Tadalafil relieves lower urinary tract symptoms secondary to benign prostatic hyperplasia

Erectile dysfunction and cardiovascular disease: efficacy and safety of phosphodiesterase type 5 inhibitors in men with both conditions

Risk factors for cardiovascular disease and erectile dysfunction (ED) are similar, as might be expected given their shared etiologic and pathophysiologic origins. It is now generally accepted that most cases of ED result from a vascular disturbance of the endothelium. Recent epidemiological studies have documented a strong association between ED and comorbid conditions such as hypertension, diabetes mellitus, and dyslipidemia. Phosphodiesterase type 5 (PDE5) inhibitors are recommended as first-line therapy for erection problems of all etiologies and severities. The efficacy and safety of PDE5 inhibitors in the general ED population is well documented and has been extensively reviewed. To examine the association between ED and vascular disorders in the context of current knowledge regarding PDE5 inhibitors, an electronic search was performed of articles published from January 2002 through April 2008 using the PubMed, EMBASE, and MEDLINE databases. Although preference was given to randomized, blinded, controlled clinical trials, data from retrospective studies were also reviewed when appropriate. This analysis revealed that the clinical evidence linking ED to future cardiovascular events is compelling, presenting physicians with a unique interventional opportunity to address underlying cardiovascular health concerns in men presenting with ED. In most studies, PDE5 inhibitors were shown to effectively and safely improve erectile function regardless of cause, severity, or presence of comorbid conditions, including hypertension, diabetes mellitus, and dyslipidemia.

Erectile dysfunction and lower urinary tract

During the last decades it turned out that the NO/cGMP signaling cascade is one of the most prominent regulators of a variety of physiological and pathophysiological processes in a broad range of mammalian tissues. Thus cGMP is a key second messenger and targeting this pathway by increasing intracellular cGMP levels is a very successful approach in pharmacology as shown for nitrates, PDE5 inhibitors and more recently for stimulators of the guanylate cyclase. Besides the beneficial effects of cGMP elevation in cardiac, vascular, pulmonary, renal or liver disorders the launch of PDE5 inhibitors for the treatment of erectile dysfunction 10 years ago, has directed a lot of attention to the NO/cGMP signaling in the lower urinary tract. Triggered by the use of PDE5 inhibitors in ED it turned out that cGMP is a common regulatory mechanism for lower urinary tract function also beyond ED. In recent years intense research and development efforts were undertaken to elucidate the role of the NO/cGMP and to fully exploit the therapeutic implications of cGMP elevation in urological disorders in ED and beyond. Therefore we have summarized the effects of cGMP elevation for treatment of erectile dysfunction in males and in females. We have also reviewed the recent pre-clinical and clinical lines of evidence for treatment options of benign prostatic hyperplasia and lower urinary tract symptoms in male patients and overactive bladder and urinary incontinence in female patients. In addition we also touch more speculative concepts using cGMP elevating drugs for the treatment of premature ejaculation, peyornies disease and stone disease.

Increased sexual dysfunction in men with storage and voiding lower urinary tract symptoms

INTRODUCTION

Sexual dysfunction (SD) and lower urinary tract symptoms (LUTS) are highly prevalent in men and increase with age. Previous studies have shown that LUTS and SD are highly associated in men, but most have not distinguished between voiding and storage LUTS. Aims. Assess impact of voiding and storage LUTS on recorded diagnosis of SD in men in U.K. general practice.

METHODS

Identified records of patients with SD and storage (e.g., overactive bladder) and voiding LUTS (e.g., benign prostatic hyperplasia) from a population-based study using The Health Improvement Network database with records from 333 general practices. Study period was 2000-2007; study population was men aged >or= 18 years.

MAIN OUTCOME MEASURES

Prevalence rates of SD, and storage and voiding LUTS on January 1 of each year from 2000 to 2007.

RESULTS

Overall prevalence of recorded SD rose from 1.7% in 2000 to 4.9% in 2007. The prevalence of storage and voiding LUTS also increased. Median age at diagnosis was 60 years for erectile dysfunction (ED), 62 years for other SD, 62 years for storage LUTS, and 61 years for voiding LUTS. Compared to men with no LUTS, odds ratios (95% CI) for ED were as follows: storage LUTS, 3.0 (2.6-3.4); voiding LUTS, 2.6 (2.4-2.7); and both voiding and storage LUTS, 4.0 (3.4-4.8). Among the 11,327 men with any recorded LUTS and ED at the beginning of 2007, LUTS diagnosis preceded SD in 63.1% of patients by a mean of 4.8 years.

CONCLUSIONS

Prevalence of SD was significantly higher in the presence of either storage or voiding LUTS compared to men with no recorded LUTS. The diagnosis of LUTS preceded SD in the majority of cases. Further research into the interrelationships between functional problems of the genitourinary tract may have implications for current treatment approaches and future therapeutic developments.

