Yohimbine for erectile dysfunction: a systematic review and meta-analysis of randomized clinical trials

Adverse events of herbal food supplements for body weight reduction: systematic review

Herbal weight-loss supplements are marketed with claims of effectiveness. Our earlier systematic review identified data from double-blind, randomized controlled trials for a number of herbal supplements. The aim of this systematic review was to assess all clinical evidence of adverse events of herbal food supplements for body weight reduction for which effectiveness data from rigorous clinical trials exist. We assessed Ephedra sinica, Garcinia cambogia, Paullinia cupana, guar gum, Plantago psyllium, Ilex paraguariensis and Pausinystalia yohimbe. Literature searches were conducted on Medline, Embase, Amed and The Cochrane Library. Data were also requested from the spontaneous reporting scheme of the World Health Organization. We hand-searched relevant medical journals and our own files. There were no restrictions regarding the language of publication. The results show that adverse events including hepatic injury and death have been reported with the use of some herbal food supplements. For herbal ephedra and ephedrine-containing food supplements an increased risk of psychiatric, autonomic or gastrointestinal adverse events and heart palpitations has been reported. In conclusion, adverse events are reported for a number of herbal food supplements, which are used for reducing body weight. Although the quality of the data does not justify definitive attribution of causality in most cases, the reported risks are sufficient to shift the risk-benefit balance against the use of most of the reviewed herbal weight-loss supplements. Exceptions are Garcinia cambogia and yerba mate, which merit further investigation.

Internet websites selling herbal treatments for erectile dysfunction

The objective of the study was to investigate the safety and reliability of internet websites selling and providing medical information regarding herbal substitutes for Viagra. Using keywords 'Herbal' and 'Viagra', websites selling and providing medical information regarding herbal substitutes were identified. The top 50 sequential sites were assessed for safety and reliability against the Health on the Net (HON) criteria. Medically trained staff provided information in only 21% of the sites yet just 24% stated that the information was not a replacement for medical advice. No sites warned patients about erectile dysfunction (ED)-associated cardiovascular disease. In all, 88 and 70% of sites indicated drug efficacy and ingredients but only 36 and 21% provided contraindications and side effects, respectively. All sites fell short of the HON requirements. In conclusion, acquiring medical information and herbal substitutes for ED from the internet is convenient and easy. However, patients should be cautious as safety and reliability of this approach is poor.

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.

Erectile dysfunction: evaluation and new treatment options

OBJECTIVE

Erectile dysfunction (ED) is a common condition of aging men. Indeed as many as 50% of men over age 40 will suffer some degree of ED. This erectile dysfunction has substantial impact on interaction with their partners, families, and employment. ED may be a harbinger of more serious vascular events and is commonly associated with depression.

METHODS

Evaluation of ED begins with a careful history, asking the patient about his sexual function during clinical visits. Once identified, ED must be carefully considered with full history, careful physical examination, and laboratory studies to include markers of vascular risk factors, diabetes, and hypogonadism.

RESULTS

The treatment of ED was revolutionized by the introduction of phosphodiesterase type 5 (PDE5) inhibitors in 1998. Currently, 3 PDE5 inhibitors are available internationally with excellent expected results and somewhat unique profiles. Although these agents are safe in all patients who do not have severe cardiac disease or who are taking nitrate medications, they require some patient instruction and counseling to optimize results. In that small group of patients who do not respond to these oral medications, additional alternatives are available for patients motivated to pursue treatment of their ED.

CONCLUSION

Currently available safe and effective alternatives for the treatment of ED can improve the lives of patients and partners and increase their quality of life.

