The efficacy of sildenafil citrate (Viagra) in clinical populations: an update

Sexual attitude and perception on sexual relationship among long-term users of sildenafil

INTRODUCTION

High discontinuation rates of sildenafil were reported in its responders.

AIM

To investigate perception on and attitude toward sex among long-term users of sildenafil.

METHODS

A survey was conducted using random face-to-face interviews and a structured questionnaire on a population of 105 long-term sildenafil users (mean age; 57.8 years), who first took sildenafil 5 years or more previously and continued its use in the previous 6 months.

MAIN OUTCOME MEASURES

Six point-scale of perception on and attitude toward sex and valuation of sildenafil.

RESULTS

Among the long-term users, 98% perceived that it is desirable to have sex even though they get old if they are healthy, 93% had a positive attitude toward sex, and 97% had an intercourse-focused perception of sexual relationship; these rates were higher for those with a lower income and less education. And 59% had intercourses and 40% took sildenafil one to two times a week. They ranked prominence in rigidity of erection as the major reason for the long-term sildenafil use. The rigidity was maintained after more than 5-year use.

CONCLUSION

An overall majority of the long-term users of sildenafil had a positive attitude toward sex, an active sexual behavior, and an intercourse-focused perception on sexual relationship. Sildenafil provided an optimal fit for the patients' needs. Prominence in rigidity of erection was ranked as the major reason for the long-term use.

Cardiovascular outcomes among sildenafil users: results of the International Men's Health Study

AIM

To assess the incidence of serious cardiovascular disease (CVD) events [i.e. myocardial infarction (MI) and stroke] and all-cause mortality in men with erectile dysfunction (ED) who received prescriptions for sildenafil.

METHODS

The International Men's Health Study (IMHS) was a prospective, observational cohort study of patients with ED and a new or existing prescription for sildenafil. Baseline and follow-up questionnaires provided information on demographics, CVD risk factors and ED. Postevent questionnaires were mailed to patients following possible nonfatal CVD events to collect information related to exposure to sildenafil/ED treatments before the event.

RESULTS

Thirty-five CVD events were reported in 30 patients in the analysis set (n = 3813). The incidence of all-cause mortality, MI and stroke was 0.4, 0.6 and 0.1 per 100 patient-years of observation respectively. Among the six men who reported using sildenafil in the month before a nonfatal CVD event, two reported use in the 24 h before the event.

CONCLUSION

The results of the IMHS support previous reports that ED and CVD are often comorbid and share risk factors.

Efficacy of tadalafil once daily in men with diabetes mellitus and erectile dysfunction

AIMS

Erectile dysfunction (ED) is a common comorbidity in men with diabetes mellitus. Tadalafil 10 or 20 mg taken on demand is efficacious and safe for men with diabetes and ED. Recently, continuous treatment with tadalafil has been proposed, addressing ED management as any other chronic condition. This study examined whether once-daily tadalafil 2.5 and 5 mg is efficacious for men with diabetes and ED.

METHODS

This randomized, double-blind, placebo-controlled, multicentre, 12-week study enrolled 298 men with diabetes and ED to once-daily treatment with placebo, tadalafil 2.5 mg or tadalafil 5 mg. Primary efficacy measures were International Index of Erectile Function Erectile Function (IIEF EF) Domain score, and patient success rates for vaginal penetration and completion of intercourse. Patient satisfaction, endothelial function biomarkers, and safety were also assessed.

RESULTS

Patients receiving either dose of tadalafil had clinically and statistically significant improvements in IIEF EF and statistically significant improvements in mean success rates for vaginal penetration, completion of intercourse, and overall treatment satisfaction (P < or = 0.005 tadalafil vs. placebo, all measures). Endothelial dysfunction biomarkers were unchanged. The most common adverse events were headache, back pain and dyspepsia.

CONCLUSIONS

In this first study of men with diabetes and ED, once-daily tadalafil 2.5 and 5 mg was efficacious and well tolerated, suggesting this may be an alternative to on-demand treatment for some men, eliminating the need to plan sex within a limited timeframe.

Sildenafil in the treatment of erectile dysfunction: an overview of the clinical evidence

Erectile dysfunction (ED) is a highly prevalent disease associated with aging as well as with several risk factors including hypertension, heart disease, obesity, dyslipidemia, diabetes, hypogonadism, drugs-related, and pelvic surgery. Many of these factors are components of the metabolic syndrome, a multiplex risk factor for cardiovascular disease (CVD). ED shares common risk factors with CVD. Endothelial dysfunction seems to be the early underlying pathophysiology across both conditions. The efficacy, tolerability and cardiovascular safety of sildenafil has been evaluated in numerous large, randomized, double-blind, placebo-controlled clinical studies in the broad population of men with ED including men with several co-morbid conditions. Sildenafil is effective in several specific patient populations including the difficult-to-treat subpopulations such as diabetes mellitus and after radical prostatectomy. It is associated with rapid onset of action – within 14 minutes for some men – and an extended duration of action for up to 12 hours. Sildenafil improves quality of life and satisfaction for treated men and is well tolerated with a favorable safety profile. New data suggest that sildenafil has beneficial effects in several chronic conditions. It has been approved for the treatment of idiopathic pulmonary hypertension. Numerous articles have suggested that it improves endothelial function and a possible role on premature ejaculation or treatment of lower urinary tract symptoms has been suggested.

Giving patients with erectile dysfunction the opportunity to try all three available phosphodiesterase type 5 inhibitors contributes to better long-term treatment compliance

INTRODUCTION

There are three phosphodiesterase type 5 (PDE5) inhibitors marketed, sildenafil, Vardenafil, and tadalafil for oral treatment of erectile dysfunction (ED). Although the treatment is simple and mostly effective, around 50% has ceased to use the medication within 2 years. One recently described way to improve the compliance is to let the patient try all the three PDE5 inhibitors and to prescribe the drug(s) he and his partner desires.

AIM

To study long-term compliance among patients who were treated according to this "three-drug regime."

MAIN OUTCOME MEASURES

Compliance and reasons for discontinuation after >2 years.

METHODS

The men who, during 2003, were enrolled in a treatment regime, where they had the opportunity to test all the three drugs and to chose the one(s) they preferred, were interviewed in 2006 by telephone concerning their ongoing ED treatment and the reason for discontinuation.

RESULTS

Of the 138 men, mean age 60 years (36-79 years), who had been enrolled and successfully treated with the three-drug regime, 127 (92%) could be reached. The mean follow-up time was 27 months (23-34 months). Of the 127 men, as many as 109 (86%) were still using PDE5 inhibitors. A few (8%) used more than two tablets per week. The majority (44%) used one to two tablets per week or one to two per month (43%), the others (5%) less often. The causes for discontinuation were varying. The most common reason (N = 7) was return of a satisfactory non-assisted erection. Seventy-five percent of the men used only one drug; the others switched between a short- and long-acting drug depending on the situation. It was not uncommon (25%) that the preference had changed during the 3 years of PDE5 inhibitor use.

CONCLUSION

To let patients with ED test the three available PDE5 inhibitors results in an unusually high compliance even under an extended period of time (>2 years).

Interventions for sexual dysfunction following treatments for cancer

BACKGROUND

The proportion of people living with and surviving cancer is growing. This has led to increased awareness of the importance of quality of life including sexual function in people with cancer. Sexual dysfunction (SD) is a potential long-term complication of cancer treatments.

