Testosterone and erectile dysfunction

Aging is associated with a decline in several important health factors in men, including libido. Serum testosterone concentrations also decrease with age, and many age-related clinical features are closely associated with androgen deficiency, including erectile function (ED). Approximately 70% of ED is of organic origin, with the major risk factors being diabetes mellitus, hypercholesterolemia, smoking and chronic medical illnesses. These are also established risk factors for atherosclerosis, which is the predominant predisposing factor of vasculogenic ED. The introduction of phosphodiasterase-5 (PDE-5) inhibitors for the treatment of ED made a significant impact both in terms of clinical efficacy, and increasing the awareness of the condition. In spite of this, some patients fail to respond to PDE-5 inhibitors alone. Both animal and clinical studies indicate that testosterone therapy improves both erectile function and the response to PDE-5 inhibitors in patients with ED and hypogonadism. Indeed, interventional studies demonstrate that testosterone replacement therapy improves erectile function in hypogonadal men who have previously failed to respond to PDE-5 inhibitors alone. Furthermore, it has been demonstrated that the full therapeutic potential of PDE5 inhibitors will only become manifest in a eugonadal state. Recent studies have demonstrated a close relationship between testosterone and ED and suggest that testosterone therapy may be a valuable option for an increasing number of affected men. European guidelines recommend that all men presenting with ED should have their testosterone concentrations measured.     

Testosteron und erektile Dysfunktion

Primary hypogonadism represents a classic but rare cause of erectile dysfunction (ED) in men. Therapy with testosterone as monotherapy is therefore unlikely to cure ED in the typical ED patient. However, recent developments indicate a much greater role of testosterone in erectile function than has been supposed in the past. Serum testosterone levels decline in men with increasing age. Aging men might develop late-onset hypogonadism (LOH) associated with characteristic symptoms. Typical symptoms of LOH are represented by decreased libido and sexual function, osteoporosis, altered distribution of body fat, overall reduction in physical strength, and alterations in the general mood. Experimental and clinical studies over the last few years have also pointed out that hypogonadism results in characteristic alterations of the erectile tissue of the penis. These alterations might be reversible in response to hormone therapy with testosterone. Particularly testosterone might be a helpful supportive therapy in cases where PDE-5 antagonists have tended to lose their effectiveness on the erectile tissue in the treatment of ED.     

Testosterone and erectile dysfunction

The role of testosterone on sexual desire, interest and motivation is well established, but its effects on erectile function remain controversial. Animal data show that experimental or medical castration results in loss of the intracavernosal pressure, smooth muscle/connective tissue balance, and penile tissue concentration of nitric oxide synthase-containing nerves, which alter the fibroelastic properties of penile tissue compliance, leading to veno-occlusive dysfunction and therefore erectile dysfunction. Castration also induces apoptosis of penile erectile tissue, and new DNA synthesis is induced by treatment with testosterone. In an animal model of venogenic erectile dysfunction, intracavernous vascular endothelial growth factor (VEGF), in addition to testosterone, restores the smooth muscle/connective tissue balance, endothelial cell hypertrophy and hyperplasia and normalizes the diameter of the dorsal nerve fibres, thereby preventing veno-occlusive dysfunction. There is some evidence that treatment with testosterone may be beneficial to men with erectile dysfunction who have low baseline testosterone levels. Androgens may also control the expression and activity of phosphodiesterase type-5 (PDE-5) in the penile corpus cavernosum. Oral drug therapy with PDE-5 inhibitors fails in some patients with erectile dysfunction. However, when testosterone is used together with a PDE-5 inhibitor, sexual function is restored in these patients, creating the potential for pharmacological combination therapy with testosterone for the treatment of erectile dysfunction.     

Synergetic effect of testosterone and phophodiesterase-5 inhibitors in hypogonadal men with erectile dysfunction: A systematic review

Testosterone deficiency seems to impair the clinical response to phophodiesterase-5 (PDE-5) inhibitors in patients with erectile dysfunction (ED). In hypogonadal men, testosterone repletion was associated with enhanced sexual function in patients who failed initial treatment with sildenafil or tadalafil. We conducted a systematic review of studies that evaluated combination therapy of testosterone and PDE-5 inhibitors in patients with ED and low, low-normal testosterone levels who failed monotherapy. The studies we examine are heterogeneous with several methodological drawbacks and that, overall, the addition of testosterone to PDE-5 inhibitors might benefit patients with ED associated with testosterone <300 ng/dL (10.4 nmol/L) who failed monotherapy. Further studies, with a randomized placebo-controlled and double blind design, are needed to describe the appropriate target patient group, testosterone cut-off and to define the optimal dose and duration of combination therapy.     

