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     

Erectile function and nocturnal penile tumescence in patients with prostate cancer undergoing luteinizing hormone-releasing hormone agonist therapy.

BACKGROUND: Luteinizing hormone-releasing hormone (LHRH) agonists have been widely used as effective agents in endocrine therapy for prostate cancer. Continuous administration of the drug results in profound suppression of testicular androgen production. However, the side effects on erectile function have not been fully investigated. METHODS: We studied the influences of testosterone suppression on male sexual function and nocturnal penile tumescence in nine sexually active patients with prostate cancer who were treated with an LHRH agonist. RESULTS: Following reduction of serum testosterone concentrations to a castration level by the administration of the LHRH agonist, sexual desire, sexual interest and sexual intercourse were totally annulled, with significant changes in frequency, magnitude, duration and rigidity of nocturnal erections observed in all patients. CONCLUSIONS: These results demonstrate that the LHRH agonist strongly suppresses erectile function and sexual activity. Taking into account the quality of sexual function for relatively young and sexually active patients and their partners, it is necessary to establish effective modalities that minimize the adverse effects on sexual function for the treatment of patients with prostate cancer.     

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.     

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.     

Nocturnal tumescence: a parameter for postoperative erectile integrity after nerve sparing radical prostatectomy

PURPOSE: The exact process and time required for rehabilitation of erectile function after nerve sparing prostatectomy remain unclear to date. Different theories of the pathophysiology of postoperative erectile dysfunction are currently being discussed. In a prospective study we performed recordings of nocturnal penile tumescence and rigidity during the acute phase after nerve sparing radical prostatectomy, ie in the first night after removal of the catheter, to assess the organic penile integrity. MATERIALS AND METHODS: In 27 patients with local prostate carcinoma who had been sexually active before the intervention, we performed unilateral or bilateral nerve sparing radical prostatectomy. Preoperative sexual function of all patients was evaluated by the International Index of Erectile Function-5 questionnaire. On the day of catheter removal (postoperative day 7 to 14) an NPTR recording was performed on the following night with an erectometer (RigiScan). RESULTS: All patients had a preoperative IIEF score greater than 18. After removal of the catheter 25 of 27 patients (93%) showed 1 to 5 nocturnal rigidity increases by greater than 70% for at least 10 minutes. In a control group of 4 patients who underwent radical prostatectomy without nerve sparing, no nocturnal erections were recorded. CONCLUSIONS: NPTR recording during the acute phase after nerve sparing radical prostatectomy showed residual erectile function as early as the first night after catheter removal. These results are significant for selecting adequate pharmacological treatment for optimal therapy and rehabilitation of satisfactory erections and sexual function. In cases of early nocturnal tumescence, application of a PDE5 inhibitor can support successive organ rehabilitation. However, if tumescence does not occur, penile injection therapy is recommended.     

Recent insights into androgen action on the anatomical and physiological substrate of penile erection

Erectile response is centrally and peripherally regulated by androgens.The original insights into the mechanismsof action of androgens were that androgens particularly exert effects on libido and that erections in response to eroticstimuli were relatively androgen-independent.It was shown that sexual functions in men required androgen levels atthe low end of reference values of testosterone.So it seemed that testosterone was not useful treatment for men witherectile difficulties,particularly following the advent of the phosphodiesterase type 5(PDE5)inhibitors.However,approximately 50% of those treated with PDE5 inhibitors discontinue their treatment.A number of recent develop-ments shed new light on testosterone treatment of erectile dysfunction(ED)in aging men.(1)A recent insight is that,in contrast to younger men,elderly men might require higher levels of testosterone for normal sexual functioning.(2)Several studies have indicated that PDE5 inhibitors are not always sufficient to restore erectile potency in men,andthat testosterone improves the therapeutical response to PDE5 inhibitors considerably.(3)There is growing insightthat testosterone has profound effects on tissues of the penis involved in the mechanism of erection and that testoster-one deficiency impairs the anatomical and physiological substrate of erectile capacity,reversible upon androgenreplacement.The synthesis of PDE5 is upregulated by androgens,and the arterial inflow into the penis is improved bygiving androgen.The above invites a re-examination of the merits of giving testosterone to aging men with ED.Thebeneficial effects of PDE5 inhibitors may only be optimally expressed in a eugonadal environment.(Asian J Androl2006 Jan;8:3-9)     

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.     

