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.     

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.     

YOHIMBINE FOR ERECTILE DYSFUNCTION: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED CLINICAL TRIALS

Purpose

Erectile dysfunction is a common problem, particularly in diabetics. It is associated with a considerable burden of suffering. No generally accepted drug treatment exists. We systematically reviewed and meta-analyzed all randomized, placebo controlled trials of yohimbine monotherapy for erectile dysfunction to determine its therapeutic efficacy. Our secondary aim was to evaluate the safety of yohimbine.

Materials and Methods

We used computerized literature searches and standardized data extraction to rate methodological quality in a meta-analysis using computer statistical software.

Results

Seven trials fit the predefined inclusion criteria. Overall methodological quality of these studies was satisfactory. The meta-analysis demonstrated that yohimbine is superior to placebo in the treatment of erectile dysfunction (odds ratio 3.85, 95% confidence interval 6.67 to 2.22). Serious adverse reactions were infrequent and reversible.

Conclusions

The benefit of yohimbine medication for erectile dysfunction seems to outweigh its risks. Therefore, yohimbine is believed to be a reasonable therapeutic option for erectile dysfunction that should be considered as initial pharmacological intervention.     

Hyperprolactinaemia due to hypothalamic-pituitary disease or drug-induced in patients with erectile dysfunction

One hundred and sixty-five patients with erectile dysfunction were assessed at the Athens Medical Sex Institute: 60 men (36.4%) considered their condition as organic, 52 (31.5%) rated it as mostly psychogenic, 45 (27.2%) thought it could be of mixed aetiology and 8 (4.8%) could not comment at all as to the aetiology. Initial psychologic evaluation rated the condition in the majority of cases as psychogenic (130 patients, 84.8%). No psychologist considered the erectile dysfunction as purely (100%) organic. After the urological and endocrine evaluation, vascular disorder was considered in 30 patients (18.2%), endocrine dysfunction in 16 patients (9.7%) and psychogenic in 109 patients (66.1%). Sixteen of the above patients had definite hyperprolactinaemia, two had large-sized prolactinomas as revealed by magnetic resonance imaging (MRI) and pituitary function tests. Four had nonfunctioning pituitary tumours, which was also based on MRI and pituitary tests. Four had small prolactin (PRL) adenomas. Drug-induced hyperprolactinaemia was suspected in six patients who used medications affecting PRL secretion and had no evidence of tumour on radiological evaluation. In conclusion, hyperprolactinaemia in men with erectile dysfunction needs to be evaluated before considering any other treatment.     

Acupuncture in the treatment of psychogenic erectile dysfunction: first results of a prospective randomized placebo-controlled study

In a prospective study, we investigated the potentially curative effect of acupuncture in patients with psychogenic erectile dysfunction (pED). A total of 22 patients with pED were randomized into two groups. They were either treated with acupuncture specific against ED (treatment group) or acupuncture specific against headache (placebo group). Nonresponders of the placebo group were crossed over to the treatment group. Prior to acupuncture, serum sexual hormone levels, IIEF score, nocturnal penile tumescence testing for three nights (Rigiscan) and the erectile response to 50 mg sildenafil were evaluated. Out of 21 patients, 20 completed the study, including 10 patients after crossover. A satisfactory response was achieved in 68.4% of the treatment group and in 9% of the placebo group (P=0.0017). Another 21.05% of the patients had improved erections, that is, sufficient rigidity under simultaneous treatment with 50 gm sildenafil. The results of our pilot study indicate that acupuncture can be an effective treatment option in more than two-thirds of patients with psychogenic erectile dysfunction.     