Prevention and treatment of erectile dysfunction using lifestyle changes and dietary supplements: what works and what is worthless, part II

It seems naïve to believe that some plants or herbs do not contain specific compounds that could benefit patients with ED. Many supplements have not been investigated in a laboratory or clinical research setting before commercial sale, however,which creates a complex situation. If efficacy is or is not demonstrated through adequate research, then the benefit or lack thereof cannot be mentioned on the label. Furthermore, clinicians and the public cannot be made aware of which compounds or supplements are effective because no general standards for sale exist under the current guidelines. Dietary supplements have received a tremendous amount of publicity. The large and growing market for ED treatment seems to have contributed partly to the promotion of numerous supplements and their apparent benefits. Whether these dietary supplements have merit is questionable. Some supplements may produce results opposite to those advertised. Other supplements may be enjoying the benefits of the placebo effect. Because a placebo response of 25% to 50% has been recorded in clinical trials with effective agents, it is understandable that some supplements enjoy financial success despite the limited research espousing their use. If one to two of four individuals or one of three individuals who try a dietary supplement gain some benefit for their ED, the market for these supplements will remain extraordinary. On a larger scale, of 100,000 men who try a supplement, approximately 25,000 to 50,000 will claim some success. The challenge for clinicians is to discuss the placebo response properly and the need for good research before any intervention, especially supplements, can be advocated for general use. Table 2 summarizes some popular ED supplements and general conclusions that can be drawn from clinical investigations. Some dietary supplements may have an active ingredient that benefits patients with certain types of ED. An exciting area of future dietary supplement research is the ability of certain agents to have a synergistic effect with prescription agents for ED, thereby improving response rates in men that have failed approved ED therapy initially, especially with oral agents. Randomized clinical trials are the best method of determining which dietary supplements will become a part of conventional medicine. Therefore, more randomized trials for dietary supplements are needed so that they may have the opportunity to become a part of the mainstream milieu, which means that more funding needs to be made available for ED research. The coming years of research should bring enormous excitement and objectivity to this area of medicine.

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.

New Treatment Options for Erectile Dysfunction in Patients with Diabetes Mellitus

Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis. Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice. The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals. The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent. Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively. Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.

Tratamiento con doxazosina en 3.347 pacientes con síntomas del tracto urinario inferior. efecto sobre su función sexual. estudio impros

OBJECTIVES

An open, non-comparative, multicenter study was performed to ascertain the prevalence in Spain of erectile dysfunction (ED) associated to benign prostatic hypertrophy (BPH), with moderate to severe urinary symptoms, and to confirm the improvement or disappearance of ED in response to treatment with 4 mg/day of Doxazosin.

METHODS

Out of the 3901 patients recruited 3545 took the medication and 3347 completed all the protocol visits. BPH patients were considered to have some degree of erectile dysfunction when they reported a difficulty for obtaining and/or maintaining an erection in the four weeks prior to their inclusion in the study (questions 3 and 4 of the International Index of Erectile Function). All the patients were treated with Doxazosin at increasing doses: from 1 mg/day up to 4 mg/day thereafter until 6 months of medication were completed.

RESULTS

The mean number of patients showing erectile dysfunction was 69.1%, ranging from 48.3% in the 40-49 years age group to 76.3% in the group aged from 60 to 69 years. In most Spanish regions, the prevalence of ED ranged from 76.9% in Cantabria to 67.2% in Aragon. The mean number of patients in whom erectile dysfunction disappeared after treatment, with a 95% confidence interval, was 4.5%, ranging from 17.5% in the 40-49 age group to 1.1% in the over 70s.

CONCLUSIONS

ED is a symptom very often associated to BPH, even in relatively young men. Doxazosin appears to have a beneficial effect in ED improvement, particularly in the younger patients.

Qualitative and quantitative determination of yohimbine in authentic yohimbe bark and in commercial aphrodisiacs by HPLC-UV-API/ MS methods

The development and validation of a rapid qualitative and quantitative method based on an HPLC-UV-MS technique with atmospheric pressure chemical ionisation and electrospray ionisation for the analysis of yohimbine in a number of commercial aphrodisiac products is reported. HPLC with multiple-stage mass spectrometry experiments allowed the identification of the target compound and increased the selectivity of complex analyses such as those involved with multi-botanical preparations. The precision and the robustness of the method were improved by the use of two internal standards: codeine for UV detection and deuterium-labelled yohimbine for MS detection. Twenty commercial aphrodisiac preparations were analysed and the amount of yohimbine measured and expressed as the maximal dose per day suggested on product labels ranged from 1.32 to 23.16 mg.