Hypogonadism and erectile dysfunction: pathophysiological observations and therapeutic outcomes

Androgens have a profound effect in male sexual function in general and erectile physiology in particular. Despite the common belief that male sexuality is fully dependent on normal androgens, hypogonadal men are capable of sexual erections; almost a third of men receiving effective antiandrogen therapy can develop erections when tested with an erotic challenge. However, successful hormonal supplementation that results in normal testosterone values does not always restore libido and erectile function. Although the primary goal of treatment for hypogonadism may be to restore sexual function, there will be other significant benefits and potential drawbacks. Libido, general well-being, osteoporosis, muscle strength, mental acuity, and growth hormone levels will all be positively affected by appropriate management of low testosterone levels. Testosterone replacement therapy should maintain not only physiological levels of serum testosterone but also its metabolites, including dihydrotestosterone and oestradiol. The assessment of hypogonadism, its treatment and monitoring, are unavoidable responsibilities of the urologist.     

Oral Agents: First-Line Therapy for Erectile Dysfunction

Oral agents are relatively non-invasive, reversible, readily administered and well tolerated; hence, they are emerging as first-line treatments for patients with erectile dysfunction. Two medications have been licensed in Europe: the dopamine agonist sublingual apomorphine, which influences central regulatory mechanisms, and the phosphodiesterase type 5 (PDE5) inhibitor sildenafil citrate, which affects local regulation of erectile function by potentiating the effects of nitric oxide. Two other potent, selective, reversible PDE5 inhibitors (tadalafil and vardenafil) are under regulatory review in Europe, the United States and other countries. In double-blind, placebo-controlled trials, these compounds significantly enhanced erectile function and increased the likelihood of successful sexual intercourse largely irrespective of etiology or severity of erectile insufficiency. Apomorphine and PDE5 inhibitors also significantly improved scores in the erectile function, orgasmic function, intercourse satisfaction and overall satisfaction domains of the International Index of Erectile Function. Oral agents were well tolerated; adverse events were generally mild or moderate, prompting premature treatment discontinuation in a small minority of patients. The chief adverse effects with apomorphine were nausea and headache, and with PDE5 inhibitors, headache, dyspepsia and flushing. Because of a potential pharmacodynamic interaction between PDE5 inhibitors and nitrates or nitric oxide donors that has been associated with hypotension, concomitant nitrate use is an absolute contraindication. However, the actual incidences of myocardial infarction in sildenafil and tadalafil patients are similar to those in placebo controls.     

The effects of androgen depletion on human erectile function: a prospective study in male-to-female transsexuals

The objective of the study was to determine the effects of androgen depletion on erectile function in a population of male-to-female transsexuals. The erectile function of 25 consecutive male-to-female transsexuals on androgen depletion treatment and scheduled for surgical gender reassignment was prospectively evaluated using medical and sexual history, physical examination, total serum testosterone, International Index of Erectile Function (IIEF-15) questionnaire, penile colour-coded Doppler ultrasonography (CDU) after pharmacological stimulation and nocturnal penile tumescence (NPT) test. All but one had undetectable or low testosterone. Subjective erectile function, according to IIEF-15 scores, and penile CDU findings did not correlate with testosterone levels, whereas NPT test findings correlated well with testosterone levels. These findings would suggest that nocturnal erections are androgen-dependent whereas sexually induced erections are androgen-independent. It can also be assumed that testosterone is important but not essential for male erectile function and that other androgen-independent pathways can be responsible for sexually induced erections.     

Comparison of efficacy and safety of daily oral L-arginine and PDE5Is alone or combination in treating erectile dysfunction: A systematic review and meta-analysis of randomised controlled trials

The meta-analysis was performed to assess the efficacy and safety of daily oral L-arginine and phosphodiesterase type 5 inhibitors (PDE5Is) alone or combination in treating patients with erectile dysfunction (ED). We performed a search of randomised controlled trials in the following databases: PubMed, EMBASE and Cochrane Library databases. Four articles including 373 patients were studied. Erectile functions were significantly improved in three therapy groups compared with baseline. Patients who received the combination of L-arginine and PDE5Is showed significant improvement compared to those treated with L-arginine and PDE5Is alone, as assessed by sexual function index (p <0.00001 and p =0.005, respectively) and total testosterone (p <0.00001 and p =0.0007, respectively). Furthermore, patients who treated with PDE5Is alone exhibited the better efficacy than those treated with L-arginine alone in respects of sexual function index (p <0.00001) and total testosterone (p =0.0001). However, the combination of L-arginine and PDE5Is had no obvious difference relative to PDE5Is alone in terms of various adverse events (AEs). Conclusively, compared with monotherapy, the combination of L-arginine and PDE5Is showed a greater improvement of sexual function and total testosterone, and did not significantly increase the AEs. Besides, PDE5Is alone revealed a better effect than those treated with L-arginine alone for patients with ED.     