Oral phosphodiesterase-5 inhibitors and sperm functions

This review aims to elucidate the possible effects of phosphodiesterase-5 (PDE5) inhibitors on sperm functions. PDEs hydrolyze cyclic nucleotides, and together with adenylyl and guanylyl cyclase, which catalyze the formation of cAMP and cGMP, regulate the levels of these second messengers in cells. cGMP-specific PDE5 is one of the PDEs that have been intensively studied because of its fundamental pharmacological relevance, as oral PDE5 inhibitors are used successfully in treating erectile dysfunction. In addition, they have shown diverse beneficial actions in different disease categories. Specific relevance of the cGMP system in reproductive functions has been recently proposed. Its use was shown to be devoid of effects on semen volume, concentration, sperm membrane integrity or sperm penetration assay. Most available studies demonstrated a significant increase in sperm motility and viability both in vivo and in vitro, which seems to be enhanced at low doses and reduced at high concentrations. Also, these molecules showed a role in capacitation and a debated one concerning acrosome reaction. However, due to the relative short period since the launching of oral PDE5 inhibitors, more investigations should be carried out in wider scales to assess their effect(s) on variant sperm function that could be beneficial as potential therapeutic approaches.

Oral phosphodiesterase type 5 inhibitors: nonerectogenic beneficial uses

INTRODUCTION

Phosphodiesterase type 5 (PDE5) hydrolyses cyclic guanylate monophosphate (cGMP) specifically to 5' GMP. PDE5 inhibitors were a breakthrough medication that addressed a previously unfulfilled medical need. They promoted vascular relaxation in the corpora cavernosa and penile erection during sexual stimulation. Sildenafil, vardenafil, and tadalafil were approved then introduced as effective treatments for male erectile dysfunction. This impact has stimulated academic, clinical, and industrial research.

AIM

To highlight the nonerectogenic beneficial uses of oral PDE5 inhibitors.

METHOD

A systematic review of published studies in this affair based on a Pubmed and medical subject heading databases search of all concerned articles.

MAIN OUTCOME MEASURES

Demonstrated beneficial as well as applicable uses of oral PDE5 inhibitors.

RESULTS

As chemical molecules, these drugs were shown to exert potential nonerectogenic beneficial effects. They showed efficacy as a useful adjunct in the management of pulmonary hypertension. Additional uses were extended to different utilities: essential hypertension, benign prostatic hyperplasia, gastrointestinal disorders, endothelial dysfunction, female sexual dysfunction, genital blood flow, exercise capacity, Raynaud's phenomenon, sperm motility, etc.

CONCLUSION

Exploring PDE5 inhibitors for their possible medical applications in diverse specialties seems to be beneficial in making use of these molecules for the welfare of humanity.

Vardenafil in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia

Alpha-blockers, the current common treatment for lower urinary tract symptoms (LUTS), are also used to treat bladder outlet obstruction (BOO), but the effect is not as clinically significant as in LUTS. All currently marketed phosphodiesterase type 5 (PDE5) inhibitors have recently been shown to significantly affect LUTS, although BOO-related efficacy has not been determined. Therefore, the extent of a causal relationship between LUTS and underlying benign prostatic enlargement (BPE) is questionable. LUTS may also be interpreted as symptoms related to detrusor overactivity, especially when no significant BOO is associated with BPE. Research is required to understand the efficacy of PDE5 inhibitors in LUTS but not in BOO. For vardenafil, nonclinical experiments and initial, preliminary clinical data suggest that the underlying effect may occur on the detrusor and not the prostate.

The relationship between erectile dysfunction and lower urinary tract symptoms and the role of phosphodiesterase type 5 inhibitors

CONTEXT

The relationship between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) and the potential interplay of phosphodiesterase type 5 inhibitors (PDE5-I) have clinical implications for both patient screening and treatment.

OBJECTIVE

To describe the current literature assessing the LUTS-ED relationship and the role of PDE5-I from both a basic science and clinical intervention perspective.

EVIDENCE ACQUISITION

We focused on data recently published (1990-2008) describing epidemiologic and mechanistic manuscripts of the LUTS-ED relationship with emphasis on papers involving PDE5-I-particularly those using level 1 evidence clinical trials. Base key words used included BPH, LUTS, ED, and phosphodiesterase inhibitors in combination with such secondary key words as nitric oxide, autonomic hyperactivity, Rho-kinase, atherosclerosis, and mechanism. We abstracted >200 articles and reviewed >100.