Multicentral clinical evaluation of the aetiology of erectile dysfunction: A survey report

Patients with erectile dysfunction, who admitted to 4 different urological centres in Turkey were evaluated in terms of aetiological factors to establish the aetiology of erectile dysfunction in our population and compare it with the data derived from Western communities. After the history, physical examination, psychological evaluation and laboratory testing, a clinical diagnosis was established as primarily psychogenic, organic, or mixed aetiology. Mean patient age was 43.5 years (range 17 to 69), and 9 of the patients were unmarried. Of the patients 53 had vascular risk factors, and 10 reported a history of alcohol abuse. Eleven patients were using drugs that might interfere with the disorder. In this multicentral study of 115 impotent men, an organic cause was found in 43%, psychogenic in 47%, and mixed in 19%. Mean age of the overall patients was 43.48. When the ages of the patients with organic erectile dysfunction and those with psychogenic erectile dysfunction were compared, it was clearly seen that those with organic erectile dysfunction were much older (52.73 versus 33.02). This revised version was published online in June 2006 with corrections to the Cover Date.     

New concept parameters of RigiScan in differentiation of vascular erectile dysfunction: Is it a useful test?

BACKGROUND: The aim of this study is to investigate the value of new nocturnal penile tumescence recording parameters, such as tumescence activity unit and rigidity activity unit values, total erection number and erection times, in differentiating between psychogenic erectile dysfunction and organic erectile dysfunction. We also aimed to determine the role of these parameters in differentiating arterial erectile dysfunction from veno-occlusive dysfunction. METHODS: Eighty-seven consecutive patients were allocated into three groups as psychogenic, arterial and venous erectile dysfunction after investigations. Nocturnal penile tumescence recording parameters between psychogenic and vascular erectile dysfunction and arterial and veno-occlusive dysfunction were compared. Mann-Whitney U-test, Pearson's chi2 test and correlation coefficient tests were used for statistical analysis. RESULTS: Depending on intracavernous injection, penile Doppler ultrasonography and cavernosometry tests, 37 patients (43%) had psychogenic impotence while 50 (57%) had organic pathologies. Of the 50 patients diagnosed with vascular impotence, 29 (48%) had arterial failure and 21 (42%) had veno-occlusive dysfunction. Nocturnal penile tumescence recording revealed psychogenic erectile dysfunction in 34 patients (39%) and vascular erectile dysfunction in 53 patients (61%). Nocturnal penile tumescence recording has been regarded as the gold standard and, in our series, it showed 90.6% sensitivity and 88.2% specificity in differentiating the cause of erectile dysfunction. Values of rigidity activity unit and tumescence activity unit were significantly higher in patients with psychogenic impotence (P < 0.001), when compared with vascular impotence. In patients with a vascular cause, no difference was found between arterial failure and veno-occlusive dysfunction with regard to tip tumescence activity unit, base tumescence activity unit, tip rigidity activity unit, base rigidity activity unit and erection time (P > 0.001). However, patients with arterial failure had less erection than patients with veno-occlusive dysfunction (P < 0.001). CONCLUSION: New recording parameters of nocturnal penile tumescence can differentiate organic and psychogenic erectile dysfunction more precisely. However, these recording parameters cannot distinguish subgroups with a vascular cause of erectile dysfunction.     

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.     

Can the International Index of Erectile Function distinguish between organic and psychogenic erectile function?

OBJECTIVE

To define the ability of the International Index of Erectile Function (IIEF) to differentiate between organic and psychogenic erectile dysfunction (ED).

PATIENTS AND METHODS

Patients presenting for the evaluation and treatment of ED who had penile duplex Doppler ultrasonography (DUS) completed the IIEF questionnaire. Accepted ranges of the IIEF EF domain were used to grade baseline severity (severe, moderate and mild ≤11, 11–17, 18–25, respectively). Accepted criteria were used to define normality on DUS (peak systolic velocity >30 cm/s and end‐diastolic velocity <5 cm/s). Patients with documented Peyronie’s disease, hypogonadism and a history of radical prostatectomy were excluded.