Safety and efficacy of vardenafil in patients with erectile dysfunction: Result of a bridging study in Japan

AIM: Vardenafil is a selective and highly potent phosphodiesterase type 5 (PDE5) inhibitor for the treatment of erectile dysfunction (ED), with improved selectivity for PDE5 and demonstrated efficacy for improving sexual function in men with ED. The current study investigated the safety and efficacy of this new PDE5 inhibitor in Japanese men with ED. METHODS: This was a prospective, double blind, randomized clinical trial designed to evaluate the efficacy and safety of vardenafil. Following a 4-week treatment-free observation period, 283 eligible patients were randomized to 12 weeks treatment with vardenafil 5 mg, 10 mg, 20 mg, or placebo. Primary efficacy responses were assessed using the scores of Q3 and Q4 of the international index of erectile function (IIEF). RESULTS: All three vardenafil doses showed significantly better improvement than the placebo group in Q3 and Q4 scores of the IIEF questionnaire, either at 12 weeks or at the 'last observation carried forward' (LOCF, P < 0.0001). Q3 scores were improved to 4.06 with vardenafil 5 mg, 4.53 with vardenafil 10 mg, and 4.64 with vardenafil 20 mg, versus 3.17 with placebo. Comparable scores for Q4 were 3.47, 4.15 and 4.31 versus 2.31 for placebo. Up to 86% of patients achieved improved erections as assessed by the global assessment question (GAQ). Reported adverse event rates were 35.3%, 45.3% and 54.5% with vardenafil 5 mg, 10 mg and 20 mg, respectively, versus 21.1% in the placebo group. No serious adverse drug reactions were reported. The most common treatment-emergent adverse events were transient headache, flushing and rhinitis, which were mostly mild. CONCLUSION: Vardenafil is an effective and well-tolerated treatment for ED and provides improvement in key indices of erectile function among Japanese men with ED. The results of our trial show that up to nearly 90% of patients achieve improved erections with the administration of vardenafil.     

Die nerverhaltende radikale retropubische Prostatektomie Ergebnisse nach Patientenbefragung

Improved selection criteria have led to an increasing number of nerve-sparing radical retropubic prostatectomies (RRP) in patients with clinically localized prostate cancer. The results based on patient questionnaires regarding postoperative erectile function are described. Between January 1992 and March 1999, 366 patients (mean age: 62.5 years) underwent uni- or bilateral nerve-sparing RRP at our institution. For evaluation of postoperative patient-reported rates of sexual and erectile function, a questionnaire was used after a follow-up of at least 12 months. Data of five operation periods were analyzed. The results of the unilateral procedure for the five operation periods revealed consistent rates of 13-29% for erections sufficient for intercourse. Bilateral nerve-sparing procedures were almost exclusively performed in periods 3 to 5; only four patients from period 2 underwent the bilateral procedure. The rates of intercourse-sufficient erections were 25% (period 2), 61% (period 3), 50% (period 4), and 52% (period 5), respectively. The results of the unilateral procedure were disappointing. However, the bilateral nerve-sparing method achieved much better results inasmuch as about 50% of the patients reported recovery of erections sufficient for sexual intercourse.     

Phosphodiesterase type 5 inhibitors for erectile dysfunction

The cyclic nucleotide signalling pathway mediates the smooth-muscle relaxing effects of nitric oxide necessary for normal erectile function. Down-regulation of this pathway is central to the pathophysiology of many forms of erectile dysfunction (ED), which is often associated with other chronic diseases (e.g. hypertension, type 2 diabetes mellitus) and treatments (e.g. certain drugs, radical prostatectomy). Conversely, selective inhibition of the enzyme that catalyses the degradation of cGMP (phosphodiesterase type 5, PDE-5) promotes erectile responses to sexual stimulation. The successful launch and commercialization of the selective PDE5 inhibitor (PDE5I) sildenafil transformed the treatment of ED, not only by providing an effective, well tolerated oral ED therapy, but also by fostering greater candour about the problem among men. Sildenafil is highly effective in promoting erectile responses across a wide spectrum of severity and causes of ED, including patients with ED that is often refractory to treatment. The recent advent of vardenafil, which has the highest in vitro potency of all available PDE5Is, and tadalafil, which has a prolonged half-life that may enable couples to have sexual activity with less planning, represent further advances. Other PDE5Is offering further potential improvements are under active investigation.     