Erectile dysfunction

Erectile dysfunction (ED) is a highly prevalent and often undertreated condition. It may be a symptom of underlying, chronic illness and can have a negative impact on quality of life, psychosocial health, and relationships. The aging of the population, as well as the introduction of new treatment options, such as sildenafil, has led to increased public awareness of this disorder. New oral therapeutic agents are on the horizon. This article provides an overview of the physiology of erection, the pathophysiology of ED, and modern patient evaluation. Management options, including traditional therapeutic approaches as well as the new generation of oral agents, are also presented.

Recent findings on natural products with erectile-dysfunction activity

Viagra has had a profound influence on the search for natural products with erectile-dysfunction activity. To date the "natural" equivalent is not in existence but several pure compounds from nature, e.g., Yohimbine, Citrulline, two pyrano-isoflavones, berberine, forskolin and others, have either been re-examined or are new potential candidates. Intense activity exists in the area of testing semi-purified plant extracts for erectile dysfunction activity.

Current oral treatments for erectile dysfunction

Erectile dysfunction (ED) is defined as the inability to achieve and maintain a penile erection adequate for satisfactory sexual intercourse. It is a significant male health problem of global dimensions affecting approximately 150 million men worldwide. A broad range of options are currently available for the management of ED. They include oral agents (phosphodiesterase 5 inhibitors, dopamine agonists and alpha-receptor blocking drugs), intracavernosal injection (papaverine, phentolamine, prostaglandin E1, vasoactive intestinal peptide), transurethral vasoactive agents (prostaglandin E1), vacuum erection devices, vascular surgery and penile prostheses. Here we review the physiology of penile erection and the currently available oral preparations. In addition, novel therapeutic strategies to improve erectile function are discussed.

[Erectile dysfunction]

In Spain, based on the IIEF, 19% of males between 25 and 70 years old present some degree of erectile dysfunction (ED). Therefore, around 2,000,000 Spanish men present this condition and could require medical attention for it. Here, we present an up-date of the most important aspects of erectile dysfunction (pathophysiology, diagnosis and treatment). We review, in detail, the oral treatments and future drugs that are presently in the premarketing experimental phase. Diagnostic and therapeutic management of the patient with erectile dysfunction should be individualized, taking into account the goals of each patient. It is highly recommendable to carry out a basic assessment (comprehensive clinical history, physical examination, recommended lab testing). If previously undiagnosed diseases are discovered (diabetes, arteriosclerosis, etc.) these should be treated and modifiable risk factors should be corrected. There are numerous therapeutic options for the treatment of erectile dysfunction. Replacement therapy with testosterone should only be used in males with ED and low levels of this hormone, under medical supervision. At present, first line treatment consists of the administration of oral drugs (sildenafil, apomorphine). There are two new PDE 5 inhibitors (tadalafil and vardenafil) that will be released on the market 2003, which will provide better selectivity. Moreover, several drugs for oral administration are in the initial phases of research that will facilitate erection via a direct penile action. When oral drugs are contraindicated, are not effective or when they are unpopular with the patient, the second line of treatment is intracavernous injection. Prostaglandin E1 is the initial drug of choice in patients using intracavernous autoinjection for the first time and has a high efficacy. Implantation of a penis prosthesis and penile revascularisation are appropriate for highly selected patients. Psychotherapy can be an option for men with ED of psychogenic origin, either as a monotherapy or combined with sildenafil or apomorphine.