RESULTS

In all, 112 patients were enrolled, with a mean (sd ) age and duration of ED of 56 (16) and 2 (0.6) years, respectively. The vascular risk‐factor profile included diabetes in 15%, hypertension in 26% and hyperlipidaemia in 20%. The baseline severity of ED was mild, moderate and severe in 28%, 41% and 32% men, respectively. All patients had normal testosterone levels. Patients also with a normal DUS were diagnosed with psychogenic ED, in 50%, 13% and 17% of men with mild, moderate and severe ED by the IIEF, respectively. No patient with venous leak had mild ED, and 62% of men with venous leak had severe ED.

CONCLUSIONS

These results indicate that the IIEF is not completely accurate in differentiating between organic and psychogenic ED, and that almost a fifth of men in this study population with severe ED by the IIEF had normal erectile haemodynamics. These data have potential ramifications for evaluating the baseline severity of ED in trials of erectogenic agents.     

Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II

We review our experience with Melanotan II, a non-selective melanocortin receptor agonist, in human subjects with erectile dysfunction (ED). Melanotan II was administered to 20 men with psychogenic and organic ED using a double-blind placebo-controlled crossover design. Penile rigidity was monitored for 6 h using RigiScan. Level of sexual desire and side effects were reported with a questionnaire. In the absence of sexual stimulation, Melanotan II led to penile erection in 17 of 20 men. Subjects experienced a mean of 41 min Rigiscan tip rigidity>80%. Increased sexual desire was reported after 13/19 (68%) doses of Melanotan II vs 4/21 (19%) of placebo (P<0.01). Nausea and yawning were frequently reported side effects due to Melanotan II; at a dose of 0.025 mg/kg, 12.9% of subjects had severe nausea. We conclude that Melanotan II is a potent initiator of penile erection in men with erectile dysfunction. Our findings warrant further investigation of melanocortin agonists and antagonists on penile erection. International Journal of Impotence Research (2000) 12, Suppl 4, S74-S79.     

Can simvastatin improve erectile function and health‐related quality of life in men aged >40 years with erectile dysfunction? Rationale and design of the Erectile Dysfunction and Statins (EDS) Trial [ISRCTN66772971]1

What’s known on the subject? and What will the study add? Erectile dysfunction is often associated with endothelial dysfunction. It is also recognized as a marker for underlying vascular disease. This study tests the hypothesis that statin therapy may improve erectile function and also reduce the risk of future cardiovascular events via a reduction in serum cholesterol and by improving endothelial function. The study will also determine whether the treatment improves quality of life related to sexual function.

OBJECTIVE

? To describe the rationale and design of the Erectile Dysfunction and Statins (EDS) Trial which aims to evaluate the effectiveness of simvastatin on erectile function and health‐related quality of life in men aged ≥40 years with erectile dysfunction.

PATIENTS AND METHODS

? The study is a randomized, double‐blind, placebo‐controlled trial to test the hypotheses that statins improve endothelial function and reduce cholesterol and may improve erectile function in men with untreated erectile dysfunction (ED). ? Study subjects are men ≥40 years who are not receiving lipid‐lowering or anti‐hypertensive medication and have no other cardiovascular disease (CVD) risk factors. ? Eligible men with untreated ED are randomized to double‐blind treatment with 40 mg simvastatin or placebo once daily for 6 months. ? Data are collected at baseline, mid‐trial and at the final follow‐up visit at 30 weeks. ? The main outcome is erectile function measured by the five‐item version of the International Index of Erectile Function. Secondary outcomes include sexual‐health‐related quality of life and endothelial function.

RESULTS

? Ten general practices have been recruited in the east of England. ? We have randomized 173 men for a power of 90% to assess the main outcome. ? To date there have been no serious unexpected adverse events. ? Study findings will be available in September 2011.

CONCLUSION

? If simvastatin improves erectile function it would provide an inexpensive treatment for ED suitable for most men, and reduce the risk of future CVD.     