EVIDENCE SYNTHESIS

The large overlap of elderly men with both LUTS and ED likely stems from a cause-and-effect relationship. Thus far, four proposed mechanisms attempt to explain the relationship between LUTS and ED. Multiple studies showing that PDE5-I improved LUTS have been performed. Understanding the role of PDE5-I in the LUTS and ED relationship affects patient screening and treatment but also raises further research questions.

CONCLUSIONS

The future use of phosphodiesterase inhibitors as either prophylaxis or as a primary treatment for LUTS looms as a possibility and may not be limited to men.

Tadalafil administered once daily for lower urinary tract symptoms secondary to benign prostatic hyperplasia: a dose finding study

PURPOSE

Phosphodiesterase type 5 inhibitors are widely used to treat erectile dysfunction. Preliminary data have suggested phosphodiesterase type 5 inhibitor efficacy in men with lower urinary tract symptoms associated with clinical benign prostatic hyperplasia.

MATERIALS AND METHODS

After a 4-week placebo run-in period 1,058 men with benign prostatic hyperplasia lower urinary tract symptoms were randomly allocated to receive 12-week, once daily treatment with placebo or tadalafil (2.5, 5, 10 or 20 mg).

RESULTS

The International Prostate Symptom Score least squares mean change from baseline to end point was significantly improved for 2.5 (-3.9, p = 0.015), 5 (-4.9, p <0.001), 10 (-5.2, p <0.001) and 20 mg (-5.2, p <0.001) tadalafil compared to placebo (-2.3). International Prostate Symptom Score improvements at 4, 8 and 12 weeks were significant for all tadalafil doses and they demonstrated a dose-response relationship. Tadalafil (2.5 mg) significantly improved the International Prostate Symptom Score obstructive subscore and the International Index of Erectile Function-Erectile Function domain, the latter in sexually active men with a history of erectile dysfunction. Statistically significant improvements were noted for 5, 10 and 20 mg tadalafil compared to placebo, as assessed by the International Prostate Symptom Score irritative and obstructive subscores, International Prostate Symptom Score Quality of Life, Benign Prostatic Hyperplasia Impact Index (nonsignificant for 10 mg), Global Assessment Question and International Index of Erectile Function-Erectile Function domain. No statistically significant effect of treatment compared to placebo was noted for peak flow at any tadalafil dose. Treatment emergent adverse events were infrequent in all tadalafil groups.

CONCLUSIONS

Once daily tadalafil demonstrated clinically meaningful and statistically significant efficacy and it was well tolerated in men with benign prostatic hyperplasia lower urinary tract symptoms. Of the doses studied 5 mg tadalafil appeared to provide a positive risk-benefit profile.

Uroflowmetric assessment of acute effects of sildenafil on the voiding of men with erectile dysfunction and symptomatic benign prostatic hyperplasia

PURPOSE

To evaluate the acute effects of sildenafil (50 mg) on the micturation of men with erectile dysfunction (ED) and concomitant benign prostatic hyperplasia (BPH) with lower urinary tract symptoms (LUTS) using uroflowmetric parameters.

MATERIALS AND METHODS

A total of 68 male patients randomized into two groups (36 treatment, 32 control groups) with International Prostate Symptom Score (IPSS) greater than 7 and International Index of Erectile Dysfunction-erectile function domain score lower than 26 were enrolled in the study. Patients in the treatment group received a single dose of 50 mg of oral sildenafil. Patients in the control group received no treatment. Prevoiding urine volumes determined ultrasonographically and voided urine volumes were also recorded. Statistical comparisons were made with the use of analysis of variance (ANOVA).

RESULTS

Mean ages were similar between treatment and control groups (60.4 +/- 9.8 and 58.6 +/- 8.3 years, respectively, P = 0.430). In the treatment group the maximum and average flow rates increased significantly (Q (max) from 15.6 +/- 6.8 cc/s to 19.3 +/- 7.2 cc/s, P < 0.0001; Q (avg) from 7.3 +/- 3.0 cc/s to 9.1 +/- 3.0 cc/s, P < 0.0001) with sildenafil administration, while other parameters studied remained unchanged.

CONCLUSION

Despite the limitations of variations of uroflowmetry, this study showed that sildenafil improves Q (max) and Q (avg) in patients suffering from ED with concomitant BPH-LUTS. Long-term studies are needed to evaluate the effects on IPSS, side effects, and drug interactions.

Comparative efficacy assessment of tamsulosin vs. tamsulosin plus tadalafil in the treatment of LUTS/BPH. Pilot study

INTRODUCTION

The high incidence of erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) in aging men and the same pathophysiology make probable to treat both disorders with the same treatment. Numerous authors evaluated the actions of PDE5i in improving the LUTS/(benign prostate hyperplasia) BPH.