Endothelium-dependency of yohimbine-induced corpus cavernosum relaxation

Development and maintenance of penile erection requires the relaxation of the smooth muscle cells in the cavernous bodies and is essentially mediated by nitric oxide (NO). The penile flaccid state is conversely maintained by the alpha adrenergic neuroeffector system and by other vasoconstrictors, such as endothelin-1 (ET-1). In this study we examined the mechanisms involved in yohimbine-induced relaxation in human and rabbit corpora cavernosa (CC). We essentially found that yohimbine not only blocks contractions induced by adrenergic agonists, but also by non-adrenergic substances, such as ET-1. This effect was unrelated to antagonism at the level of ET receptors, because yohimbine did not affect ET-1-induced increase in intracellular calcium in isolated CC cells. Conversely, our data suggest that yohimbine counteracts ET-1-induced contractions by interfering with NO release from the endothelium. In fact, yohimbine-induced CC relaxation was inhibited by the mechanical removing of the endothelium and by blocking NO formation or signalling via guanylate cyclase and cGMP formation. Conversely, yohimbine activity was strongly increased by inhibiting cGMP degradation. In an experimental model of hypogonadism, performed on rabbits by chronic treatment with a long-lasting GnRH agonist, the relaxant yohimbine activity was also decreased, but completely restored by androgen supplementation. This effect was evident only in preparations in which the main source of NO was present (endothelium) or in which NO formation was not impaired by L-NAME. Our data indicate that the relaxant effect of yohimbine is both endothelium and androgen-dependent. This might justify the lack of efficacy of this drug in treatment of some form of organic erectile dysfunction.

Interactions between drugs for erectile dysfunction and drugs for cardiovascular disease

The association of erectile dysfunction (ED) and cardiovascular disease is well-documented in the literature and both conditions share risk factors. Therefore, it is difficult to distinguish the effect of underlying disease and adverse effects of the drugs and/or interactions between ED drugs and drugs implemented for cardiovascular disease. The known interactions of systemic administered drugs for ED with drugs for cardiovascular disease are mainly pharmacodynamic. Thus, nitrates enhance the production of cyclic GMP and combined with phosphodiesterase type-5 inhibitors this can lead to severe hypotension. The same is the case for the treatment with phentolamine in patients treated with beta-adrenoceptor antagonists. Due to increased partial thromboplastin time, the risk of bleeding is enhanced for intracavernous alprostadil injection in heparin-treated patients. Pharmacokinetic interactions of clinical importance have been described for ED drugs with other therapeutic groups such as sildenafil with the antifungal drug, ketoconazole, and apomorphine with the antiparkinson drug, entacapon. Although sildenafil and antihypertensive dihydropyridines like amlodipine are metabolized by the same cytochrome P450 enzyme, CYP3A4 in the liver, the combination of these drugs does not exhibit a synergistic blood pressure lowering action. Unfortunately documentation concerning drug interactions is often poor and occasional.

Pharmacological aspects of erectile dysfunction

Erectile dysfunction (ED) is a common problem with a prevalence of approximately 50% in men aged 40 to 70. There are several etiologies for ED including vasculogenic, neurogenic, hormonal and/or psychogenic factors; one-fourth of ED cases can be drug-related. Penile erection involves a complex interaction between the CNS and local factors. It is a neurovascular event modulated by psychological and hormonal factors. Pharmacologically, neural modulation and endocrine status are very important to attaining penile erection. There have been several significant advances for the pharmacologic treatment of ED. Treatments include agents that are not only orally effective, but possess either local or central acting mechanisms of action. Apomorphine, a centrally-acting agent, is effective in the treatment of ED. Sildenafil, another orally effective agent, acts by inhibiting cyclic GMP-specific phosphodiesterase Type V. Testosterone can be effective transdermally. Non-orally active agents include alprostadil and papaverine. Phentolamine and trazodone are effective in selected cases. Some agents can interact with other medications. Several pharmacological agents, some with central-acting mechanisms and some with Iocally-acting vascular effects, are therapeutically useful in the treatment of ED.