OBJECTIVES

Evaluate effectiveness of interventions for SD following treatments for cancer and their adverse effects.

SEARCH STRATEGY

The Cochrane Pain, Palliative & Supportive Care Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycInfo, AMED, CINAHL, Dissertation Abstracts and NHS Research Register were searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) were included that assessed the effectiveness of a treatment for SD. The trial population comprised of adults of either sex who at trial entry had developed SD as a consequence of cancer treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data and assessed trial quality. Meta-analysis was considered for trials with comparable key characteristics.

MAIN RESULTS

Eleven RCTs with a total of 1743 participants were identified. The quality of the trials was poor. Ten trials explored interventions for SD in men following treatments for non-metastatic prostate cancer. One trial explored effectiveness in women of a lubricating vaginal cream following radiotherapy for cervical cancer. The strongest evidence (from four trials) was on oral phosphodiesterase type 5 (PDE5) inhibitors for erectile dysfunction (ED) following radiotherapy of the prostate or radical prostatectomy. The results using validated measures in all trials significantly favoured those in the PDE5 inhibitor group(s). The combined results of two trials indicated a significantly greater improvement in ED in the PDE5 inhibitor groups (odds ratio (OR) 10.09 95% confidence interval (CI) 6.20 to 16.43). Negative effects were few and usually mild to moderate headaches or flushing. One trial reported more clinically serious events including six events of tachycardia and six of chest pain. Following prostate cancer treatments there was some evidence that PDE5 inhibitors are more effective in combination with acetyl-L-carnitine and propionyl-L-carnitine and that sexual counselling improves self-administration of prostaglandin intra-cavernous injection for SD. There was some evidence following treatment for prostate cancer that transurethral alprostadil and vacuum constriction devices reduce SD, although in both trials negative effects were fairly common. There is some evidence that vaginal lubricating creams reduce SD.

AUTHORS' CONCLUSIONS

PDE5 inhibitors are an effective treatment for SD secondary to treatments for prostate cancer. Other interventions identified need to be tested in further RCTs. The SD interventions in this review are not representative of the range available for men and women. Further evaluations are needed for these interventions for SD following cancer treatments.

Treatment options for erectile dysfunction

A wide variety of medications, devices, and surgical interventions are available to patients who have ED. These range from first-line oral agents to second-line therapy with injections or vacuum devices to third-line options, such as penile prosthesis implantation. In this article, we cover available treatments for erectile dysfunction, ranging from first-line to third-line therapies.

Chronic sildenafil in men with diabetes and erectile dysfunction

Erectile dysfunction frequently represents a neurovascular complication of diabetes mellitus, and it has been calculated that almost 50% of diabetic men will have erectile dysfunction within 6 years after diagnosis. Penile endothelial and smooth muscle cell dysfunction are due to molecular pathway abnormalities (i.e., activation of PKC, increased oxidative stress and overproduction of advanced-glycosylation end products). The response rate to oral drug therapies, such as sildenafil, is lower than in most other groups. Because therapeutic alternatives (i.e., intracavernous injections with vasoactive agents) are not curative, clinical trials aimed to demonstrate rehabilitative effects with daily phosphodiesterase type-5 inhibitors are ongoing. If this approach proves successful, it will determine many advantages over the intracavernosal treatment and potentially induce sexual rehabilitation.

Is sex only for the healthy and wealthy?

OBJECTIVE

To study reasons for Sildenafil (a phosphodiesterase type 5 inhibitor) treatment abortion in erectile dysfunction (ED), with special regard to the relation between cost and use.

METHODS

Men (N = 132) with ED, where treatment with Sildenafil was instituted between 1998 and 2000, were mailed a questionnaire in February 2003, regarding their current ED treatment, including frequency of use, reasons for change or discontinuation, effect on partner relations, and total income of the household.

RESULTS

The response rate was 69%. Nearly every second man (47%) still used Sildenafil at least twice per month. The remaining 53% had aborted oral ED treatment: 10% due to return of normal erections, 43% due to (either alone or in combination): cost of treatment, impaired health, loss of efficacy, change to another ED treatment, or side-effects. Cost was the most common cause (48%) for discontinuation. In low-income households, rationing of treatment or abortion due to the cost was reported significantly (P < 0001) more often (86%) than in high-income households (35%).

CONCLUSION

Just under half of all the patients (47%) used Sildenafil for more than 2 years after initiation of treatment. The cost of the treatment is an important factor for patient compliance in households with a low income, despite the fact that the treatment is highly effective and improves the partner relationship.

Diabetes and the urologist: a growing problem

The incidence of diabetes continues to increase dramatically; this incidence is predominantly of the type-2 form which clusters together with other comorbidities of hypertension and lipid abnormalities, to form the metabolic syndrome. These conditions will have an increasing impact on urological practice, with erectile dysfunction, hypogonadism, voiding difficulties and urinary tract infections all more common in these patients. These symptoms might be the initial presentation of previously undiagnosed diabetes and it is important to recognise this condition early to avoid later complications including end-stage renal failure.

Tadalafil for treatment of erectile dysfunction in men on antidepressants

OBJECTIVE

The objective of this post hoc analysis was to evaluate tadalafil, a treatment indicated for erectile dysfunction (ED), in men on antidepressants.

METHOD

A retrospective, pooled analysis of 19 double-blind, placebo-controlled trials (N = 3864) identified 205 men with ED, mean age of 55 years (range, 27-79 years) receiving antidepressants and tadalafil 10 mg (n = 38), tadalafil 20 mg (n = 113), or placebo (n = 54). Efficacy was measured by the International Index of Erectile Function erectile function domain score, the Sexual Encounter Profile diary, and a Global Assessment Question. Tolerability was assessed via collection and analysis of treatment-emergent adverse events.

RESULTS

Patients on antidepressants who were treated with tadalafil showed significantly greater baseline-to-end point improvement on the International Index of Erectile Function score compared with placebo (end point: tadalafil 10 mg, 21.7; tadalafil 20 mg, 21.8; placebo, 14.5; both P < 0.01). The mean per-patient percent successful intercourse postbaseline was also greater with tadalafil 10 mg (54%) and tadalafil 20 mg (59%) than placebo (29%, both P < 0.05). Patients taking tadalafil 10 (72%) and 20 (76%) mg both reported significant improvement in erections on the Global Assessment Question compared with placebo (33%, both P < 0.01). The incidence of treatment-emergent adverse events was low in all treatment groups with the most common being headache, dyspepsia, and back pain.

CONCLUSION

Tadalafil was well tolerated and improved erectile function in patients taking antidepressant medications.

Does the clinical efficacy of vardenafil correlate with its effect on the endothelial function of cavernosal arteries? A pilot study

OBJECTIVE

To investigate whether the results of the ultrasonographic (US) measurement of post-occlusive changes in the diameters of cavernosal arteries after administering phosphodiesterase type 5 (PDE-5) inhibitor vardenafil could be associated with the response to vardenafil in patients with erectile dysfunction (ED), as currently there are no reliable methods for predicting the success rate of oral PDE-5 inhibitors.

PATIENTS AND METHODS

The study included 122 men with ED; after a complex evaluation, the endothelial function of the cavernosal arteries was assessed in all patients before and 1 h after oral ingestion of vardenafil (20 mg), using our modification of the US assessment of post-occlusive changes in the diameter of cavernosal arteries. After the evaluation, all patients received vardenafil 20 mg on demand for 4 weeks. A successful response was defined using two endpoints, i.e. the normalization of the International Index of Erectile Function Erectile Function domain score (> or = 26) and positive answers to both Sexual Encounter Profile questions 2 and 3 on > or = 75% of occasions, based on the diary data collected.