AIM

To assess the efficacy and safety of tamsulosin 0.4 mg/day vs. tamsulosin 0.4 mg/day plus tadalafil 20 mg/day in patients with LUTS in a crossover design study.

MAIN OUTCOMES MEASURES

International Prostate Symptoms Score (IPSS), IPSS Quality of Life (IPSS-QOL), maximum flow rate (Qmax), post-void residual volume (PVR), International Index of Erectile Function-Erectile Function Domain (IIEF-EF), Global Assessment Quality (GAQ). For the statistical analysis, a Tukey-Kramer multicomparison test was used.

METHODS

A randomized, double-blind, crossover study was conducted from September 2007 to February 2008 in one center. Thirty men, older than 50 years old, with a history of LUTS/BPH of at least 6 months, were randomized into two groups to receive tamsulosin 0.4 mg/day vs. tamsulosin 0.4 mg/day plus tadalafil 20 mg/day for 45 days, and then switched to the other treatment mode for other 45 days.

RESULTS

Twenty-seven patients completed the study. Improvements of IPSS score and IPSS-QOL were significant with both treatments but greater with the drug combination. Both regimens similarly improved the Qmax and decreased the PVR volume from baseline (P < 0.001) with no significant differences between tamsulosin alone vs. tamsulosin and tadalafil (P > 0.05). The IIEF improved with tamsulosin plus tadalafil (P < 0.001) but not with tamsulosin alone (P > 0.05). The GAQ showed that all patients preferred the combination scheme. Both treatments were well tolerated. CONCLUSION; Tamsulosin 0.4 mg/day plus tadalafil 20 mg/day was more effective than tamsulosin 0.4 mg/day alone to improve LUTS and erectile dysfunction and was also well tolerated. Large-scale, randomized, placebo-controlled studies are needed to further assess the long-term safety and effectiveness of these agents in treating LUTS/BPH with or without ED.

The nitric oxide pathway in the human prostate: clinical implications in men with lower urinary tract symptoms

To date, there is an increasing interest in the nitric oxide (NO) pathway as a potential pharmacological target to treat male lower urinary tract symptomatology (LUTS). In the transition zone of the human prostate, a dense nitrinergic innervation has been shown of the fibromuscular stroma, glandular epithelium and blood vessels. The expression of key proteins of the NO pathway, such as the endothelial and neuronal nitric oxide synthase (eNOS, nNOS), cGMP-degrading phosphodiesterase type 5 (PDE5) and cGMP-binding protein kinase (cGK), has also been demonstrated. The hypothesis that an impaired NO/cGMP-signaling may contribute to the pathophysiology of benign prostatic hyperplasia (BPH) is supported by the results from randomized, placebo-controlled clinical studies, indicating that NO donor drugs and PDE5-inhibitors sildenafil, tadalafil and vardenafil may be useful to treat storage and voiding dysfunctions resulting from LUTS in men. Thus, given a potential role of the NO-pathway in the prostate and/or in other parts of lower urinary tract (e.g. bladder), the enhancement of the NO signaling by NO donor drugs, PDE5 inhibitors or activators of the soluble guanylyl cyclase (sGC) may represent a new therapeutic strategy for the treatment of LUTS. This review serves to focus on the role of NO and the NO-dependent signaling in the control of smooth muscle function in the human prostate. Results from clinical trials in men with LUTS/BPH are also discussed.

Sildenafil citrate improves erectile function and lower urinary tract symptoms independent of baseline body mass index or LUTS severity

OBJECTIVES

To evaluate the body mass index (BMI) and lower urinary tract symptom (LUTS) severity on treatment response to sildenafil in men with erectile dysfunction (ED) and moderate to severe LUTS associated with benign prostatic hyperplasia.

METHODS

A post hoc analysis of data from a 12-week, double-blind, placebo-controlled study of sildenafil (50 mg once daily titrated to 100 mg once daily) was conducted. The BMI categories were obese (> or = 30 kg/m(2)), overweight (> or = 25 to < 30 kg/m(2)), and normal weight (< 25 kg/m(2)). ED was defined as a score of < or = 25 on the erectile function domain of the International Index of Erectile Function, and LUTS was defined by an International Prostate Symptom Score of > or = 12. The maximal urinary flow rate was determined by uroflowmetry.

RESULTS

Patients receiving sildenafil (n = 189) had a significant improvement in the erectile function domain scores of the International Index of Erectile Function (P < .0001 vs placebo, n = 180), which did not vary across BMI groups. A greater improvement in LUTS score was observed with sildenafil compared with placebo for men with severe LUTS (-8.6 vs -2.4, P < .0001) than in men with moderate LUTS (-3.6 vs -1.7, P = .06). Also, the improvement in LUTS scores was significant (P < or = .02) for men taking sildenafil independent of BMI (obese, -8.9 vs -5.4; overweight, -7.3 vs -3.2; normal weight, -7.1 vs -0.84). No difference was found among the treatment groups in the change from baseline maximal urinary flow rate across all LUTS and BMI categories (range 4.5 to -4.2 mL/s).