Trazodone for erectile dysfunction: a systematic review and meta-analysis

OBJECTIVE: To determine the efficacy and safety of trazodone in the treatment of erectile dysfunction (ED) in a meta-analysis. METHODS: The data sources used were Medline and the Cochrane Library databases (January 1966 to May 2002), bibliographies of retrieved articles and review articles, and conference proceedings and abstracts. Trials were eligible for inclusion in the review if they included men with ED, compared trazodone with a control, were randomized, of > or = 7 days' duration and assessed clinically relevant outcomes. Two reviewers independently evaluated study quality and extracted data in a standardized fashion. RESULTS: Six trials (comprising 396 men) met the inclusion criteria; they consisted of heterogeneous populations, were small, brief and in some cases methodologically weak. Three of the six trials showed an apparently clinically meaningful benefit of trazodone for ED compared with placebo, the differences being statistically significant in two. In pooled results, trazodone monotherapy appeared more likely than placebo to lead to a 'positive treatment response', although this difference was not statistically significant (37% vs 20%; relative benefit increase, 1.6; 95% confidence interval, CI, 0.8-3.3). Subgroup analyses suggested that men with psychogenic ED might be more likely to benefit from trazodone than those with mixed or physiological ED. The efficacy of trazodone also appeared greater at higher doses (150-200 vs 50 mg/day). Men randomized to trazodone were not significantly more likely than those receiving placebo to withdraw for any reason or for an adverse event, or to have specific adverse events, but wide CIs could not exclude a greater risk of these adverse outcomes with trazodone. Specific adverse events with trazodone included dry mouth (19%), sedation (16%), dizziness (16%) and fatigue (15%). CONCLUSION: Trazodone may be helpful in men with ED, possibly more so at higher doses, and in men with psychogenic ED. Future high-quality trials should compare trazodone with placebo and other therapies in men with depression and psychogenic ED.     

Is sildenafil failure in men after radical retropubic prostatectomy (RRP) due to arterial disease? Penile duplex Doppler findings in 174 men after RRP

Sildenafil is frequently the first-line treatment for post-radical retropubic prostatectomy (RRP) erectile dysfunction (ED) with maximum treatment satisfaction rates of 43%-80%. The etiology of erectile dysfunction after RRP has been attributed to psychogenic, vascular, veno- occlusive or nerve injury causes. The purpose of this study was to gain insight into the penile duplex Doppler arterial parameters in men with ED after RRP who failed sildenafil. The purpose was to assess whether sildenafil failure after RRP is associated with underlying corporal arterial disease. A total of 174 consecutive men presenting with sildenafil refractory ED after nerve-sparing RRP underwent color duplex penile Doppler evaluation with vasoactive injection. Mean age was 59.6 y and mean time from surgery was 11.6 months. Some 81% (141/174) of the men had no pre-operative ED (PED). Significant differences in penile duplex Doppler parameters for arterial disease were seen between men with and without PED. In men without PED, 19% (27/141) manifested arterial insufficiency. However, in men with PED, 50% (16/33) demonstrated arterial disease. Nerve sparing status did not affect the presence of arterial disease. Sildenafil refractory erectile dysfunction after RRP in men without PED is not predominantly associated with penile Doppler parameters consistent with arterial insufficiency.     

The effect of simvastatin in penile erection: a randomized, double-blind, placebo-controlled clinical trial (Simvastatin treatment for erectile dysfunction-STED TRIAL)

The aim of the study is to evaluate the effect of simvastatin in erectile dysfunction (ED) secondary to endothelial dysfunction. This study is a double-blind, randomized, placebo-controlled, clinical trial in patients with ED and endothelial dysfunction. Patients were randomized to receive 20 mg simvastatin (n = 21) or placebo (n = 20) daily for 6 months and subsequently 10 mg of vardenafil on demand for 4 weeks. Serum cholesterol, hormone profile, ultrasensitive C-reactive protein, the International Index of Erectile Dysfunction (IIEF) and the ED Index of Treatment Satisfaction were evaluated. There was a significant reduction in serum cholesterol in the treatment group. The hormonal profile remained unaltered. There was no difference in the IIEF between the groups at follow-up, although, at the beginning, 26% of the patients of both groups presented with mild ED and 74% with moderate-to-severe ED; at the end of the 7th month, all patients from the simvastatin group progressed to mild ED, compared with only 83% in the placebo group. There was no statistically significant difference in penile erection after intake of simvastatin or placebo. This study does not support the use of simvastatin as erectogenic medication. Further studies are necessary to verify if simvastatin has any beneficial effect on ED.     