The relationship between hypogonadism and erectile dysfunction

It is well known that testosterone enhances sexual interest leading to an increased frequency of sexual acts and an increase in the frequency of sleep-related erections. However, it has little effect on fantasy- or visually induced erections. Exact contribution to erection from testosterone in men remains unclear. Animal studies have well demonstrated that testosterone plays critical physiological (activity of nitric oxide synthases and phosphodiesterases), biochemical (through an endothelial-independent pathway and adrenergic tonicity) and structural (change of fibroelasticity and hollow cell accumulation) roles in erectile function. The supplementation of testosterone to castrated animals can restore erectile function. Clinically, reports of patients with erectile dysfunction (ED) combined with hypogonadism who receive testosterone therapy have inconsistent results. However, testosterone may ameliorate the expression of the phosphodiesterase-5 (PDE5) inhibitor, and the use of testosterone in conjunction with the PDE5 inhibitor revealed convincing results. Because of potential risks in clinical use, testosterone therapy should be individualized, carefully considered and closely monitored, especially, in patients with possible occult prostate cancer, and large benign prostatic hyperplasia. Lower urinary tract symptoms might be worsened by this treatment, since the prostate is an androgen-dependent tissue.     

Effects of testosterone on erectile function: implications for the therapy of erectile dysfunction

Sexual potency declines with age, as does the efficiency of erection. Many studies show that different patterns of erectile dysfunction (ED), varying from occasional inability to obtain a full erection, impairment throughout intercourse and total absence of erectile response, might not be triggered by psychological factors only. Recent research indicates that ED relies on organic causes, and has challenged the development of new therapies. One therapeutic approach in patients who have testosterone deficiency is based on androgen therapy. Thus, we reviewed data on testosterone-induced effects relative to erectile function, summarizing the results from studies reported in 1991-2006 on testosterone therapy in patients with ED and hypogonadism, with a special focus on men not responding to phosphodiesterase-5 (PDE-5) inhibitors. We searched several computerized databases parallel with printed bibliographic references. Many studies have established animal models, which confirm that testosterone is important in modulating the central and peripheral regulation of ED. Testosterone deprivation has a strong negative impact on the structure of penile tissues and erectile nerves, which can be prevented by androgen administration. Combined therapy regimens with PDE-5 inhibitors and testosterone might improve ED in patients with hypogonadism of different causes. Thus, androgen treatment in hypogonadic patients, including those unresponsive to PDE-5 inhibitors, often results in an improvement of ED. Testosterone therapy is safe and convenient, while rapidly correcting low testosterone levels.     

勃起功能障碍全球视点:从科学进展到伴侣的解决方案——第一届亚太地区研讨会纪要

2006年2月24～26日,第一届“勃起功能障碍(ED)全球视点:从科学进展到伴侣的解决方案”亚太地区研讨会在中国上海举行。会议就男性的性健康问题、尤其是勃起功能障碍(ED)的最新科学数据及其对女性伴侣的影响进行了广泛的探讨。主要内容包括ED患者及其伴侣与医生这3者之间交流的重要性,女性伴侣在患者寻求和坚持药物治疗中的作用,慢性疾病对性健康的影响,睾酮在ED中的作用,特殊人群的性健康,如何进行个体化治疗以及如何获得成功的治疗反应,磷酸二酯酶5(PDE5)抑制剂(尤其是伐地那非)治疗ED的显著疗效和安全性,以及亚洲地区ED的治疗现状等。     