RESULTS

In all patients the mean (sd) initial percentage increase in the cavernosal artery diameter (PICAD) in responders and nonresponders was not statistically different, at 49 (24) and 43 (26), respectively (P = 0.168), but PICAD values after vardenafil were significantly greater in responders, at 73 (16) vs 55 (23) (P < 0.001). Analysis of data from patients with different causes of ED showed statistically significant differences in PICAD between responders and nonresponders only in those with arteriogenic ED. The sensitivity and specificity of a PICAD of > or = 50% after taking vardenafil 20 mg for predicting a positive response to the same dose of the drug in patients with arteriogenic ED were 94.9% and 91.3%, respectively.

CONCLUSION

The results of the US assessment of post-occlusive changes in the diameter of cavernosal arteries after vardenafil administration are significantly associated with the clinical efficacy of the drug in patients with arteriogenic ED.

Predictors of Tadalafil Efficacy in Men with Erectile Dysfunction: The SURE Study Comparing Two Dosing Regimens

INTRODUCTION

The efficacy of phosphodiesterase-5 inhibitors in the treatment of erectile dysfunction may depend on patient characteristics.

AIM

To determine whether patient characteristics influence the efficacy of two tadalafil dosage regimens and to identify prognostic factors predictive of tadalafil efficacy.

METHODS

This was a multicenter, open-label study in which men with erectile dysfunction were randomized to tadalafil 20 mg either on demand or three times per week for a period of 5-6 weeks. After a 1-week washout period, patients were crossed over to the alternate regimen for another 5-6 weeks.

MAIN OUTCOME MEASURES

Score of the Erectile Function (EF) domain of the International Index of Erectile Function Questionnaire (IIEF) and percentage of positive responses to questions 3 and 5 of the Sexual Encounter Profile (SEP) diary.

RESULTS

A total of 4,262 patients were randomized. A normal EF domain score (> or =26) at the end of on-demand and three-times-per-week treatment was reported by 60.2% and 62.3% of patients, respectively. The percentage of patients who achieved a normal EF domain score and the percentages reporting positive responses to SEP3 and SEP5 depended on the severity of erectile dysfunction and the presence of certain comorbidities, irrespective of the tadalafil dosage regimen. On regression analysis, the two best predictors of tadalafil efficacy were the baseline score of the IIEF-EF domain and the baseline percentage of "Yes" responses to SEP2.

CONCLUSIONS

On-demand and three-times-per-week dosage regimens of tadalafil 20 mg were equally efficacious in men with erectile dysfunction. Among the possible prognostic factors tested in this study, baseline disease severity scores were the strongest predictors of efficacy endpoint scores.

ORIGINAL RESEARCH—ED PHARMACOTHERAPY: Comparing Vardenafil and Sildenafil in the Treatment of Men with Erectile Dysfunction and Risk Factors for Cardiovascular Disease: A Randomized, Double‐Blind, Pooled Crossover Study

INTRODUCTION

Data from head-to-head clinical trials of phosphodiesterase type 5 (PDE5) inhibitors are scarce, making it difficult for clinicians to differentiate among these agents to select the most appropriate treatment for their patients with erectile dysfunction (ED).

AIM

This randomized, double-blind, crossover head-to-head clinical trial compared patient preference, efficacy, and safety of vardenafil and sildenafil in men with ED and diabetes, hypertension, and/or hyperlipidemia.

METHODS

Prospective analysis was performed on two studies in which 1,057 men were randomized to vardenafil 20 mg (N = 530) or sildenafil 100 mg (2 x 50 mg encapsulated tablets) (N = 527) for 4 weeks. Following a 1-week washout, patients switched treatment for 4 weeks.

MAIN OUTCOME MEASURES

Patients were asked about overall preference: "Overall, which medication do you prefer?", plus 11 other preference questions relating to their ED treatment. Efficacy assessments after each treatment period included the erectile function (EF) domain score of the International Index of Erectile Function (IIEF); Sexual Encounter Profile (SEP) diary questions SEP2 and SEP3; Global Assessment Question (GAQ); and Treatment Satisfaction Scale (TSS). Data regarding adverse events were collected throughout the study.

RESULTS

A total of 931 men (mean age 57.9 years) were included in the intent-to-treat (ITT) population. Non-inferiority of vardenafil over sildenafil was achieved for overall preference (vardenafil 38.9%; sildenafil 34.5%; and no preference 26.6%). Additionally, the change from baseline in the EF domain score of the IIEF achieved nominal significance for vardenafil over sildenafil (10.00 vs. 9.40; P = 0.0052). Patients also had a higher percentage of positive responses for vardenafil for SEP2, SEP3, GAQ, and 12 of 19 questions on the TSS. Both drugs were well tolerated.

CONCLUSIONS

This randomized, double-blind, head-to-head trial in ED patients with cardiovascular risk factors demonstrated noninferiority of vardenafil for overall preference. Vardenafil achieved nominal statistical superiority over sildenafil for several frequently used efficacy measures. Both drugs were well tolerated.

Management of sildenafil treatment failures

PURPOSE OF REVIEW

Although oral type 5 phosphodiesterase inhibitors are considered as first-line therapy for the majority of causes of erectile dysfunction, because of their high efficacy, ease of use, and acceptable safety profile, there are some who fail to respond, mainly because of end-organ failure. This communication reviews the management of sildenafil failures in light of recent advances.

RECENT FINDINGS

Sildenafil failures can be attributed to either lack of efficacy or side effects; issues may involve the physician, patient, and his partner. Physicians may contribute to sildenafil failure and discontinuation because of inadequate instructions, lack of adequate follow-up, suboptimal dosing, lack of adequate trial, and insufficient clarification about safety issues. Studies have demonstrated that progression of endothelial dysfunction and diminished cavernosal smooth-muscle content are recognized organic factors which cause end-organ dysfunction and ultimately treatment failure.

SUMMARY

Proper counseling, medication optimization, and modifying associated risk factors can provide success in men who had initially failed sildenafil therapy for erectile dysfunction. Other treatment modalities that may be considered when sildenafil failure occurs include vacuum devices, intraurethral, and intracavernosal administration of vasoactive drugs alone or combined with sildenafil. Penile prosthesis implantation is considered as a last resort, if all first-line and second-line therapies fail.

Self-esteem, confidence, and relationships in men treated with sildenafil citrate for erectile dysfunction: results of two double-blind, placebo-controlled trials

BACKGROUND

Men with erectile dysfunction (ED) often have low self-esteem, confidence, and sexual relationship satisfaction.

OBJECTIVE

We evaluated the impact of sildenafil citrate and its generalizability across cultures on self-esteem, confidence, and sexual relationship satisfaction in men with ED using the Self-Esteem And Relationship (SEAR) questionnaire.

DESIGN

Pooled analysis of 2 double-blind, placebo-controlled, flexible-dose trials of sildenafil with identical protocols: 1 was conducted in the United States and the other in Mexico, Brazil, Australia, and Japan.

PATIENTS

Men > or = 18 years old with ED.

MEASUREMENTS

The impact of treatment on psychosocial factors associated with ED was determined by patient responses to the SEAR questionnaire. Erectile function was determined using the International Index of Erectile Function (IIEF) and a global efficacy question. Successful sexual intercourse attempts were derived from event logs of sexual activity. Treatment effect sizes were calculated for all study outcomes.