CONCLUSIONS

The results of our study have shown that daily dosing with sildenafil improved ED and LUTS independent of baseline LUTS severity or BMI.

Lower urinary tract symptoms and its potential relation with late-onset hypogonadism

The study of the health status of the aging male takes presently a more integrative approach and it appears that ailments typical of male aging, such as lower urinary tract symptoms (LUTS), (visceral) obesity, metabolic syndrome and erectile failure are significantly interrelated. A common denominator of the above ailments is lower-than-normal testosterone levels occurring in a significant proportion of elderly men. This review addresses the potential connections between LUTS and late-onset hypogonadism. In animal studies there appear to be androgen and estrogen receptors in the urothelium and smooth muscle cells of the urethra and bladder of the rat and rabbit, as well as in the neurons in the autonomic ganglia of the prostatic plexus of the male rat. Upon castration electrically evoked relaxations of the smooth muscle of the prostatic urethra were decreased. There is a Rho-kinase activation/endothelin pathway; possibly involved in the increased smooth muscle activity found in both LUTS/benign prostate hyperplasia. Nitric oxide (NO) appears to have a smooth muscle relaxing effect in the urogenital organs. Studies in humans have convincingly shown that phosphodiestererase inhibitors have a beneficial effect on LUTS. More intervention studies should be undertaken to test the clinical validity of the theoretically plausible interrelationship between LUTS and late-onset hypogonadism.

Product-related research: how research can contribute to successful life-cycle management

Declining productivity with decreasing new molecular entity output combined with increased R&D spending is one of the key challenges for the entire pharmaceutical industry. In order to offset decreasing new molecular entity output, life-cycle management activities for established drugs become more and more important to maintain or even expand clinical indication and market opportunities. Life-cycle management covers a whole range of activities from strategic pricing to a next generation product launch. In this communication, we review how research organizations can contribute to successful life-cycle management strategies using phosphodiesterase 5 inhibitors as an example.

Common approach to managing lower urinary tract symptoms and erectile dysfunction

The present paper serves as a review of the associations between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED), with a focus on common and combined pathways for treatment. LUTS and ED are common conditions seen in general urologic practice. Research has started to establish epidemiologic and pathophysiologic links between the two conditions and a strong association confirmed across multiple studies. Men seeking care for one condition should always be interviewed for complaints of the other condition. Proposed common pathways include alpha-1 adrenergic receptor imbalance, Rho-kinase overactivity, endothelial cell dysfunction and atherosclerosis-induced ischemia. Medical therapy has replaced surgery as the first-line treatment for LUTS in most patients, with the incorporation of alpha-adrenergic receptor antagonists (alpha-ARAs) and 5-alpha-reductase inhibitors (5-ARIs) into everyday practice. Treatment with alpha-ARAs contributes to some improvement in ED, whereas use of 5-ARIs results in worsened sexual function in some patients. Phosphodiesterase-5 (PDE-5) inhibitors have revolutionized the treatment of ED with a simple oral regimen, and new insights demonstrate a benefit of combined use of PDE-5 inhibitors and alpha-ARAs. The mechanisms of action of these medications support these observed benefits, and they are being studied in the basic science and clinical settings. In addition, novel mechanisms for therapy have been proposed based on clinical and research observations. The minimally invasive and surgical treatments for LUTS are known to have adverse effects on ejaculatory function, while their effects on erectile function are still debated. Much remains to be investigated, but it is clear that the associations between LUTS and ED lay the foundation for future therapies and possible preventative strategies.

Alfuzosin 10 mg once daily for treating benign prostatic hyperplasia: a 3-year experience in real-life practice

OBJECTIVES

To assess the 3-year efficacy and safety of the selective alpha(1)-blocker alfuzosin at 10 mg once daily in men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) in 'real-life practice'. The influence of treatment response on the risk of acute urinary retention (AUR) and BPH-related surgery was also analysed.

PATIENTS AND METHODS

In all, 689 European men (mean age 67.6 years) were enrolled by general practitioners in a 3-year open-label study with alfuzosin at 10 mg once daily. They were asked to complete the International Prostate Symptom Score (IPSS), its eighth question (bother score), and the Danish Prostatic Symptom Score for sexual function (DAN-PSSsex). Efficacy was analysed at the endpoint in the intent-to-treat population. The impact of baseline variables (age, PSA level, IPSS and bother severity) and dynamic variables (IPSS worsening of >or=4 points and bother at the last available assessment under treatment) on the risk of AUR and BPH-related surgery was evaluated.