Hypogonadism and erectile dysfunction: the role for testosterone therapy

The role of low testosterone levels in erectile dysfunction (ED) remains unclear. Both organic and psychogenic factors contribute to ED, with vasculogenic causes being the most common etiology. Approximately 10-20% of patients with ED are diagnosed with hormonal abnormalities. At the physiologic level, two second messenger systems are involved in mediating erections, one involving cyclic adenosine monophosphate (cAMP) and the other involving cyclic guanosine monophosphate (cGMP). PDE5 inhibitors such as sildenafil promote the cGMP pathway, while alprostadil affects the cAMP pathway. Evidence is strong that, in animal systems, testosterone has direct effects on erectile tissue. However, although testosterone clearly has an impact on libido in humans, its effect on penile function is less clear. Evaluation of ED includes medical, sexual, and psychosocial history assessments, as well as laboratory tests to check for diabetes and hormonal abnormalities. Initial interventions should involve correction of potentially reversible causes of ED, such as hypogonadism. First-line therapy for other patients is typically oral PDE5 inhibitors, such as sildenafil, tadalafil, or vardenafil. For patients who fail treatment with PDE5 inhibitors, local therapies such as intracavernous alprostadil are highly successful. Recent data also support the success of combination therapy with sildenafil and testosterone. This opens the possibility of other combinations of testosterone and other treatments of ED. The ability to exploit multiple pathways in the physiologic processes leading to erection may help improve therapy for ED.     

Pilot study of the transdermal application of testosterone gel to the penile skin for the treatment of hypogonadotropic men with erectile dysfunction

Androgens influence important central and peripheral mechanisms of the erectile system. The relevance of a moderate decrease of serum testosterone level for erectile dysfunction (ED) has not been clarified so far. The aim of our study was to offer an easy transcutaneous method of androgen application. A previous study on the pharmacokinetic profile of the testosterone gel applied, showed marked elevation of the serum levels of testosterone. In our study, 46 hypogonadal patients with ED and total lack of vaginal penetration applied testosterone gel (4 mg/day; supplied by Azupharma, Germany) to the penile skin twice a day over 6–8 weeks, after a run-in period with placebo gel of 2 weeks. All patients showed decreased testosterone serum levels (<3 ng/ml) in at least two morning samples over a period of 3 weeks before treatment. Psychogenic etiology was excluded by a sexual psychologist. Patient age was 37–69 years (mean 53.5). Three patients (6.5%) responded to placebo in the run-in phase and were withdrawn from further treatment. Fifteen patients (32.6%) showed improved erection, allowing penetration and sexual intercourse. Twenty-eight patients (60.9%) did not respond to therapy. Local genital skin irritation was not observed. Elevation of peripheral testosterone was not correlated to a positive therapy response. A success-rate of 32.6% in this group of patients after exclusion of psychogenic patients and placebo-responders seems to justify further investigations. A medication period of 6–8 weeks is most probably too short to induce imaginable regenerative effects of testosterone on the erectile system. We therefore suggest that future double-blind and placebo-controlled studies should be designed for a minimum of 3 months. Testosterone gel may be a cost effective form of androgen administration.     

Combining testosterone and PDE5 inhibitors in erectile dysfunction: basic rationale and clinical evidences

INTRODUCTION: Erectile dysfunction (ED) and decline of testosterone levels are frequently observed with age and also in illnesses with a common basis of endothelial damage. OBJECTIVES: To review molecular mechanisms underlying androgen action upon its receptor and phosphodiesterase type 5 (PDE5) expression and regulation by testosterone in cavernous tissue and their clinical implication in the treatment of ED refractory to PDE5 inhibitors (PDE5-Is). METHODS: From January 2003 to May 2006 [corrected] we performed an extensive, unsystematic MEDLINE literature search reviewing relevant data on basic and clinical studies regarding the efficacy of combination therapies. RESULTS: Most trials using testosterone alone for treatment of ED in hypogonadal men suffer from methodologic problems and report inconsistent results, but overall the trials suggest that testosterone is superior to placebo. Orally effective PDE5-Is, such as sildenafil, tadalafil, or vardenafil, may be ineffective depending on the demonstration of testosterone regulation of PDE5 expression in human corpus cavernous, and their efficacy may be enhanced by testosterone adjunction whenever necessary. CONCLUSIONS: Screening for hypogonadism in all men with ED is necessary to identify men with severe hypogonadism and some cases of mild to moderate hypogonadism, who may benefit from testosterone treatment. Identification of threshold values for testosterone supplementation to appropriately benefit from PDE5-Is failure may improve clinical management of unresponsive patients with minimization of unwanted effects.     

DOES SILDENAFIL COMBINED WITH TESTOSTERONE GEL IMPROVE ERECTILE DYSFUNCTION IN HYPOGONADAL MEN IN WHOM TESTOSTERONE SUPPLEMENT THERAPY ALONE FAILED?