RESULTS

Compared with patients who received placebo (n = 274), patients who received sildenafil (n = 279) reported significantly greater improvements (P < .0001) in self-esteem, confidence, sexual relationship satisfaction, and in all sexual function domains of the IIEF. Treatment effect sizes were large (range, 0.7 to 1.2) for all SEAR components, and improvement in psychosocial measures showed moderate to high correlations (range, 0.50 to 0.83, P < .0001) with improvement in erectile function, percentage of successful intercourse attempts, and global efficacy.

CONCLUSIONS

In men with ED from 5 different nations, sildenafil produced substantial improvements in self-esteem, confidence, and sexual relationship satisfaction. Improvements in these psychosocial factors were observed crossculturally and correlated significantly and tangibly with improvements in erectile function.

Prospective, Randomized, Open‐Label, Fixed‐Dose, Crossover Study to Establish Preference of Patients with Erectile Dysfunction after Taking the Three PDE‐5 Inhibitors

INTRODUCTION

We conducted a prospective, randomized, open-label, fixed-dose preference study, with a crossover design, using sildenafil, vardenafil, and tadalafil.

AIM

To assess patient preference for sildenafil (100 mg), vardenafil (20 mg), and tadalafil (20 mg) for the treatment of erectile dysfunction. Secondary objectives included finding out whether patients would follow treatment with a second or third option, in the event that the preferred drug was not available, and to assess side effects.

MAIN OUTCOME MEASURES

Patient preference for any treatment, and evaluation of the elements that patients would assess when choosing one of these drugs.

MATERIAL AND METHODS

Sildenafil (100 mg), vardenafil (20 mg), and tadalafil (20 mg) were taken at least six times over a period of 45-60 days with a washout period of 7 days. A total of 132 patients were enrolled to achieve a valid sample of 90 cases (15 per randomized group, total of six groups). Enrolled patients had mild to moderate erectile function.

RESULTS

The International Index of Erectile Function (IIEF) score improved from baseline and was statistically significant in all cases (P < 0.0001). When we compared the IIEF scores, we found a statistically significant difference between tadalafil and vardenafil (P = 0.0002) favoring the former; similar results were obtained with the Erectile Dysfunction Inventory for Treatment Satisfaction (EDITS) Questionnaire (P = 0.000075). We also found a significant difference (P = 0.012) between tadalafil and sildenafil, again in favor of the former. In assessing drug preference, 25 patients (27.77%) chose sildenafil, 18 (20%) vardenafil, and 47 (52.22%) tadalafil. A total of 94% of patients would be willing to take another drug if the preferred choice was not available. All drugs were well tolerated.

CONCLUSIONS

Although this is a preference study based on subjective elements, statistically significant differences comparing the IIEF score and the EDITS Questionnaire lead us to believe that beyond patients' subjective preference per se, said preference is probably also based on a genuinely superior response to one drug over another.

Research instruments for the diagnosis and treatment of patients with erectile dysfunction

As the incidence and prevalence of erectile dysfunction (ED) increase, healthcare providers will require robust, accurate, and efficient tools for appropriately diagnosing and treating patients with ED. Moreover, clinicians will need effective follow-up tools that assess treatment efficacy and satisfaction, to help patients meet their expectations for successful treatment of ED. We provide a summary of some of the most commonly used instruments for the diagnosis and assessment of ED treatment efficacy that will be referred to in this supplement.

Erection hardness: A unifying factor for defining response in the treatment of erectile dysfunction

The extensive sildenafil citrate erectile dysfunction (ED) database of double-blind, placebo-controlled clinical trials was examined to determine the relation between erection hardness graded on the Erectile Hardness Grading Scale (EHGS) and (1) erectile function (EF), as assessed by the EF domain of the International Index of Erectile Function (IIEF); (2) frequency of erections hard enough for penetration, as assessed by IIEF Q2; and (3) the percentage of successful sexual intercourse attempts according to patient event logs. Pooled data from 6549 men with ED provided strong proof and improved characterization of the response to sildenafil. Almost half of men with ED and a baseline IIEF EF domain score classified as "severe ED" (< or = 10) shifted to a score classified as "no ED" (> or = 26). Sildenafil recipients showed greater mean improvement from baseline to end point in IIEF Q2 scores versus placebo, regardless of baseline ED severity, and a higher mean percentage of successful sexual intercourse attempts occurred during the last 4 weeks of treatment versus placebo (5.4-fold vs 2.0-fold increase from baseline). At end point, 95% of men who scored "no ED" on the IIEF EF domain and 92% of men who reported "almost always/always" achieving an erection hard enough for penetration (IIEF Q2) had graded their erections hard (rigid) enough for penetration (grade 3) or completely hard and fully rigid (grade 4) during the last 4 weeks of treatment, suggesting that the IIEF EF domain and IIEF Q2 may be good surrogate end points for erection hardness. Furthermore, during the last 4 weeks of treatment, the percentage of grade 3 and/or 4 erections correlated positively with the percentage of successful sexual intercourse attempts. Hence, hard erections may be considered a unifying factor that defines response to ED treatment. Completely hard and fully rigid erections (grade 4) should be recognized as the optimal goal of an ED therapy. Evidence presented here demonstrates that sildenafil significantly improved EF as assessed by the IIEF EF domain and assessments of erection hardness in patients with ED; a dose-response relation was observed in the proportions of men with ED who graded their erections hard (rigid) enough for sexual penetration or completely hard and fully rigid.

Efficacy and safety of tadalafil across ethnic groups and various risk factors in men with erectile dysfunction: Use of a novel noninferiority study design

AIM

This U.S. multicenter open-label study used a noninferiority trial design to assess the efficacy of tadalafil 20 mg to treat erectile dysfunction (ED) in the black American and Hispanic groups compared with a reference group of Caucasians. A secondary objective was to demonstrate the efficacy and safety of tadalafil 20 mg in various populations of men with ED.

METHODS

A total of 1,911 patients with ED were enrolled into eight predefined groups: (1-3) Caucasian (Reference group), Black American, or Hispanic patients, < or =65 years of age with no diabetes mellitus or depression; (4) patients with depression, < or =65 years of age, no diabetes; (5) patients with diabetes, < or =65 years of age, no depression; (6) patients >65 years of age, no diabetes or depression; (7) patients who met enrollment criteria but were not included in any other group; and (8) patients with ED due to traumatic spinal cord injury. The study had a 4-week run-in period, followed by a 12-week treatment period with tadalafil taken as needed, up to one dose/day, prior to sexual activity. Change from baseline to endpoint in the Erectile Function (EF) domain of the International Index of Erectile Function (IIEF) was used to determine noninferiority of groups 2 and 3 from group 1. Secondary efficacy measures included other IIEF domains and Sexual Encounter Profile (SEP).

RESULTS

Noninferiority analyses based on the EF domain score showed that tadalafil was as efficacious in the Hispanic and Black American groups as in the Reference group. Patients in each of the eight groups had a significant change from baseline (P < 0.001) in the IIEF EF domain score and positive responses to SEP Questions 1-5. The most common treatment-emergent adverse events reported by patients in all eight groups were headache, nasal congestion, dyspepsia, flushing, and back pain.