Testosterone levels in men with erectile dysfunction

OBJECTIVE: To investigate the frequency of hypogonadism in men with erectile dysfunction (ED) and to assess which factors are related with low testosterone levels. PATIENTS AND METHODS: In all, 165 men with ED were assessed; the evaluation included: hormonal profiles, serum total and free testosterone (using Vermeulen's formula) levels, and self-reported questionnaires on erectile function and desire domains of the International Index of Erectile Function. The frequency of hypogonadism was established using total and free testosterone levels as diagnostic criteria. The factors that might influence testosterone levels were evaluated by univariate and multivariate statistical analysis, and a logistic regression was used to determine which factors can predict free testosterone levels below normal limits (biochemical hypogonadism). RESULTS: Using the total testosterone levels, 4.8% of the men were hypogonadal, whereas when using the free testosterone levels, 17.6% were hypogonadal. In the univariate analyses, not smoking and hypertension were associated with lower total and free testosterone levels. Ageing, absence of nocturnal erections and a lower erectile function score were only associated with lower free testosterone serum levels. There was no association between total and free testosterone levels and desire. In the multivariate analysis, only total testosterone levels were related to hypertension, while free testosterone levels were related to age and nocturnal erections. For biochemical hypogonadism, simple logistic regression analysis selected age, erectile function score and aetiological diagnosis of ED as predictors. In the multivariate analysis only the erectile function score had significant independent prognostic value. CONCLUSIONS: The frequency of hypogonadism is higher when free testosterone levels are used for diagnosis. The total and free testosterone levels were not related to the level of sexual desire in men with ED. The free testosterone levels could be related to the quality and frequency of nocturnal erections, and when ED is more severe, it is more probable that free testosterone levels are below the 'normal' limit.     

Long-term efficacy and safety of oral Viagra (sildenafil citrate) in men with erectile dysfunction and the effect of randomised treatment withdrawal

The long-term efficacy and safety of oral Viagra (sildenafil citrate), a selective phosphodiesterase 5 inhibitor, and the effect of withdrawing treatment were evaluated in men with erectile dysfunction (ED). In 233 men with ED of psychogenic or mixed organic/psychogenic aetiology, 16 weeks of open-label, flexible-dose sildenafil treatment (10-100 mg) was followed by eight weeks of double-blind, fixed-dose, randomised withdrawal to placebo or continued treatment with sildenafil. Sildenafil was taken as needed (not more than once daily) approximately 1 h prior to sexual activity. The main outcome measures were a global efficacy question, a sexual function questionnaire, an event log of erections, and adverse event recording. In the open-label phase, 200 of 216 patients (93%) reported improved erections with sildenafil; 28 patients (12%) discontinued treatment. In the double-blind phase, the significant improvements in the frequency and duration of erections were maintained in the sildenafil group but returned to pre-treatment values in patients on placebo (P values < 0.0001 versus placebo). The most frequent adverse events in the sildenafil group during the double-blind phase were flushing (7%), headache (6%), and dyspepsia (5%). Of the 192 patients enrolled in the 1-y extension, 90% completed the study; only two patients (1%) were withdrawn due to lack of efficacy. In men with ED of psychogenic or mixed aetiology, oral sildenafil is effective and well-tolerated both at the initiation of therapy and during long-term treatment. For most patients, sildenafil treatment must be continued for improvements in erectile function to be maintained.     

Recreational use of erectile dysfunction medication may decrease confidence in ability to gain and hold erections in young males

We aimed to estimate the frequency of recreational use of erectile dysfunction medication (EDM) and to identify any adverse effects on confidence in gaining and holding erections resulting from such use. In addition, we explored differences in erectile function and sexual behavior between recreational and medicinal users of EDM to control for the possibility of recreational users having but not admitting erectile dysfunction. A subset from the Genetics of Sex and Aggression population-based sample of 4428 males with a mean age of 29.51 (s.d.=6.77) years provided information on their use of EDM, erectile function during first intercourse and currently, sexual behavior and confidence in their ability to gain and hold erections. There were 2.6% (n=115) recreational and 0.9% (n=39) medicinal users of EDM. Recreational users had currently significantly lower confidence in their erectile ability than non-users even though they had significantly better erectile function and significantly more unrestricted sexual behavior as well as had more confidence when initiating sexual activity. More frequent use of EDM was associated with significantly less confidence in erectile ability among the recreational users. We conclude that recreational users of EDM may be vulnerable for becoming psychologically dependent on pharmacologically induced erection.     