The efficacy, safety and tolerability of intracavernous PNU-83757 for the treatment of erectile dysfunction

PURPOSE: Despite the introduction of sildenafil citrate many men with erectile dysfunction remain dependent on intracavernous therapy. While the majority achieves satisfactory results with currently available intracavernous preparations, all preparations have undesirable side effects, including priapism, fibrosis and post-injection pain. We determined the efficacy, safety and tolerability of the erectogenic potassium channel opener PNU-83757. MATERIALS AND METHODS: We selected 66 men with erectile dysfunction of vascular etiology for intracavernous injection of PNU-83757 in a single dose, single blind, placebo controlled study. Of the 6 patients allocated into each of 11 dose groups 5 received active drug and 1 received placebo. Groups received progressive doses of PNU-83757 or placebo. Holter monitoring was performed at scheduled intervals. Heart rate, and systolic, diastolic and mean blood pressure were assessed at scheduled intervals. Blood samples were obtained for pharmacokinetic study. Patients were evaluated at regular intervals for adverse events. Investigators and patients evaluated efficacy. RESULTS: The first complete erection was observed at 10 mcg. Of the 25 patients receiving active drug in the 60 to 140 mcg. groups only 1 had no erectile response, 15 had partial erection and 9 had complete erection. No serious adverse events or cardiovascular effects were noted. CONCLUSIONS: The minimum effective dose for complete erection was 10 mcg. The erectile response reached a plateau between 60 and 140 mcg., suggesting minimal improvement in efficacy at higher doses. Patient evaluation of erectile quality corresponded well with that of investigators. PNU-83757 was efficacious and extremely well tolerated, and the only adverse events were mild. No cardiovascular side effects were observed at any dose. PNU-83757 intracavernous injections caused no post-injection pain in any patient, which may make PNU-83757 superior to alprostadil in a select group. Further study is required to evaluate the efficacy of PNU-83757 combined with other drugs and with sexual stimulation.     

Asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and L-arginine in patients with arteriogenic and non-arteriogenic erectile dysfunction

The plasma concentration of asymmetrical dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, has been linked to endothelial dysfunction. We investigated the relation between ADMA, symmetric dimethylarginine (SDMA) and L-arginine concentrations and erectile dysfunction. We compared plasma levels of ADMA, SDMA and L-arginine in 61 men in good health with erectile dysfunction of arteriogenic and non-arteriogenic origin. Diagnosis of erectile dysfunction was based on the International Index of Erectile Function Score and its aetiology was classified with penile echo-colour-Doppler in basal condition and after intracavernous injection of prostaglandin E1. The ADMA and SDMA concentrations were significantly higher in men with arteriogenic erectile dysfunction compared with those with erectile dysfunction of non-arteriogenic origin (p??0.05) nor between each of the two erectile dysfunction subgroups and controls (p?>?0.05). The L-arginine/ADMA and the L-arginine/SDMA ratios in arteriogenic erectile dysfunction subgroups were significantly lower than both in controls (p??0.05). We conclude that ADMA and SDMA concentrations are significantly higher and L-arginine/ADMA ratio lower in patients who have arteriogenic erectile dysfunction compared with both patients with non-arteriogenic erectile dysfunction and controls. The negative correlation between ADMA and severity of erectile dysfunction is present only in patients with arteriogenic erectile dysfunction. This study supports the importance to always distinguish arteriogenic from non-arteriogenic erectile dysfunction patients to study the complicate erectogenic mechanisms that lead to erectile dysfunction and also to provide potential therapeutic agents for patients with arteriogenic erectile dysfunction.     