CONCLUSION

Tadalafil 20 mg was as efficacious in the Hispanic and black American groups as in the Caucasian/Reference group. Tadalafil was efficacious and well tolerated in each of the groups studied in this trial.

Pharmacology of erectile dysfunction in man

Erectile dysfunction (ED) is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity (2nd International Consultation on Sexual Dysfunction-Paris, June 28th-July 1st, 2003). Following the discovery and introduction of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost and many preclinical and clinical papers have been published in the last 5 years. This review is structured in order to give the reader an overview of the clinical and preclinical data available on the peripheral regulation of and the mediators involved in human penile erection. The most widely accepted risk factors for ED are discussed. The article is focused on human data, and the safety and effectiveness of the 3 commercially available Phosphodiesterase-5 (PDE5) inhibitors used to treat ED are also discussed.

Effectiveness of sildenafil in treating erectile dysfunction in PTSD patients: a double-blind, placebo-controlled crossover study

OBJECTIVE

Post Traumatic Stress Disorder (PTSD) is known to be associated with Erectile Dysfunction (ED). Sildenafil citrate was shown to be effective treatment for ED among different clinical populations. However, to date, no placebo-controlled trial has assessed sildenafil's effectiveness for treating ED in PTSD patients. The goal of the present study was to address this question using a double-blind placebo controlled crossover design.

METHODS

A four-week double-blind crossover trial of sildenafil (50 mg up to 100 mg per usage) versus placebo was conducted on 21 outpatients diagnosed with chronic PTSD accompanied by ED. Erectile function was assessed biweekly using the International Inventory of Erectile Function (IIEF). Depressive symptoms, PTSD symptoms and subjective well-being scores were assessed as well.

RESULTS

Analysis of IIEF scores revealed a main effect of treatment phase (E = 33.361, df =2, P < 0.000). Pairwise comparisons showed that sildenafil IIEF scores (mean = 45.19 +/- 15.05) were significantly higher compared to baseline scores (mean = 20.00 +/- 12.32, P = 0.000) and placebo scores (mean = 33.04 +/- 12.99). Compared to placebo, a significant improvement was also observed during the sildenafil phase in erectile function, orgasmic function and sexual desire. There was no significant change in depression, PTSD symptoms or subjective well-being.

CONCLUSION

The results of this study suggest that sildenafil citrate treatment for ED in PTSD patients was accompanied with improvement of ED symptoms and was found to be significantly better than placebo. Nevertheless, this effect should be considered marginal since patients still meet the criteria of ED after treatment. Larger, parallel group studies are warranted.

Sildenafil citrate (Viagra) treatment for erectile dysfunction: An updated profile of response and effectiveness

In the 7 years since sildenafil citrate (VIAGRA) was introduced as the first oral phosphodiesterase type 5 inhibitor therapy for erectile dysfunction, it has been used to treat nearly 27 million men with erectile dysfunction worldwide. Patient populations with erectile dysfunction of varying etiologies and with diverse comorbidities have benefited from sildenafil treatment. This update focuses on relatively recent research that further defines the response and effectiveness profiles of sildenafil and provides additional insight into optimizing treatment. In addition to providing recent data on sildenafil efficacy and safety/tolerability, the update provides data on assessments of erection hardness, measures of psychosocial outcomes (e.g., emotional well-being and treatment satisfaction), and treatment approaches to maximize response and effectiveness (e.g., by titrating to the maximum tolerated dose). Increased understanding of the sildenafil response and effectiveness profiles and optimal sildenafil treatment are central to the appropriate management of erectile dysfunction using sildenafil.

A meta-regression analysis of treatment effect modifiers in trials with flexible-dose oral sildenafil for erectile dysfunction in broad-spectrum populations

Several trials and reviews provide evidence for the efficacy of phosphodiesterase-5 inhibitors in the treatment of erectile dysfunction (ED). However, little is known about the impact of treatment effect modifiers other than concomitant diseases. Our objective was to identify patient and trial characteristics as well as methodological and publication-related issues that are associated with the treatment effect measured in flexible-dose randomized controlled trials of oral sildenafil for ED. The MEDLINE and the Cochrane Central databases were searched for efficacy trials of sildenafil. Thirteen trials fulfilled all inclusion criteria. A series of meta-regression and graphical analyses were performed to test the impact of possible effect modifiers. Treatment effect was influenced by mean baseline disease severity and mean duration of the disease. These associations were at least partly mediated by placebo response. Trial duration, age of patients and etiology of ED in patients did not have any significant influence on the treatment effect. The year of publication of primary trials was also related to trial findings. Our analysis adds important data to enable the control of confounding variables in future trials and meta-analyses. It might also help the individual to assess the unbiased efficacy and true innovative potential of available and forthcoming pharmacological agents.

Tolerance to the Therapeutic Effect of Tadalafil Does Not Occur During 6 Months of Treatment: A Randomized, Double‐Blind, Placebo‐Controlled Study in Men with Erectile Dysfunction

INTRODUCTION

Tolerance can cause a decrease in drug efficacy during chronic therapy, possibly leading to treatment failures.

AIM

The aim of this article is to determine whether tolerance developed to the effects of tadalafil on erectile function (EF) over a 6-month treatment period.

METHODS AND MAIN OUTCOME MEASURES

Post hoc analysis of data from a multicenter, double-blind, randomized, placebo-controlled, parallel group study was performed. Men (> or =18 years of age) with erectile dysfunction (ED) were randomized to treatment with placebo (N = 47) or 20-mg tadalafil (N = 93) taken as needed for 6 months. This report focuses on efficacy assessed with the Sexual Encounter Profile (SEP) diary (diaries were collected after a 4-week treatment-free run-in period [baseline], and monthly for 6 months), and with the International Index of Erectile Function (IIEF) (administered at baseline, and at 3 and 6 months). RESULTS. The mean per-patient percentage "yes" response on SEP question 3 (SEP3, successful intercourse) was 33 +/- 4% at baseline, 74 +/- 4% after 1 month, and 78 +/- 4% after 6 months of tadalafil treatment. The IIEF EF domain score was 16.2 +/- 0.7 at baseline, 24.3 +/- 0.8 after 3 months, and 24.3 +/- 0.9 after 6 months of tadalafil treatment. In a subgroup of patients who took tadalafil > or =3 times per week (N = 24), the SEP3 score was 87 +/- 4% after 1 month and 93 +/- 3% after 6 months of treatment, and the IIEF EF domain score was 27.3 +/- 0.9 after 3 months and 28.5 +/- 0.4 after 6 months. Of 16 tadalafil-treated patients who discontinued, three cited a lack of efficacy.

CONCLUSIONS

Tadalafil treatment significantly improved SEP3 and IIEF EF domain scores. The efficacy of tadalafil, taken as needed, was maintained over a 6-month treatment period in men with ED.

Drug Insight: oral phosphodiesterase type 5 inhibitors for erectile dysfunction

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men. At present, first-line oral pharmacotherapy for most patients with ED is a phosphodiesterase type 5 (PDE-5) inhibitor, of which three are currently available worldwide. Sildenafil (Viagra, Pfizer) has a very satisfactory efficacy-safety profile in all patient categories. The first PDE-5 inhibitor to reach the market, it is now the most widely prescribed oral agent for ED. Tadalafil (Cialis, Lilly ICOS) and vardenafil (Levitra, Bayer/GlaxoSmithKline) were introduced to the European Union and the US in 2003 and 2004, respectively. These three PDE-5 inhibitors share many characteristics, but each has unique features. This review describes the chemical, pharmacologic and clinical features of sildenafil, vardenafil and tadalafil as oral first-line treatments for ED. First, we describe the physiology of penile erection and PDE-5 inhibitor pharmacology, including chemistry, PDE selectivity, pharmacokinetics, and possible drug interactions. We then summarize data on the efficacy and safety profiles of the three PDE-5 inhibitors for the treatment of ED in the general population, in patients with diabetes mellitus and in men that have undergone bilateral nerve-sparing retropubic radical prostatectomy.