RESULTS

With alfuzosin, IPSS improved by 6.4 points (-33.4%) from baseline (P < 0.001), reaching >or=3 points and >6 points in 71.3% and 47.2% of men, respectively. There were also significant (P < 0.001) improvements from baseline in nocturia (-0.8, -25.5%), bother score (-1.7, -40.7%) and DAN-PSSsex weighted scores with treatment. Symptom relief was rapid and maintained over 3 years. Overall, 78 men (12.4%) had an IPSS worsening of >or=4 points, 16 (2.6%) had AUR, and 36 (5.7%) required BPH-related surgery. Symptom deterioration during treatment and high baseline PSA values were the best predictors of AUR and BPH-related surgery. Alfuzosin was well tolerated, dizziness being the most frequent adverse event (4.5%) possibly related to vasodilatation. Ejaculatory disorders were uncommon (0.4%). Changes in blood pressure remained marginal, including in men aged >or=65 years and those receiving antihypertensive agents.

CONCLUSION

Alfuzosin administered for 3 years at 10 mg once daily in real-life practice is effective and well tolerated. High PSA values and symptom worsening under treatment appear the best predictors of AUR and BPH-related surgery in the long term. Treatment with alfuzosin might thus help to identify patients at risk of LUTS/BPH progression in order to optimize their management.

Lower urinary tract symptoms and sexual dysfunction: a common approach

Alpha(1)-adrenergic blockers (alpha(1)-blockers) are considered the most effective monotherapy for lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia. Phosphodiesterase type-5 (PDE-5) inhibitors are the first-line treatment for erectile dysfunction (ED). As LUTS and ED are strongly linked, co-prescription of both drug classes is likely to increase. Interaction studies have confirmed that tadalafil, a long-acting PDE-5 inhibitor, has only marginal effects on blood pressure when co-administered with the selective alpha(1)-blockers, alfuzosin or tamsulosin. alpha(1)-blockers show an incidence of ED similar to placebo; they may even have some benefit on sexual function in men with concomitant LUTS and sexual dysfunction, with the exception of tamsulosin which causes anejaculation. On the other hand, PDE-5 inhibitors have a beneficial effect on LUTS. These agents are likely to act via different mechanisms of action, providing the rationale for combining them to treat LUTS and ED. Indeed, alfuzosin and tadalafil show an additive relaxant effect on human detrusor muscle, human prostate tissue and human corpus cavernosum in vitro. A pilot study also suggests that daily intake of alfuzosin 10 mg and sildenafil 25 mg is well tolerated and may be more effective than monotherapy to improve LUTS and ED. Further research is warranted to establish the value of this combination therapy in LUTS and ED.

Alpha1-adrenoceptor subtypes and lower urinary tract symptoms

Benign prostatic hyperplasia (BPH) is a common cause of urinary outflow obstruction in aging men leading to lower urinary tract symptoms (LUTS). alpha(1)-Adrenoceptors (alpha(1)ARs) antagonists (blockers) have become a mainstay of LUTS treatment because they relax prostate smooth muscle and decrease urethral resistance, as well as relieving bladder LUTS symptoms. A review of key recent clinical trials suggests new insights into the role of specific alpha(1)AR subtypes in the treatment of LUTS.

Identifying patients with benign prostatic hyperplasia through a diagnosis of, or treatment for, erectile dysfunction

OBJECTIVE

Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) associated with benign prostate hyperplasia (BPH) are highly correlated. This study examined rates of screening, diagnosis, and treatment of BPH/LUTS among men seeking care for ED.

RESEARCH DESIGN AND METHODS

This was a retrospective US claims data analysis (1999-2004) evaluating men > or = 40 years old with a new diagnosis of or prescription medication for ED. Multivariate analyses were used to examine times to screening, diagnosis, and treatment.

RESULTS

81 659 men with ED were identified (mean age 57 years). The baseline prevalence of recorded BPH was 1.5%. During the follow-up period (mean 2.2 years), 7.6% had documented BPH. Time to screening was shorter among patients seeing urologists (121.1 days) compared with those seeing primary-care physicians (282.2 days). Controlling for demographic and clinical characteristics, patients who saw a urologist were more likely to be screened (OR: 2.4, p < 0.0001), diagnosed with BPH (OR: 1.8, p < 0.0001), and treated (OR: 1.3, p < 0.0001), relative to patients seeing other providers. Men aged 75 and over were 43% less likely to be screened (p < 0.0001), but 5.4 times more likely to be diagnosed with BPH (p < 0.0001) and 5.3 times more likely to be treated (p < 0.0001) compared with men aged 40-49.