The Role of Apomorphine SL in the Treatment of Erectile Dysfunction

Epidemiological data indicate that erectile dysfunction (ED) affects over 140 million men worldwide, with the highest prevalence in men over 60 years. While the condition is often associated with coronary artery disease, hyperlipidemia, hypertension and diabetes, and may be a marker for these conditions, most men who present with ED for treatment have mild to moderate dysfunction. Treatment guidelines developed by an international, multidisciplinary panel of experts as a “process of care model for erectile dysfunction” recommend the implementation of oral agents as first-line therapy. Sublingual apomorphine SL is the first medication for the treatment of erectile dysfunction with a central mechanism of action. In clinical studies, apomorphine SL provides clinical erectogenic benefits at 2 and 3 mg doses particularly in those patients with mild to moderate ED. Apomorphine SL has the added advantages of a rapid onset of action, resulting in erection in less than half the time required by sildenafil, and a highly favorable tolerability and safety profile, especially in patients with coronary artery disease receiving nitrates. Apomorphine SL is an important addition to the armamentarium of primary care clinicians and urologists treating male erectile dysfunction, due to enhanced erectile function, speed of onset, convenience of dosing, and favorable side effect profile. Apomorphine SL 2 and 3 mg is an effective first-line treatment option for men presenting with mild to moderate ED, who have a degree of residual erectile function that is inadequate for satisfactory sexual performance.     

Is yohimbine effective in the treatment of organic impotence? Results of a controlled trial

Yohimbine is an alpha-adrenoceptor blocker that has been used in the treatment of erectile dysfunction. Adequate trials of this substance in a clearly defined organically impotent population are not available. We conducted a randomized, controlled study with partial cross-over of yohimbine versus placebo in 100 organically impotent men. The first phase of the study showed a positive response in 42.6 per cent of the patients receiving yohimbine versus 27.6 per cent in the placebo group. Although favorable to the test medication these values did not reach statistical significance (p equals 0.42). A similar pattern was noted in the second phase of the study. The over-all response rate of 43.5 per cent was consistent with a previous noncontrolled trial but it was much lower than previous studies. The response rate of organically impotent patients to yohimbine is at best marginal. Owing to its ease of administration, safety and modest effect it still is used in those patients who do not accept more invasive methods. Adrenoceptors are involved in the erectile process, although other neurotransmitter systems also are putative modulators of penile erection, including cholinergic, dopaminergic and vasoactive intestinal polypeptide pathways. It is beyond reasonable expectation that a single agent be of value for all cases of organic impotence. However, yohimbine has shown modest effectiveness at the doses used in this trial (18 mg. per day). Higher doses or a different route of administration may produce different effects.     

Value of prostaglandin El in the diagnosis of erectile dysfunction in comparison with papaverine and papaverine/phentolamine in 61 patients with erectile dysfunction

In 61 patients with erectile dysfunction a comparative study with intracavernous injection of prostaglandin E1 (PGE1), papaverine and a mixture of papaverine and phentolamine was performed. All patients underwent comprehensive multidisciplinary examinations, including bulbocavernosus reflex (BCR) latencies and somatosensory evoked potentials, penile Doppler sonography, dynamic or pharmaco-cavernosonography, and for 11 patients nocturnal penile tumescence (NPT) was also recorded with the Rigiscan. This diagnostic approach suggested that in 24 (39.3%) of the 61 pts the etiology was psychogenic and in the remaining 37 (60.7%) it was organogenic. PGE1 had a much higher erectile potency than papaverine and a somewhat higher potency than the mixture of papaverine and phentolamine. Complete erection was achieved in 41 of the 61 patients (67.2%) with PGE1, as against 20 of the 61 patients (32.8%) with papaverine alone and 20 of the 61 (32.8%) with papaverine/phentolamine. Whereas 7 of 61 patients (11.5%) had priapism of more than 6 h duration and requiring therapy after injection of papaverine or papaverine/phentolamine, no priapism occurred after PGE1. Thus, compared with papaverine and phentolamine, PGE1 offers important advantages in the diagnosis and perhaps also in the therapy of erectile dysfunction.