Sensitivity of the psychological and interpersonal relationship scales to oral therapies for erectile dysfunction

INTRODUCTION

Studies of erectile dysfunction (ED) therapies typically assess erectile function end- points, although other treatment outcomes may also be of value to men and their partners. Aim. To examine the treatment sensitivity of the Psychological and Interpersonal Relationship Scales (PAIRS) associated with the use of two phosphodiesterase type 5 (PDE5) inhibitors with different duration of action.

METHODS

Men with ED were recruited from three clinical trials of tadalafil and sildenafil citrate to complete post-treatment questionnaires that included the PAIRS. In study 1, the PAIRS was assessed after 6 months of open-label tadalafil (20 mg) treatment and after 2 months of real-world sildenafil use (25-100 mg). In studies 2 and 3, the PAIRS was assessed at the end of the trial assessment phase. In study 2, men with a 6-24 week history of sildenafil use (25-100 mg) received 3 weeks of open-label sildenafil treatment (dosage at study entry), and then switched to 9 weeks of tadalafil treatment. In study 3, a double-blind, crossover study, men were randomized to 12 weeks of either tadalafil (20 mg) or sildenafil (50 mg) treatment, followed by 12 weeks of the alternate treatment; PAIRS scores for the second treatment period were evaluated.

MAIN OUTCOME MEASURE

Treatment outcomes were assessed with the PAIRS, a new reliable and valid self-report measure of sexual self-confidence, spontaneity, and time concerns before sex.

RESULTS

Significant mean differences were observed on all PAIRS domain scores associated with tadalafil and sildenafil treatment. Across studies, men had significantly higher sexual self-confidence and spontaneity scores, and lower time concerns scores in reference to tadalafil compared with their scores in reference to sildenafil.

CONCLUSIONS

Mean differences observed on PAIRS domains across studies support the sensitivity of the measure to differentiate between these two ED treatments.

Prescribing all phosphodiesterase 5 inhibitors to a patient with erectile dysfunction--a realistic and feasible option in everyday clinical practice--outcomes of a simple treatment regime

OBJECTIVE

In clinical practice, to apply and evaluate outcomes of a treatment regime, in which the patient had the opportunity to try all the available phosphodiesterase 5 (PDE5) inhibitors.

METHODS

Patients eligible for treatment with PDE5 inhibitors were prescribed 8 tablets with a shorter-acting substance (four tablets sildenafil 100mg and four tablets vardenafil 20mg) and eight tablets with a long-acting substance (tadalafil 20mg). Outcomes of the regime were recorded.

RESULTS

Of the 186 patients, 64 (34%) had not been treated previously (naïve), and 122 (66%) were undergoing treatment for their erectile dysfunction. The overall treatment response was 89% (165 of 186 patients); 78% (n=145 of 186 patients) tested all three substances. No significant difference in choice between long- and shorter-acting medications in the overall material was observed. Two thirds of the naïve patients (n=64) preferred a shorter-acting substance (p<0.01). Every fifth man requested both a shorter- and a long-acting medication to accommodate his need.

CONCLUSION

If patients are given the opportunity in clinical practice to try all three available PDE5 inhibitors, the overall response rate is very high, almost 90%. No significant difference in patient preference between long- and shorter-acting drugs was observed. Treatment choice was based mainly on efficacy or duration of effect.

Comparison Between Sildenafil‐Treated Subjects with Erectile Dysfunction and Control Subjects on the Self‐Esteem And Relationship Questionnaire

INTRODUCTION

Erectile dysfunction (ED) can negatively impact psychosocial measures of a patient's sexual life.

AIM

To evaluate self-esteem, confidence, and relationships in men with ED, before and after treatment with sildenafil citrate (Viagra), with reference to controls without ED.

METHODS

Sildenafil-naïve patients with ED were enrolled in a 10-week, open-label, flexible-dose (25 mg, 50 mg, or 100 mg) trial of sildenafil. In a separate study, men without ED who did not take sildenafil also completed the Self-Esteem And Relationship (SEAR) questionnaire. In addition to traditional statistical testing, equivalency testing was applied to compare the ED group, before and after treatment, with the control group and to examine whether the ED group improved to normative ranges on the SEAR questionnaire after treatment (within half a standard deviation of the normative or control group mean).

MAIN OUTCOME MEASURES

Baseline and end-of-treatment responses on psychosocial aspects of ED were measured with the validated SEAR.

RESULTS

Mean SEAR scores between subjects with ED (N = 93, mean age 55.0 years) at baseline and control subjects without ED (N = 94, mean age 52.5 years) were statistically different from zero and not statistically equivalent. Conversely, mean SEAR scores between ED subjects after treatment and control subjects were statistically equivalent and not statistically different from zero.

CONCLUSIONS

The results indicate that sildenafil is associated with normalization of relationships, confidence, and self-esteem in men with ED.

Endothelial and erectile dysfunction, diabetes mellitus, and the metabolic syndrome: common pathways and treatments?

The past decade has witnessed a dramatic increase in the prevalence of obesity. Comorbidities of obesity include type 2 diabetes mellitus, hypertension, and lipid abnormalities, all of which contribute to cardiovascular disease (CVD) and are associated with endothelial dysfunction. These abnormalities frequently cluster in individuals, and the term metabolic syndrome is now widely used to define this cluster. The syndrome is frequently (although not invariably) associated with insulin resistance and CVD. Diabetes is associated with CVD, which may be asymptomatic in some cases, particularly when associated with autonomic neuropathy. This has implications for guidelines on the evaluation of patients with erectile dysfunction (ED) and CVD. Treatment of ED in men with diabetes has been revolutionized by the introduction of phosphodiesterase 5 inhibitors. However, men with diabetes tend to respond less positively to these agents, at least as currently prescribed. This decreased responsiveness may be related to the severity of endothelial function in patients with diabetes. Additional therapeutic strategies may be needed to overcome this problem.

Erectile dysfunction and treatment of carcinoma of the prostate

Prostate cancer is the leading malignancy in men in the United States and causes more than 60,000 deaths annually. Treatment of prostate cancer, whether it be with surgery, radiation therapy, cryotherapy, or medical treatment, is associated with significant life-altering morbidity. Incontinence and erectile dysfunction (ED) too often are sequelae of these treatment alternatives. ED can be a significant complication and can alter the life of the patient with prostate cancer and his partner. Newer modifications of the radical prostatectomy with nerve-sparing techniques are the cornerstone of erection preservation. Time following radical prostatectomy has been shown to increase erectile function such that more patients have functional erections at 3 years than 1 year after surgery. With the advent of phosphodiesterase-5 (PDE-5) inhibitors, many men can have improved functional erections and return to active coitus. Prevention of ED also is an important management technique. Evidence is gathering that prophylaxis with regular vasoactive injection or daily PDE-5 agents may be an integral part of preservation of corpus cavernosum smooth muscle function. Combination medical therapy and surgical penile prosthesis implantation also are options for patients who do not respond to oral PDE-5 inhibitors.