CONCLUSIONS

Screening for BPH appears less likely for men with ED who do not see a urologist. When screening does occur, it takes much longer with non-specialty providers. Patient age and provider specialty are key factors associated with screening, diagnosis, and treatment of BPH among men with ED.

A randomised, placebo-controlled study to assess the efficacy of twice-daily vardenafil in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) is associated with bothersome lower urinary tract symptoms (LUTS) and reduced patient quality of life (QoL). Phosphodiesterase (type) 5 (PDE5) inhibitors such as vardenafil are commonly used for the treatment of erectile dysfunction (ED), but have also been shown to improve the symptoms of BPH. This randomised, double-blind, placebo-controlled study investigated the effects of vardenafil on LUTS and QoL in men with BPH/LUTS, with or without concomitant ED.

METHODS

Men aged 45-64 yr with BPH/LUTS and an International Prostate Symptom Score (IPSS) > or =12 were randomised to receive either 10mg vardenafil or placebo twice daily. LUTS were assessed with the use of two primary efficacy parameters, IPSS score and maximum urinary flow rate (Qmax), as well as postvoid residual (PVR) urine volume; ED was measured with the use of the erectile function (EF) domain score of the International Index of Erectile Function (IIEF-EF); and QoL was assessed with the Urolifetrade mark QoL-9 questionnaire.

RESULTS

After 8 wk of treatment, there was a significant improvement in the IPSS total score in the vardenafil group compared with placebo (-5.9 and -3.6, respectively; p=0.0013). Nominally significant improvements in irritative and obstructive IPSS subscores (p=0.0017 and p=0.0081, respectively), EF (p=0.0001), and Urolife QoL-9 (p<0.0001) were also associated with vardenafil treatment. Qmax and PVR urine volume did not change significantly with treatment, although baseline values were already considered close to normal. Vardenafil was generally well tolerated, with most adverse events considered mild or moderate in severity.

CONCLUSIONS

Vardenafil treatment significantly improved LUTS, EF, and QoL in men with BPH/LUTS. Vardenafil may be considered a promising treatment option for men with symptoms secondary to BPH.

Combination of alfuzosin and tadalafil exerts in vitro an additive relaxant effect on human corpus cavernosum

INTRODUCTION

Phosphodiesterase type 5 (PDE5) inhibitors, such as tadalafil, are a first-line treatment for erectile dysfunction (ED). Nevertheless, some patients do not respond to this treatment. Clinical data suggest that the addition of alpha1-adrenoceptor blocker, such as alfuzosin, commonly prescribed for lower urinary tract symptoms suggestive of benign prostatic hyperplasia, may be of benefit. Aim. Evaluation of the effect of alfuzosin, tadalafil or the combination of both on human corpus cavernosum.

METHODS

Human cavernosal tissues were obtained from 10 patients undergoing penile surgery. Strips contractility was studied in organ baths. Concentration-response curves to tadalafil were generated on norepinephrine (NE, 1-10 microM)-precontracted strips in the presence of alfuzosin or vehicle. Frequency-response curves (FRC) to electrical field stimulation (EFS, 0-64 Hz, 3 ms, 10 seconds, 300 mA) were generated in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined. EFS (20 Hz, 1 ms, 10 seconds, 300 mM)-induced nitrergic relaxation on NE-precontracted strips was studied in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined.

MAIN OUTCOME MEASURES

Functional measurement of cavernosal smooth muscle relaxation in the presence of tadalafil and alfuzosin.

RESULTS

The relaxation induced by tadalafil (10(-10) to 10(-5) M) on precontracted strips was enhanced by alfuzosin at both 10(-8) and 10(-7) M. The combination of alfuzosin (3.10(-8) M) and tadalafil (10(-7) M) was more efficient to inhibit FRC-induced contractions than each compound alone. The combination of tadalafil (10(-6) M) and alfuzosin (10(-8) M) increased the relaxation induced by EFS and its effect was greater than tadalafil alone. In addition, the combination of tadalafil (10(-6) M) and alfuzosin (10(-7) M) prolonged EFS-induced relaxation to a greater extent than each compound alone.

CONCLUSIONS

In vitro, the combination of alfuzosin and tadalafil is more efficient than each compound alone to relax adrenergic tone or to enhance nitrergic relaxation of the human corpus cavernosum. Such a combination deserves further investigation in placebo-controlled studies to evaluate its benefit in ED patients who are not sufficiently improved by PDE5 inhibitors.