Yohimbine treatment of organic erectile dysfunction in a dose-escalation trial

Yohimbine has had questionable effects in men with organic erectile dysfunction. We conducted this study to better define the population of men responsive to yohimbine, because tobacco was thought to affect a regimen of yohimbine more than other risk factors. We measured nocturnal penile tumescence with the RigiScan monitor, hormone profiles, answers to the Florida Sexual Health Questionnaire, and clinical responses at baseline and after two different doses of yohimbine in 18 nonsmoking men with erectile dysfunction. Of the 18 men, nine (50%) were successful in completing intercourse in more than 75% of attempts. The yohimbine responders were men with less severe erectile dysfunction as manifested by improved increased rigidity on RigiScan testing, higher Florida Sexual Health Questionnaire scores, and slightly higher levels of serum testosterone. Yohimbine is an effective therapy to treat organic erectile dysfunction in some men with erectile dysfunction.

Dietary supplements and other alternative medicines for erectile dysfunction. What do I tell my patients?

Dietary supplements and other alternative medicines have enjoyed a tremendous amount of popularity and use over the past decade. Although, the prevalence of these therapies for erectile dysfunction (ED) is unknown at this time, numerous media outlets and alternative medicine publications seem to support the utilization of these therapies for ED. The placebo effect is approximately 25% (1 out of 4 benefit) from past randomized trials of FDA approved medications for ED. Adequate clinical trials are needed for dietary supplements for ED to access whether or not a benefit beyond a placebo effect exists. Clinicians should become aware of these supplements and the current research espousing or discouraging their use, and they should understand the adverse effects associated with them in order to effectively discuss these products with any patient inquiring about them.

Creative-dynamic image synthesis: a useful addition to the treatment options for impotence

In contrast to the impressive advances made in somatic research on erectile dysfunction, psychogenic erectile dysfunction is usually treated as a monolithic block. In this study, we evaluated the erectogenic power of creative-dynamic image synthesis in men with psychogenic erectile dysfunction. Sixty-nine men with a mean age of 46 y, suffering from erectile dysfunction of no known organic cause, were entered in a placebo-controlled study in which the erectogenic power of imagination, yohimbine and a placebo were compared. There was a significant difference between the subjective results of creative-dynamic image synthesis (75% increase of potency) and those achieved through treatment with the drug yohimbine (55% increase in potency) and with a placebo (30% increase in potency). Creative-dynamic image synthesis is a potent initiator of erections in men with psychogenic erectile dysfunction, has no known side effects and is very cost-effective.

A risk-benefit assessment of sildenafil in the treatment of erectile dysfunction

Sildenafil is an oral treatment for erectile dysfunction (ED). It acts as an inhibitor of 3',5'-cyclic guanosine monophosphate-phosphodiesterase type 5. An effective treatment for ED is required to produce an erectile response sufficient for satisfactory sexual performance. This has been documented for sildenafil in men with ED of differing aetiologies and baseline severity in various types of clinical trials. Sildenafil treatment is characterised by a good tolerability profile and low treatment digcontinuation rate caused by treatment-related adverse effects. Most of the adverse effects associated with sildenafil are extensions of the pharmacological action of the drug. There is no significant difference in the adverse effect profile (headache, flushing, dyspepsia, nasal congestion and abnormal vision) of this agent as assessed by clinical data obtained either in the pre- and postlaunch periods. Because of its acceptable risk-benefit ratio, sildenafil can be prescribed to a very large group of patients with ED. The reports of serious cardiovascular events associated with the use of sildenafil (including anecdotal reports of deaths) have been very thoroughly analysed. A number of studies have not shown any difference in the risk of serious cardiovascular events in sildenafil- and placebo-treated patients. However, when making a risk-benefit evaluation, certain subgroups of patients need to be considered separately. In particular, sildenafil is contraindicated in patients receiving nitrate therapy. In some other subgroups of patients, the risks and benefits of treatment need to be assessed on an individual basis and it is hoped that additional data will clarify any possible risks associated with sildenafil administration such patients. It is helpful to compare the risk-benefit profile of sildenafil with the characteristics of other oral drugs for ED. According to the preliminary data, apomorphine and phentolamine are possible future options for the treatment of ED; however, there needs to be further clinical evaluation of these agents. Initial data have shown that sildenafil can be successfully combined with intracavernosal injection in patients nonresponders to either therapy. In conclusion, favourable characteristics make sildenafil suitable for the first-line therapy for a substantial proportion of patients with ED.