Patient-reported sexual function after nerve-sparing radical retropubic prostatectomy

OBJECTIVE: Improved selection criteria have lead to an increasing number of nerve-sparing radical retropubic prostatectomies (RRP) in patients with clinically localised prostate cancer (PCA). Patient questionnaire based outcome analysis on post-operative erectile function after uni- or bilateral nerve-sparing RRP is described. METHODS: Between January 1992 and March 1999, 366 patients (mean age 62.5 years) underwent uni- or bilateral nerve-sparing RRP at our institution. Indication for nerve-sparing procedure was based on the results of a multivariate classification and regression tree analysis (CART). For evaluation of post-operative patient-reported rates of sexual and erectile function non-validated and validated questionnaires (IIEF 5) were administered after a follow-up of 12 months. Data of five operation periods were analysed. RESULTS: The unilateral procedure resulted in rates of 13-29% of erections sufficient for unassisted intercourse. Some degree of tumescence was reported by 37-73% of the remaining patients. Bilateral nerve-sparing procedures were almost exclusively performed in periods 3-5, only four patients of period 2 received the bilateral procedure. Here, rates of erections sufficient for intercourse were 25% (period 2), 61% (period 3), 50% (period 4), and 52% (period 5), respectively. Patients with grades 4 and 5 erections had IIEF scores of 19.2 and 20.2 and patients without rigidity or tumescence had scores of 5.7 and 7.0 after uni- and bilateral nerve-sparing procedure, respectively. Patients <60 years of age had better erections than those > or =60 (unilateral: 19% versus 13%, bilateral 45% versus 38%). CONCLUSION: Compared to a unilateral nerve-sparing procedure, the bilateral nerve-sparing technique revealed much better results inasmuch as about 50% of the patients reported recovery of erections sufficient for sexual intercourse without use of sexual aids.     

Vardenafil: A new approach to the treatment of erectile dysfunction

Vardenafil is a phosphodiesterase type-5 (PDE-5) inhibitor developed as an oral therapy for erectile dysfunction (ED). Multiple phase 3 clinical trials have been completed and vardenafil is expected to launch worldwide in 2003. Two pivotal, randomized, double-blind, multicenter studies have evaluated the use of vardenafil in men with ED. Vardenafil improved the rate of achieving and maintaining an erection during sexual intercourse. Improvement also was noted in other aspects of sexual function, including confidence, orgasmic function, and overall satisfaction. Vardenafil produces clinically and statistically significant improvements in erectile function regardless of age, baseline severity, and etiology and is efficacious for the treatment of ED in diabetic and postprostatectomy patients. Vardenafil has a rapid onset of action and completion of successful sexual intercourse is possible for some patients 16 minutes after its administration. Twenty milligrams of vardenafil has sustained long-term efficacy by providing up to 92% of patients with improved erections during more than 2 years of treatment. Vardenafil is well tolerated, with an adverse event profile typical of the class of PDE-5 inhibitors. The most common adverse events were headache, flushing, rhinitis, and dyspepsia, which were mild or moderate and generally decreased with continued treatment. Vardenafil may be associated with transient reductions in blood pressure and commensurate increases in heart rate, with the overall incidence of cardiovascular-related adverse events similar to that of placebo.     

Current approaches to erectile dysfunction and testosterone deficiency

Androgens are essential for the development of the penis and it is well known that testosterone play a critical role in the physiology of erectile function. From animal studies, testosterone insufficiency disrupts cellular-signaling pathways and induces pathologic alterations in penile tissues leading to erectile dysfunction. In human, the testosterone threshold for maintaining erection is low which explains the reason why some contracted men still have an erection due to the androgens produced by the adrenal gland. Testosterone alone can improve erectile function in hypogonadic patients. Associated with PDE5-I, testosterone supplementation is a treatment for the hypogonadic patients non responders to therapy. The article reviews the different aspects of the testosterone role in the pathophysiology of erection.