Evaluation of a progressive treatment program for erectile dysfunction in patients with diabetes mellitus

The aim was to evaluate the effectiveness of a progressive program, starting with simple methods and, when not effective, moving to more complex methods, to treat erectile dysfunction (ED) in patients with diabetes mellitus. A total of 284 diabetic patients with ED entered into a 6-phase program starting with sildenafil citrate (Viagra). Those with contraindications, side effects, or negative response (erection insufficient for vaginal penetration) were switched to the vacuum erection device (VED), and then progressively (for failures) to intracavernous injection (ICI), sildenafil citrate+ICI, ICI+VED, and penile prosthesis. Patients were followed for 2 y. Of the 284 patients 276 patients were eligible for sildenafil citrate and 147 (53.3%) responded positively, but 25 (9.1%) patients stopped it soon due to adverse effects. Of 162 patients (129 nonresponders, eight noneligible for the sildenafil and 25 patients who dropped out due to adverse effects), treated with VED, 114 (70.4%) responded well, however, only 19 (11.7%) patients agreed to continue its use. Of the remaining 143 patients (nonresponders, noneligible for the previously mentioned treatments and patients who dropped out due to adverse effects), 103/143 (72%) responded to ICI, 27/40 (67.5%) to sildenafil+ICI, and 9/13 (69.2%) to ICI+VED. Four patients received a penile implant. At the 2 y follow-up, 81 of 284 patients who entered the study (28.5%) were still responding to sildenafil, seven (2.5%) to VED, 113 (39.8%) to ICI, 24 (8.5%) to sildenafil+ICI, two (0.7%) to ICI+VED; 15 (5.3%) had a penile implant. In all 17 (6%) patients reported spontaneous erections, 11 (3.9%) stopped the treatment due to family reasons and 14 (4.9%) failed the treatment. In conclusion, the progressive treatment program for ED seems to be very effective for diabetic patients, yielded a complete response for short-term and 91.2% rate of success at the end of 2 y follow-up.

The efficacy and safety of PDE5 inhibitors

Inhibition of phosphodiesterase-5 (PDE5) reduces the degradation of cyclic guanosine monophosphate, which allows erectile function to occur by relaxation of penile smooth muscle. Three PDE5 inhibitors (sildenafil, tadalafil, and vardenafil) in a range of doses are available. PDE5 therapy, compared with placebo, significantly improves scores on the International Index of Erectile Function and has been found to be effective in special clinical populations, such as those with prostate cancer, diabetes, and cardiovascular disease. Sildenafil and vardenafil show some interaction with food intake. Time to onset of action is usually 30-120 minutes, but there are reports of shorter times to onset of action. The duration of action of sildenafil and vardenafil is about 4 hours, whereas that of tadalafil is about 36 hours. The overall safety of the treatments is good, even in patients with a history of cardiovascular disease. However, there is a risk of hypotension if nitrates are given concurrently. Increased QTc intervals have been reported, the longest with vardenafil, shortest with tadalafil, and intermediate with sildenafil. Priapism and prolonged erection are rare adverse events. Common side-effects include headache, facial flushing, nasal congestion, and dyspepsia. There may be interactions with other medications metabolized in a similar way, such as erythromycin and HIV protease inhibitors.

Clinical update on phosphodiesterase type-5 inhibitors for erectile dysfunction

Erectile dysfunction (ED) affects the sexual lives of millions of men. The first-line oral pharmacotherapy for most ED patients is phosphodiesterase type-5 (PDE-5) inhibitors, of which three are available. Sildenafil is the most widely prescribed oral agent for ED and has a very satisfactory efficacy-safety profile in all patient categories. Tadalafil and vardenafil were introduced in the European Union and in the United States in 2003 and 2004, respectively. The three PDE-5 inhibitors share many pharmacological and clinical characteristics, and each has unique features. This review, which is based on the contemporary literature on PDE-5 inhibitors, describes the chemical, pharmacological, and clinical features of sildenafil, vardenafil, and tadalafil. The first section reviews the pathophysiology of penile erection and PDE-5 inhibitor pharmacology. The second section summarizes data regarding efficacy and safety of the three drugs in treating ED in the general population as well as in selected patient categories.

Psychosocial Evaluation and Combination Treatment of Men with Erectile Dysfunction

The Sexual Tipping Point forms the foundation of a biopsychosocial model to help conceptualize a combination treatment, where sex coaching and sexual pharmaceuticals are integrated into a clinical approach, which addresses organic, psychologic, and cultural issues for men with erectile dysfunction (ED). At any moment in the intervention pro-cess, the clinician determines the most elegant solution, which focuses the majority of effort on fixing the predominant factor while not ignoring the others. Clinicians using this model, can fully conceptualize ED by understanding the predisposing, precipitating,and maintaining psychosocial aspects of their patient's diagnosis and management, as well as organic causes and risk factors. The sex status or focused sex history, and continuous reassessment based on follow-up are the core elements of this method. Restoration of lasting and satisfying sexual function requires a multidimensional understanding of all of the forces that created the dysfunction, whether a solo clinician or multidisciplinary team approach is used. Each clinician needs to carefully evaluate their own competence and interests when considering the treatment of a man's ED, so that regardless of the modality used, the patient receives optimized care to restore sexual function and satisfaction.

Outcome analysis of sildenafil citrate for erectile dysfunction of Japanese patients

The approved maximal dose of sildenafil is only 50 mg in Japan, but the impact of dose regulation on treatment outcomes has not been established. Moreover, the contributors to the efficacy in patients having an intact peripheral nervous system have not been fully elucidated. We assessed in Japanese patients the treatment outcomes of sildenafil for erectile dysfunction (ED) under regulation of the approved dose and identified factors contributing to its efficacy among those with various etiologies other than pelvic surgery. We retrospectively reviewed 196 ED patients treated with sildenafil. The overall efficacy was 70.9% (139/196), and patients with psychological problems and concomitant cardiovascular disease showed high response rates (82.4 and 87.0%, respectively). Of the 139 responders, 89.9% achieved efficacy with a dose of 25 or 50 mg. Logistic regression analysis revealed concomitant cardiovascular disease and a favorable nocturnal penile tumescence result to be independent contributors to the efficacy.

Sildenafil: efficacy, safety, tolerability and mechanism of action in treating erectile dysfunction

Sildenafil citrate is marketed under the trademark name Viagra and is widely used to treat male erectile dysfunction; therapeutic uses of this medication for other diseases related to vascular dysfunction are emerging. When used as recommended, the drug has a strong clinical efficacy and safety profile in a broad spectrum of the male population. Its widespread use and effects of long-term exposure to the drug due to particular treatment regimens or inappropriate use mandate an ongoing update of its molecular mechanism, pharmacological profile and associated safety issues. This review focuses on biochemical and pharmacological features of sildenafil, the active component in Viagra, interaction of sildenafil with phosphodiesterase 5, pharmacokinetic parameters, action in smooth muscle, side effects, safety profile and prospects for other uses.

The Efficacy of Tadalafil in Clinical Populations

OBJECTIVES

To evaluate the efficacy of tadalafil in men with erectile dysfunction (ED) by demographic and ED characteristics, in patients having various comorbid medical conditions, and in patients receiving drug treatment for other medical conditions.