Yohimbine: a clinical review

Although yohimbine (YOH) has been available for the treatment of male erectile dysfunction (ED) for longer than Viagra, there is a perception that little is known about the clinical performance of the drug. This review attempts, by comprehensive analysis of the literature, to cover the clinical, pharmacological, and therapeutic profiles of YOH, relevant to its potential utility in the management of patients with ED. Relatively few well-designed studies have been completed. From these, however, it can be concluded that YOH as monotherapy possesses only modest efficacy in ED patients. In acute and chronic (long-term) studies, YOH has been found to be relatively free of side effects over the dose range predicted to be effective in ED. At much higher doses, the most frequently observed effects, consistent with the primary pharmacological action of the drug, are elevation of blood pressure, a slight anxiogenic action, and increased frequency of urination. These side effects are all easily reversible on termination of YOH therapy. There is increasing evidence that the erectogenic action of YOH can be augmented by concomitant administration of agents that augment the release and/or action of nitric oxide in the corpus cavernosum. YOH has yet to be studied in female sexual dysfunction. Overall, the benefit risk profile of YOH would indicate that it has potential, more probably as part of a combination strategy, e.g., with a drug that enhances the nitric oxide pathway, in the treatment of ED.

Systematic reviews of complementary therapies - an annotated bibliography. Part 2: herbal medicine

BACKGROUND

Complementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with herbal medicine. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of herbal medicines; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pre-tested form and summarized descriptively.

RESULTS

From a total of 79 potentially relevant reviews pre-selected in the screening process 58 met the inclusion criteria. Thirty of the reports reviewed ginkgo (for dementia, intermittent claudication, tinnitus, and macular degeneration), hypericum (for depression) or garlic preparations (for cardiovascular risk factors and lower limb atherosclerosis). The quality of primary studies was criticized in the majority of the reviews. Most reviews judged the available evidence as promising but definitive conclusions were rarely possible.

CONCLUSIONS

Systematic reviews are available on a broad range of herbal preparations prescribed for defined conditions. There is very little evidence on the effectiveness of herbalism as practised by specialist herbalists who combine herbs and use unconventional diagnosis.

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.

Pharmacology of erectile function and dysfunction

Central regulation of the erectile process involves several transmitters, including dopamine, serotonin, noradrenaline, and nitric oxide, and peptides, such as oxytocin and ACTH/alpha-MSH. These systems may be targets for future drugs designed to treat erectile dysfunction. Peripherally, the different steps involved in neurotransmission, impulse propagation, and intracellular transduction of neural signals in penile smooth muscles need further investigation. Continued studies of the interactions between different transmitters/modulators may reveal new combination therapies. Increased knowledge of the changes in penile tissues associated with erectile dysfunction may explain the pathogenetic mechanisms and help to prevent the disorder.

Subjective visual halos after sildenafil (Viagra) administration: Electroretinographic evaluation

PURPOSE

The ophthalmologic and electroretinographic (ERG) findings in one subject with subjective visual disturbances after sildenafil administration are described.

DESIGN

Interventional case report.

METHODS

A complete ophthalmologic examination was performed, including best-corrected visual acuity and ERG, repeated 1 and 2 hours after administration of 100 mg of sildenafil.

MAIN OUTCOME MEASURES

Rod responses were obtained over a range of retinal illuminances from those producing a minimum detectable response to those producing rod saturation. Intensity amplitude function was determined.