PURPOSE: We evaluated the efficacy of testosterone gel (T-gel) alone and in combination with sildenafil in hypogonadal patients with erectile dysfunction (ED). MATERIALS AND METHODS: A total of 49 hypogonadal men (mean age 60.7 years) with ED participated for a mean of 20.2 months. Blood was tested for total and bioavailable testosterone, and prostate specific antigen. Sexual function was assessed using the International Index of Erectile Function questionnaire and a global assessment question (GAQ). Men received 1% 5 gm T-gel for 6 months, and 100 mg sildenafil was added to those with a "no" response to the GAQ after 3 months on testosterone supplement. RESULTS: A total of 31 patients reported significant improvement in the sexual desire domain (from a mean +/- SD of 4.2 +/- 0.8 to 8.6 +/- 0.4) and erectile function (EF) domain (from 13.6 +/- 1.9 to 27 +/- 0.8) following treatment with testosterone supplement alone. One patient was excluded from study after urinary retention developed and 9 reported irritation at the gel application site. In spite of normalization of total and bioavailable testosterone values, and significant improvement of sexual desire domain scores, the EF of 17 men remained less than 26 or they responded "no" to the GAQ. These men received combined T-gel and sildenafil, after which all graded EF greater than 26 and responded positively to the GAQ. CONCLUSIONS: Combined treatment with sildenafil and T-gel has a beneficial effect on ED in hypogonadal patients in whom treatment with testosterone supplement alone failed.     

Efficacy of tadalafil in the treatment of erectile dysfunction in hypertensive men on concomitant thiazide diuretic therapy

Many men with erectile dysfunction (ED) have hypertension as a comorbid condition. Recent guidelines recommend thiazide diuretics as first-line therapy for hypertension. We analyzed data from 14 randomized, double-blind, placebo-controlled trials (N=2501) to evaluate the efficacy of tadalafil 20 mg for the treatment of ED in men on thiazides. Of the 2501 patients, 163 were on concomitant thiazides (116 tadalafil/47 placebo) and 159 (98%) were reported to have hypertension. The primary efficacy measures were mean change from baseline in the international index of erectile function (IIEF) erectile function (EF) domain and the proportion of 'yes' responses to sexual encounter profile (SEP) Questions 2 and 3. The tadalafil group showed a significantly (P<0.001) greater mean baseline to endpoint improvement on all efficacy outcome measures compared to placebo-treated patients regardless of concomitant thiazide use. More importantly, the responses to tadalafil were similar regardless of concomitant thiazide use. Additionally, responses to tadalafil were comparable between thiazide and nonthiazide users regardless of baseline ED severity (P>0.05).     

Testosterone improves erectile function in hypogonadal patients with venous leakage

The goal of this study was to assess the therapeutic benefits of long-acting testosterone therapy in hypogonadal patients with erectile dysfunction (ED). We recruited 29 patients with ED, ranging in age from 32 to 65 years (mean +/- SD, 47 +/- 9.7 years), with low plasma testosterone, who did not respond to phosphodiesterase type 5 inhibitor therapy. To evaluate penile arterial and venous blood flow, we employed duplex Doppler ultrasonography. For confirmation of diagnosis of venous leakage, pharmacocavernosography was carried out in 9 patients and magnetic resonance imaging with intracavernous contrast enhancement was carried out in 8 patients. All patients were treated with 1000 mg injectable testosterone undecanoate on day 1, followed by another injection after 6 weeks and every 3 months thereafter, in accordance with Nebido therapy protocol. Plasma testosterone levels were determined in all patients at baseline and after 18 and 30 weeks of testosterone treatment. The International Index of Erectile Function (IIEF-5) was administered at baseline and after 18 and 30 weeks of testosterone treatment. At baseline total testosterone ranged from 7 to 11.8 nmol/L (200 to 345 ng/dL) in 25 patients. Eighteen and 30 weeks after testosterone treatment, the mean testosterone plasma levels were 18 and 21.5 nmol/L (520 and 625 ng/dL), respectively. After 18 and 30 weeks of testosterone treatment, 20 out of the 29 patients demonstrated marked improvement in erectile function domain, as assessed by the IIEF-5. This was also associated with diminution of venous leakage. We suggest that, in hypogonadal men with ED, testosterone therapy improves erectile function in patients with ED and venous leakage.     

