenafil, a greater awareness and openness regarding the epidemiology and treatment of male erectile dysfunction has emerged. The development of newer and potentially more efficacious phosphodiesterase type 5 (PDE5) inhibitors will serve to treat an even greater number of patients, allowing once daily and more convenient dosing. An increased understanding of the physiological principles of penile erection has allowed the development of novel oral pharmacological therapies. The new agents offer a potential benefit in a broader range of patients and clinical situations. They may provide a more acceptable alternative than other more invasive options (intracavernosal/urethral injection, implant surgery). The dopamine agonist apomorphine acts on the central control of penile erection to allow a sublingual preparation to produce a prompt response. It is not contraindicated in patients on nitrate medication for coronary artery disease, or in patients with depression or on antidepressants. As with any other treatment, the clinician's responsibility in the care of ED patients does not end with the writing of a prescription. Adequate education and follow-up are needed to optimize the efficacy and safety of oral ED therapy. Furthermore, patients and their partners need to be advised that the agents are not effective in the absence of sexual stimulation. Communicating with both the patient and his partner in a discreet, non-judgmental manner that fosters the physician-patient alliance can facilitate the recognition and treatment of ED.

Erectile dysfunction: management update

Dramatic advances in the management of erectile dysfunction have occurred over the past decade. Oral therapy with vasoactive agents has emerged as first-line treatment and has transformed both the manner in which the public views erectile dysfunction and the way health care providers deliver care. Whereas an extensive investigation was previously common in the management of erectile dysfunction, recent treatment guidelines promote a more minimalist, goal-oriented approach. In this article, we review the physiology of erection, and the pathophysiology, diagnosis and clinical management of erectile dysfunction. We also present the existing evidence for the efficacy of 3 phosphodiesterase inhibitors, the most widely used class of agents for erectile dysfunction.

A comparative, crossover study of the efficacy and safety of sildenafil and apomorphine in men with evidence of arteriogenic erectile dysfunction

The aim of the study was to establish and compare the efficacy and safety of sildenafil and apomorphine in men with arteriogenic erectile dysfunction (ED). In all, 43 men with ED and postinjection max penile systolic velocity <25 cm/s in repeated Doppler ultrasonography were included. Of these, 24 men started on apomorphine 2 mg and 19 on sildenafil 50 mg, the doses titrated up to 3 and 100 mg according to effectiveness and tolerability. Safety was evaluated according to adverse events (AEs) and patient withdrawal. Efficacy was the percentage of attempts resulting in erections firm enough for intercourse, based on event log data. The incidence of AEs with apomorphine 3 mg was higher than with sildenafil 100 mg. Two men on apomorphine 3 mg discontinued treatment due to AEs. The overall success rate of sildenafil was 63.7% compared to 32.1% of apomorphine (Pearson chi(2), P<0.01). Of all men, 25 (58.1%) responded to sildenafil 50 mg without the need for dose increase, while only one responded to apomorphine 2 mg. The response to sildenafil 50 mg was age related (analysis of variance, p=0.04). Satisfaction was reported by 76.75 and 13.95% of patients for sildenafil and apomorphine, respectively, but 20.9% were not satisfied with any of the two drugs. In conclusion, this study provides clear evidence that sildenafil, even at 50 mg dose, is more effective than apomorphine 3 mg in men with arteriogenic ED. The fact that one out of five patients is not satisfied with the above-studied drugs shows that new oral agents need to be evaluated for the treatment of this disorder.

Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction

PT-141, a cyclic heptapeptide melanocortin analog, was evaluated following intranasal administration in healthy male subjects and in Viagra-responsive erectile dysfunction (ED) patients. Erectile response was assessed by RigiScan trade mark in healthy subjects without visual sexual stimulation (VSS) and in Viagra-responsive ED patients with VSS. In healthy subjects, mean C(max) and AUC((0-t)) increased in a dose-dependent manner. Median T(max) was 0.50 h and mean t(1/2) ranged from 1.85 to 2.09 h. In both studies, an erectile response induced by PT-141 administration was statistically significant, compared to placebo, at doses greater than 7 mg, with the onset of the first erection occurring in approximately 30 min. PT-141 was safely administered and well tolerated in both studies. A maximum-tolerated dose was not identified. Flushing and nausea were the most common adverse events reported in both studies and no clinically significant changes in vital signs, laboratory tests, ECGs, or physical exams were observed. Based upon its erectogenic potential and tolerability profile, PT-141 is a promising candidate for further evaluation as a treatment for male ED.

Emerging Pharmacologic Approaches for the Treatment of Lower Urinary Tract Disorders

Lower urinary tract disorders include disorders affecting continence (stress urinary incontinence, urge urinary incontinence, and benign prostatic hyperplasia) and male erectile dysfunction. Although none of these conditions are fatal, they affect overall quality of life. Throughout modern medicine the treatment of these conditions was limited to psychological counseling or surgical intervention. In recent years, research defining the physiological mechanisms of continence and male sexual function has aided in the pharmacologic design of approaches to these conditions. These agents can act both centrally or on the peripheral genitourinary smooth muscle to alleviate disease symptoms. Incontinence is primarily treated with agents that act directly on the bladder smooth muscle such as muscarinic antagonists. However, afferent blockade to attenuate the spinalbulbospinal reflex pathway including mixed norepinephrine/serotonin reuptake inhibitors may provide a key breakthrough. Erectile dysfunction treatment has been revolutionized via the discovery of the nitric oxide pathway and phosphodiesterase 5 inhibitors. New peripheral targets as well as centrally acting agents represent potential emerging therapies. In this review, the pharmacologic basis of treatment of these disorders is discussed with special emphasis on emerging new therapeutics.