Phosphodiesterases (PDEs) and PDE inhibitors for treatment of LUTS

Lower urinary tract (LUT) smooth muscle can be relaxed by drugs that increase intracellular concentrations of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Both of these substances are degraded by phosphodiesterases (PDEs), which play a central role in the regulation of smooth muscle tone. The distribution and functional significance of PDE enzymes vary in different tissues of the LUT. Targeting specific PDE isoenzymes should thus allow organ selectivity. PDE 4 and 5 appear to predominate in the prostate, PDE 1 and 4 are thought to influence detrusor smooth muscle function, and PDE 5 may be functionally important in the urethra and vasculature. Studies on the use of PDE inhibitors to treat various LUT symptoms (LUTS), have yielded favorable results. Thus, positive effects of the PDE 5 inhibitors sildenafil and tadalafil on symptoms and quality of life in men with LUTS, erectile dysfunction, and BPH have also been demonstrated. These effects may be due to effects on cGMP signaling and/or modification of afferent input from bladder, urethral, and prostate tissue. This review gives an update on the distribution of PDEs in structures relevant for LUT function, and discusses how inhibition of these enzymes can contribute to beneficial effects on LUTS. Information for the review was obtained from searches of the PubMed database, and from the authors' files.

Phosphodiesterase-5 inhibitors for lower urinary tract symptoms in men

OBJECTIVE

To review the efficacy of phosphodiesterase-5 (PDE-5) inhibitors for the treatment of lower urinary tract symptoms in men.

DATA SOURCES

MEDLINE and International Pharmaceutical Abstracts were searched (1970-August 2007) using the terms phosphodiesterase inhibitor, sildenafil, vardenafil, tadalafil, lower urinary tract symptoms, and benign prostatic hypertrophy.

STUDY SELECTION AND DATA EXTRACTION

English-language clinical trials, case reports, and background material were evaluated for safety and efficacy data. References of reviewed articles were examined and used to identify additional sources.

DATA SYNTHESIS

Erectile dysfunction (ED) and lower urinary tract symptoms have numerous shared risk factors and are common in aging men. PDE-5 inhibitors may relax urinary tract smooth muscle tissue, which has led to interest in their utility for lower urinary tract symptoms. Six 12 week clinical trials were identified. Three uncontrolled trials (N = 168) examined the effects of on-demand sildenafil ED dosing on lower urinary tract symptoms. The 2 largest trials found that, the greater the ED response, the larger the reduction in lower urinary tract symptoms. A single prospective placebo-controlled trial (N = 369) studied sildenafil 100 mg daily in men with ED and lower urinary tract symptoms. Lower urinary tract symptoms improved significantly in the sildenafil group; patients with the worst lower urinary tract symptoms experienced the greatest benefits. An open-label trial (N = 62) compared daily sildenafil 25 mg, alfuzosin 10 mg, or sildenafil 25 mg plus alfuzosin 10 mg on ED and lower urinary tract symptoms. Combination therapy resulted in greater improvements in ED and lower urinary tract symptoms and urinary flow than did either drug alone. The effects of daily tadalafil 20 mg were studied in 281 men with lower urinary tract symptoms independent of ED. Tadalafil produced statistically significant but clinically modest improvements in lower urinary tract symptoms when compared with placebo.

CONCLUSIONS

PDE-5 inhibitors consistently produced modest reductions in lower urinary tract symptoms. Further studies are needed to fully elucidate the efficacy, cost effectiveness, safety, and appropriate place in therapy of PDE-5 inhibitors. At this time, data are insufficient to routinely recommend chronic use of PDE-5 inhibitors for lower urinary tract symptoms in men.

Daily Administration of Phosphodiesterase Type 5 Inhibitors for Urological and Nonurological Indications

OBJECTIVES

Although the discovery of phosphodiesterases (PDEs) was made soon after the identification of cyclic adenosine monophosphate nearly half a century ago, their true importance in medicine has taken many decades to be realised. The recognition of the important role PDE enzymes play and the impact of altering intracellular cyclic nucleotide levels became significant for most urologists and clinicians in the early 1990s with the discovery of sildenafil, a PDE5 inhibitor (PDE5-I). Once approved around the world, on-demand use of PDE5-Is became the gold standard. Recently, the potential beneficial effects of PDE5-Is on the pulmonary, vascular, and other systems has led to examination of alternative dosing regimens. In this review, we have synthesised the available published peer-reviewed literature to provide a critical contemporary view of evolving indications for PDE5-Is and how alternative dosing regimens may impact on sexual and other functions.

METHODS

MEDLINE search of all peer-reviewed English literature for the period 1990-2007.

RESULTS

The plethora of articles detailing potential uses of PDE5-I in multiple fields of medicine was uncovered. Use of alternative dosing regimens shows great promise across a number of clinical indications, including post-radical retropubic prostatectomy, pulmonary hypertension, endothelial dysfunction, and salvage of on-demand PDE5-I nonresponders.

CONCLUSIONS

Use of PDE5-I on a daily basis may evolve into a major form of drug administration both for men with erectile dysfunction and for those with a myriad of other conditions shown to benefit from this approach.