Significance of hypogonadism in erectile dysfunction

To review the role and significance of hypogonadism, defined as a low testosterone (T) level, in erectile dysfunction (ED). Review of literature. Serum T is below 3 ng/ml in 12% of ED patients, including 4% before and 15% after the age of 50. Replacement studies in men with severe hypogonadism demonstrate that sexual desire and arousal, as well as the frequency of sexual activity and spontaneous erections are clearly T-dependant. Psychic erections are partly T-dependant. The effects of T upon sexual function are dose-dependant up to a threshold level that is consistent within an individual, but markedly variable between individuals, ranging from 2 to 4.5 ng/ml. More evidence is required to confirm a significant impact of T on the intrapenile vascular mechanisms of erections in men as it is the case in animals. No convincing association of T with ED has been found in epidemiological studies. As concerns clinical experience, although a meta-analysis of the randomized controlled trials established that T therapy consistently restores erectile function in young hypogonadal patients with T below 3.46 ng/ml, the effects of this treatment have been mostly disappointing when used alone in older patients consulting for ED who are subsequently diagnosed to have hypogonadism following routine T measurement. These poor results may probably be explained by the high prevalence of co-morbidities, and by the fact that ED itself may induce hypogonadism. Combination therapy with T and PDE5 inhibitor (PDE5I) may be effective in the hypogonadal ED patients when T therapy alone fails. However, more evidence is required to confirm the hypothesis that a minimum level of T is required for a complete effect of PDE5I in certain men, since a PDE5I was able to restore complete erections in severely hypogonadal men. Though a low T level is not always the only cause of ED in hypogonadal ED patients, there are important benefits in screening for hypogonadism in ED. A low T level justifies a 3 month trial of T therapy, before combining a PDE5I if T therapy alone fails     

Sexual functions of men with obstructive sleep apnoea syndrome and hypogonadism may improve upon testosterone administration: a pilot study

This study examined 72 patients with obstructive sleep apnoea syndrome (OSAS), confirmed by polysomnography. Thirty-two patients were suffering from erectile dysfunction (ED) assessed by IIEF-5 questionnaires and confirmed by nocturnal penile tumescence examination. Their testosterone levels were measured. Eight patients had normal testosterone levels and were treated with a PDE-5 inhibitor (vardenafil) only; after 6 months of treatment, 6 of these patients (75%) showed significant improvement in erectile function. The remaining 24 patients with OSAS, ED and hypogonadism (total testosterone <12 nmol l⁻¹), were divided into two groups based on the indication for continuous positive airway pressure (CPAP) therapy: five patients received CPAP therapy (group 1) and 19 patients did not (group 2). The patients of group 2 received only a PDE-5 inhibitor (vardenafil 20 mg) for ED; and eight patients (42%) showed an improvement after 3 months of treatment. The five patients receiving CPAP therapy were treated with a combination of parenteral testosterone undecanoate and a PDE-5 inhibitor (vardenafil) and all had normal erectile function after 3 months of therapy. The results suggest positive effects of addition of testosterone to treatment with PDE-5 inhibitors in hypogonadal men with OSAS, which should be confirmed in larger controlled studies.     

The utility of sildenafil citrate for infertile men with sexual dysfunction: a pilot study

OBJECTIVE: To investigate the use the sildenafil citrate, recognized as a first-line therapy for men with erectile dysfunction (ED), and which is safe and effective in men with various causes and severity of ED, including psychogenic ED, in a population of infertile men with sexual dysfunction. PATIENTS AND METHODS: Infertility is a major source of life stress and might be associated with sexual dysfunction through the erosion of self-esteem and self-confidence, and in stimulating discord in a relationship. Men presenting for evaluation of fertility who on questioning by the physician reported the recent onset of sexual dysfunction, had a history taken, a physical examination, hormonal profile, and completed the International Index of Erectile Function (IIEF), a validated inventory for assessing sexual dysfunction. Thirty men with a score of <26 on the erectile function domain of the IIEF, or who complained of new onset rapid or delayed ejaculation, were treated with sildenafil with no randomization or placebo control. The evaluation was repeated and the IIEF completed again > or =3 months after starting treatment. RESULTS: For men complaining of ED, subjective erectile rigidity, duration of erection, and the percentage of successful penetration attempts significantly improved with sildenafil. The mean (sd) IIEF domain scores for erection and satisfaction, at 18 (4) vs 27 (3), and 12 (2) vs 16 (3) (both P = 0.01), and orgasm, at 4 (1) vs 6 (3) (P = 0.001), respectively, significantly improved after treatment. In patients with ejaculatory dysfunction, the function improved in 64% after sildenafil therapy. CONCLUSIONS: We identified the nature of sexual dysfunction associated with male-factor infertility, and showed the efficacy of sildenafil therapy in men with this condition.     