RESULTS

At 2 hours after 100 mg of oral sildenafil, we observed significant variations from baseline in parameters of best-fit Naka-Rushton function; V(max) was notably higher, and K was 0.14 log units lower than baseline.

CONCLUSIONS

Sildenafil administration resulted in a higher rod response to light stimuli and in a higher rod sensitivity. These findings are consistent with the weak PDE-6 inhibition induced by sildenafil.

Central neural regulation of penile erection

Penile erection is caused by a change of the activity of efferent autonomic pathways to the erectile tissues and of somatic pathways to the perineal striated muscles. The spinal cord contains the cell bodies of autonomic and somatic motoneurons that innervate the peripheral targets. The sympathetic outflow is mainly antierectile, the sacral parasympathetic outflow is proerectile, and the pudendal outflow, through contraction of the perineal striated muscles, enhances an erection already present. The shift from flaccidity to erection suggests relations among these neuronal populations in response to a variety of informations. Spinal neurons controlling erection are activated by information from peripheral and supraspinal origin. Both peripheral and supraspinal information is capable of eliciting erection, or modulating or inhibiting an erection already present. One can hypothesize a spinal network consisting of primary afferents from the genitals, spinal interneurons and sympathetic, parasympathetic and somatic nuclei. This system is capable of integrating information from the periphery and eliciting reflexive erections. The same spinal network, eventually including different populations of spinal interneurons, would be the recipient of supraspinal information. Premotor neurons that project directly onto spinal sympathetic, parasympathetic or somatic motoneurons, are present in the medulla, pons and diencephalon. Several of these premotor neurons may in turn be activated by sensory information from the genitals. Aminergic and peptidergic descending pathways in the vicinity of spinal neurons, exert complex effects on the spinal network that control penile erection. This is caused by the potential interaction of a great variety of receptors and receptor subtypes present in the spinal cord. Brainstem and hypothalamic nuclei (among the latter, the paraventricular nucleus and the medial preoptic area) may not necessarily reach spinal neurons directly. However they are prone to regulate penile erection in more integrated and coordinated responses of the body, such as those occurring during sexual behavior. Finally, the central and spinal role of regulatory peptides (oxytocin, melanocortins, endorphins) has only recently been elucidated.

Alternative therapies for menopause

If a woman does not want to use, or cannot use, hormone replacement therapy, then she must consider other ways to address two issues related to menopause: reducing her risk of developing cardiovascular disease, osteoporosis, and other health problems that increase as women age, and symptomatology. Risk reduction of an array of health problems can be achieved through diet, exercise, and stress management. The nutraceuticals of specific vitamins, minerals, phytoestrogens, and essential fatty acid supplementations are a vital component of the risk reduction health program. Risk reduction of osteoporosis can be enhanced specifically through the use of ipriflavone and a comprehensive "bone building" vitamin and mineral program. Control of homocysteine levels for prevention of CAD, osteoporosis, and other health problems can be accomplished through B vitamin supplementation. The same interventions for risk reduction also may prove to be effective in prevention and treatment of menopausal-related symptoms, particularly when the B vitamins, magnesium, isoflavones, and essential fatty acids are used. If lifestyle interventions and nutraceuticals do not adequately address symptomatology, however, a woman has several alternative therapies from which to choose. There are numerous excellent multiherbal and homeopathic therapies that can be purchased over the counter. A woman also can choose to be evaluated by an alternative therapy practitioner and have a program designed specifically for her health needs. Although there has been limited clinical research of herbal and homeopathic alternative therapies for the menopause, when taken according to directions and if no contraindications exist, they have the potential for being extremely effective and safe options.