METHODS

This is an analysis of 11 double-blind, placebo-controlled trials with 2,102 men with a broad spectrum of ED etiology and various comorbid medical conditions as participants. The variables analyzed in this report included race, age, body mass index (BMI), ED etiology, ED severity, ED duration, smoking, prior sildenafil use, presence of comorbid conditions (diabetes mellitus, hypertension, cardiovascular disease, hyperlipidemia, depression, benign prostatic hyperplasia), and treatment with antihypertensives or antidepressants. Patients were randomly assigned to receive tadalafil 10 mg (N=321), tadalafil 20 mg (N=1,143), or placebo (N=638). The primary efficacy variables included mean changes from baseline in the erectile function (EF) domain score of the International Index of Erectile Function (IIEF) questionnaire, and the mean per-patient percentage of "yes" responses to the Sexual Encounter Profile (SEP) diary question 3 (SEP3--successful intercourse). The Global Assessment Question 1 (GAQ) was evaluated, as was the percentage of men attaining a normal IIEF EF domain score at end point.

RESULTS

Patients taking tadalafil 10 mg or 20 mg demonstrated significant improvement (P<0.005) from baseline to end point on the IIEF EF domain score in all subpopulations analyzed compared with patients receiving placebo. The mean-per-patient percentage of "yes" responses to SEP3 increased significantly in all subpopulations taking tadalafil compared with placebo (P<0.05). Tadalafil-treated patients had a significantly greater positive response rate on the GAQ in all subpopulations analyzed compared with placebo-treated patients (P<0.03) except for the tadalafil 10 mg cardiovascular subpopulation (placebo, 46.8%; tadalafil 10 mg, 71.0%; P=0.127). The percentage of positive responses ranged from 72% to 91% for patients on tadalafil 20 mg and from 52% to 94% for tadalafil 10 mg compared with a range of 20% to 47% for placebo-treated patients.

CONCLUSIONS

Tadalafil was effective in improving erectile function across a wide spectrum of ED patients including patients with various comorbid conditions.

Sildenafil Non-Responders: Haemodynamic and Morphometric Studies

OBJECTIVES

Most of the available data on efficacy for sildenafil are based on a questionnaire and erectile dysfunction (ED) is classified with minor or severe organic factors. To better select sildenafil responders and non-responders, we have conducted a haemodynamic and morphometric study in sildenafil non-responders.

METHODS

Thirty patients with ED aged from 28 to 74 years-old did not respond to 8 attempts of 100 mg of sildenafil. They underwent hormonal measurements, intracavernous injection (ICI 20 microg PgE1) followed by Doppler examination and cavernosometry. A penile biopsy was performed under local anesthesia. A quantification of the cavernous smooth muscle (SMC) was performed with a computerized image analysis after staining with actin anti-actin.

RESULTS

Twenty-eight patients had a very poor ICI response. Five patients were diabetic and 2 had low testosterone level. Eight patients had arterial lesions, 15 had venous leak and 5 both lesions. They all had reduction of SMC (<35%). No biological and vascular abnormality was observed in two patients. They had a percentage of SMC of 38% and 42%. No complication was observed with the penile biopsy.

CONCLUSIONS

Severe vascular lesions and atrophy of SMC are mainly observed in sildenafil non-responders. The age, diabetes and low testosterone level seem not to be related with the failures.

Past, present, and future: a 7-year update of Viagra (sildenafil citrate)

More than 30 million men are estimated to have erectile dysfunction (ED) in the United States. Worldwide, ED is estimated to affect more than 150 million men, and that number is expected to exceed 300 million men by the year 2025. The prevalence of ED ranges from 7% in men aged 18-29 years to 85% in men aged 76-85 years. In addition, a recent report showed that 68% of patients with ED aged 18 years and older have at least one comorbid diagnosis of hypertension, hyperlipidaemia, diabetes or depression, and research suggests that ED may be an early indicator of systemic vascular disease. Viagra (sildenafil citrate), the first-in-class phosphodiesterase type 5 (PDE5) inhibitor, was introduced in 1998 for the treatment of ED. In the 7 years since its market launch, more than 750,000 physicians have prescribed sildenafil to more than 23 million men, helping establish an excellent safety and efficacy record. Clinical studies have demonstrated that sildenafil successfully treats ED of varied organic, psychogenic or mixed aetiology, and is effective in men with ED and comorbidities such as hypertension, hyperlipidaemia, diabetes or depression. Sildenafil was a breakthrough medication that addressed a previously unfulfilled medical need. The impact of sildenafil has stimulated academic, clinical and industrial research to better understand the nature of sexual function and develop better treatment and management for sexual dysfunctions such as ED. With the advent of other erectogenic therapies for the treatment of ED, this 7-year update will focus on the unique history and development of sildenafil, its current use and applications and its future directions and indications. Special emphasis is placed on the impact of sildenafil on our understanding of sexual health and on the extensive safety and efficacy data that have been amassed from numerous clinical trials.

Erectile dysfunction: anatomical parameters, etiology, diagnosis, and therapy

Functional anatomy of the human penis involves various parameters: cavernous tissue, covering integument, prepuce foreskin, corpora cavernosa, corpus spongiosum, glans, facia, arterial supply, venous drainage, lymph drainage, musculature, and nerve supply. Several factors affect the expression/degree of erectile dysfunction (ED) endocrine profile, aging/senescence, demyelinating diseases, and surgery. Risk factors of ED are: age, vascular factors, metabolic diseases (diabetes mellitus), neurologic diseases, and HIV/AIDS. Several drugs are associated with ED: antiandrogenic, anticholinergic, antidepressants, antihypertensive, major tranquilizers, anxiolytics, and certain medicines/metabolites. The International Index of Erectile Function (IIEF) is a multidimensional scale for assessment of erectile dysfunction. The main structures mediating erection are the corpora cavernosa or "erectile bodies," which are fused distally for approximately three-quarters of their length. They separate proximally to fuse with each ischial tuberosity of the pelvis. On their ventral surface lies the corpus spongiosum, which surrounds the urethra. Coital dysfunction is classified into "erectile dysfunction" (psychosexual and endocrine/neuro-endocrine) and "ejaculatory dysfunction" (psychosexual, and genitourinary surgery). Vasculogenic impotence was evaluated by high-resolution ultrasonography and pulsed Doppler spectrum analysis. Cavernosal, alpha-blockade is a technique used to evaluate and treat ED. Another diagnostic procedure for ED involves color floro and spectural Doppler imaging after papaverine-induced erection in impotent men. Color Doppler and duplex ultrasonography are used to evaluate Peyronie's disease. Sildenafil cilrate (Viagra) is an effective therapy of ED in men. Vardenavil is a highly selective phosphodiesterase 5 (PDE5) inhibitor which improved ED. Prostagland E1, vasoactive intestinal polypeptide (VIP), and phentolamine mesylate (administered by autoinjectors) have been applied to treat ED in patients resistant to other intracavernosal agents. Clinical trials were conducted on self-injection of vasoactive drugs, apomorphine SL, and tadalafil in diabetic men. Medical therapy of ED includes: medicated urethral system for erection (MUSE), intravenous pharmacotherapy, arterial revascularization, vacuum devices, two- and three-component inflatable penile prosthesis, semi-rigid penile prosthesis in situ, and inflatable one-piece penile prosthesis. Surgical therapy include procedures to correct Peyronie's penile deformity and penile deformity, procedures to avoid inevitable shortening accompanying Nesbit's disease, and for penile lengthening.