Diagnostic evaluation of erectile dysfunction in the era of oral therapy

Therapy for erectile dysfunction (ED) may be specific to the cause of ED or it may be nonspecific. There are only three causes of ED which have specific therapy: psychogenic, endocrine and certain types of reversible vasculogenic ED. In the era of oral therapy for ED, treatment is not cause-specific in the great majority of patients. For this great majority, only the basic evaluation of ED is needed. Only when there is a strong suspicion that the cause of a patient's ED is endocrine, psychogenic or reversible vascular disease are additional diagnostic tests indicated. In these three categories of patients, specific treatment of the cause of ED can produce a permanent and dramatic improvement in sexual function and satisfaction. International Journal of Impotence Research (2000) 12, Suppl 4, S12-S14.     

Hormonal supplementation and erectile dysfunction

The role of testosterone on sexual desire is well established. However, the effects of low testosterone levels in the pathophysiology of erectile mechanism in humans remains unclear. Recent evidence indicate that approximately 10-20% of men with erectile dysfunction (ED) have hormonal abnormalities, raising up to 35% over the age of sixty. It is now clear that sexual desire and erectile function in humans are both responsive to androgens, probably at different threshold values. In fact, different degrees of testosterone deficiency may determine a sequence of molecular penile events leading to reduced capacity of penile smooth muscle and endothelial cells of relaxation, without greatly affecting sexual desire. Also, androgens may directly control the expression and activity of phosphodiesterase type-5 in human corpus cavernosum. In some selected men with total testosterone below 10-13nmol/l and/or free testosterone below 200-250pmol/l, androgen supplementation may improve therapeutic efficacy of phosphodiesterase type-5 inhibitors. For ageing men with partial androgen deficiency (PADAM) who fail first-line oral treatments in whom androgens are not contraindicated, a combination of testosterone and phosphodiesterase type-5 inhibitors may be considered to improve erectile function and improve the quality of life.     

Testosterone and Erection: Practical Management for the Patient with Erectile Dysfunction

Although erectile dysfunction (ED) and testosterone deficiency syndrome are two independently distributed disorders, there is a degree of overlap between them. Testosterone replacement therapy, either alone or combined with other treatments such as a phosphodiesterase type 5 (PDE5) inhibitor, may therefore be useful in some men with ED. Corrective treatment of ED includes sex therapy, risk factor modification, chronic usage of PDE5 inhibitors, and testosterone replacement. Studies have shown that testosterone replacement in men with hypogonadism improves libido and erectile function in a significant proportion of cases. If corrective treatment fails or is not indicated, symptomatic treatments such as oral PDE5 inhibitors or intraurethral/intracavernous therapy are available. PDE5 inhibitors are an excellent first-line choice, although a significant proportion of men still fail to respond to monotherapy. Testosterone deficiency may be overlooked in some men with ED and, because this may be associated with lower expression of PDE5 in the penis, it could result in failure of PDE5 inhibitor therapy. Recent recommendations, therefore, suggest the need for combination therapy in some patients. In conclusion, all men presenting with ED should have their testosterone levels checked, and testosterone replacement should be considered in those with low levels. Testosterone replacement should also be considered in hypogonadal men with ED not responding to PDE5 inhibitors. If erections remain insufficient after 3 mo, a combination of testosterone and a PDE5 inhibitor may be beneficial.     

从更好的勃起到更好的性生活:万艾可研究进展

万艾可(枸橼酸西地那非)起效快,使患者达到和维持坚硬的勃起,已被证实为首选的勃起功能障碍(ED)治疗药物。近年来,有关万艾可疗效的研究越来越多地关注其对整体性生活的改善,即对患者心理因素的影响。通过应用心理学评价工具,如勃起功能障碍治疗满意度量表、自尊心和性关系问卷、勃起功能障碍心理影响评分等,研究发现万艾可显著改善以下心理性因素:ED患者及其伴侣对性交和性关系的满意度、患者的自信心和自尊心、与伴侣亲近和进行性交的欲望等。服用万艾可的ED患者性交尝试次数显著增加,健康相关的生活质量显著提高。因此,万艾可产生更好的勃起,进一步促进更好的性生活良性循环。