Non-surgical management of erectile dysfunction

Erectile dysfunction is a common and distressing medical condition that is now highly amenable to treatment almost irrespective of the cause. Safe, non-surgical treatments with unequivocal efficacy are psychological therapy, intracorporeal injection of vasoactive drugs, transurethral vasodilators and oral sildenafil, all of which have been reported to have a 50-70% overall response rate. Vacuum constriction devices are acceptable for some, usually older patients and oral yohimbine is thought to have marginal efficacy. Local creams to induce or enhance erectile function are currently being investigated. There is no place for androgen supplementation unless the patient is profoundly hypogonadal. Treatment of hyperprolactinaemia is very effective but is a rare cause of erectile dysfunction. As intercourse may entail an unfamiliar level of physical activity, it is sensible to ensure that the patient is able to climb a flight or two of stairs comfortably without provoking undue breathlessness or chest pain and to provide suitable advice about technique before commencing treatment. Once it is clear to the patients that erectile dysfunction can be satisfactorily overcome, the long-term use of treatments to do so tends to wane. Thus, although the prospect of effective treatment for what had been for many a distressing life sentence has the potential to place new demands on the health service, there is no evidence that restrictions on prescribing will prove economically rational.

Physiology and pathophysiology of erection: consequences for present medical therapy of erectile dysfunction

Smooth muscle relaxation of the corpus cavernosum is the key mechanism of erection. It depends on a cascade of consecutive regulatory systems starting in the central nervous system, and proceeding via peripheral neurotransmission to intracellular signal transmission within the cavernous smooth muscle cells. Knowledge of these interacting mechanisms of erection is fundamental for understanding of the mode of action of new and possibly selective pharmacological agents that are presently available or under evaluation for treatment of erectile dysfunction.

Erectile function and dysfunction

The advent of "the pill" for erectile dysfunction has prompted discussion in the news as well as jokes on late-night talk shows. However, the underlying causes of the condition are complex, and no single treatment is right for all patients. To select the best therapy for each patient, it is important to understand how an erection works and how the available treatments address the various causes of dysfunction. Dr Jordan presents a comprehensive, straightforward (sometimes humorous) look at the mechanisms involved in erectile function and offers an approach to management of dysfunction.

Assessment and management of erectile dysfunction in men with diabetes

PURPOSE

Erectile dysfunction occurs earlier in men with diabetes than in the general population, affecting over 50% of male patients by age 60. This article summarizes the etiologies and presents methods of patient assessment and treatment options for erectile dysfunction.

METHODS

Assessments of neurologic and vascular complications related to diabetes should be included in a sexual function history. The assessment must be holistic and focus on organic as well as psychogenic causes. Diabetes educators must be prepared to discuss the various pharmacologic treatment options.

RESULTS

Sildenafil currently is the only oral medication available for erectile dysfunction. Injectable treatments have proven successful but with limited long-term use and poor patient acceptance. Implantable devices carry surgical risk and increased rates of infection.

CONCLUSIONS

All men with diabetes should be screened for erectile dysfunction. The availability of a new oral medication provides a patient-acceptable treatment option.

Opportunities for the treatment of erectile dysfunction by modulation of the NO axis--alternatives to sildenafil citrate

Erectile function in man depends upon a complex interaction of psychogenic, neurologic, hormonal and vascular factors, and therefore the management of erectile dysfunction (ED) reflects this complexity of control. Therapeutic options include psychological and non-pharmacological approaches as well as drug treatments. The effectiveness of the type-5 cGMP phosphodiesterase inhibitor sildenafil citrate (Viagra) confirms the pivotal role of the NO-cGMP axis in promoting and maintaining erection. Although widely acclaimed, sildenafil leaves many questions unanswered, especially regarding its susceptibility to pharmacokinetic drug interactions, and its safety in patients with ischaemic heart disease and those taking nitrates. In view of the epidemiological link between erectile dysfunction and cardiovascular disease in the elderly, this limitation might have much broader implications. The presently available scientific documentation, although less extensive, indicates that NO donors, such as topically applied nitroglycerin (GTN; for example, 1-2 puffs of an ordinary GTN spray applied to the shaft of the penis), might be a reasonable alternative. Further larger-scale research on the efficacy and tolerability of topical GTN is needed to establish its full therapeutic potential in the treatment of erectile dysfunction.