Tadalafil for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia: pathophysiology and mechanism(s) of action

Systematic review and meta-analysis on phosphodiesterase 5 inhibitors and α-adrenoceptor antagonists used alone or combined for treatment of LUTS due to BPH

The aim of this systematic review is to determine the comparative effectiveness and safety of phosphodiesterase 5 inhibitors (PDE5-Is) and α-blockers used alone or combined for the treatment of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). An electronic search of PubMed, Cochrane Library and Embase up to January 2014 was performed to identify randomized controlled trials comparing the efficacy and safety of PDE5-Is and α-blockers for treatment of lower urinary tract symptoms due to benign prostatic hyperplasia, which assessed IPSS score, maximum flow rate, postvoided residual urine, quality of life and Erectile Function (IIEF) score as outcomes. Data were analyzed by fixed or random effect models using Cochrane Collaboration review manager software. A total of 12 studies were included. Our novel data demonstrated that there was a trend that α-blockers were more efficacious than PDE5-Is on decreasing IPSS score and increasing maximum flow rate. α-blockers were significantly more effective than PDE5-Is on reduction of postvoided residual urine with a mean difference of 3.67 (95% CI 1.56 to 5.77, P = 0.0006) and PDE5-Is showed greater effect than α-blockers on increasing IIEF score with a mean difference of 9.82 (95% CI 3.80 to 15.85, P = 0.001). In conclusion, our novel data demonstrated that PDE5-Is plus ABs ranked the highest on the improvement of LUTS/BPH. PDE5-Is monotherapy was also effective in this kind of disorder except less reduction of PVR than ABs. In addition, both combined- or mono-therapy were safe.

The impact of surgical treatments for lower urinary tract symptoms/benign prostatic hyperplasia on male erectile function: A systematic review and network meta-analysis

Lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH) is common in adult men and can impair erectile function (EF). It was believed surgical treatments for this illness can improve EF due to the relief of LUTS while they were also reported harmed EF as heating or injury effect. Current network meta-analysis aimed to elucidate this discrepancy.Randomized controlled trials (RCTs) were identified. Direct comparisons were conducted by STATA and network meta-analysis was conducted by Generate Mixed Treatment Comparison. Random-effects models were used to calculate pooled standard mean difference and 95% confidence intervals and to incorporate variation between studies.Eighteen RCTs with 2433 participants were analyzed. Nine approaches were studied as transurethral resection of the prostate (TURP), plasmakinetic resection of the prostate (PKRP), plasmakinetic enucleation of the prostate (PKEP), Holmium laser enucleation of the prostate (HoLEP), Holmium laser resection of the prostate (HoLRP), photoselective vaporization of the prostate (PVP), Thulium laser, open prostatectomy (OP), and laparoscopic simple prostatectomy (LSP). In direct comparisons, all surgical treatments did not decrease postoperative International Index of Erectile Function (IIEF)-5 score except PVP. Moreover, patients who underwent HoLEP, PKEP, Thulium laser, and TURP had their postoperative EF significantly increased. Network analysis including direct and indirect comparisons ranked LSP at the highest position on the variation of postoperative IIEF-5 score, followed by PKRP, HoLEP, TURP, Thulium laser, PKEP, PVP, HoLRP, and OP. In subgroup analysis, only PVP was found lower postoperative EF in the short term and decreased baseline group, whereas TURP increased postoperative IIEF-5 score only for patients with normal baseline EF. However, HoLEP and PKEP showed pro-erectile effect even for patients with decreased baseline EF and short-term follow-up. Our novel data demonstrating surgical treatments for LUTS/BPH showed no negative impact on postoperative EF except PVP. Moreover, HoLEP and PKEP were found pro-erectile effect for all subgroups. New technologies, such as LSP, PKRP, and Thulium laser, were ranked at top positions in the network analysis, although they had no pro-erectile effect in direct comparison due to limited original studies or poor baseline EF. Therefore, further studies and longer follow-up are required to substantiate our findings.

Treatment satisfaction among men with concurrent benign prostatic hyperplasia and erectile dysfunction treated with tadalafil or other phosphodiesterase type-5 inhibitor combinations

OBJECTIVE

Erectile dysfunction (ED) and benign prostatic hyperplasia (BPH) frequently co-occur in men aged ≥40, along with lower urinary tract symptoms (LUTS) secondary to BPH. Given little real-world evidence on treatment use or satisfaction with treatment for concurrent BPH/LUTS and/or ED, this study examined medication regimens and differences in satisfaction and health-related quality of life (HRQoL) across regimens among men with concurrent BPH and ED.

METHODS

A cross-sectional study was conducted using an Internet survey of participants recruited through an online panel. Respondents (N=736) included men (aged ≥40) who self-reported a diagnosis of both ED and BPH with prescription treatment in the past 3 months for both conditions. Treatment satisfaction (eg, convenience and ease of planning) and HRQoL (eg, International Prostate Symptom Score, sleep quality) were self-reported. Generalized linear models examined the association of regimen with treatment satisfaction and HRQoL, adjusting for covariates (eg, age and comorbidities).

RESULTS

Final analyses included participants (N=507) using: tadalafil once-daily monotherapy (22%), tadalafil for ED with an alternate BPH therapy (36%), or another phosphodiesterase type-5 inhibitor (PDE5-I) combination (41%). These groups represented the major categories of treatment regimens found in the sample, excluded participants with ambiguous regimens, and were aligned with current standard of care for BPH and ED. Overall, patients reported moderate levels of BPH and a moderate-to-severe degree of ED. Tadalafil monotherapy patients had higher treatment satisfaction scores and greater reported ease of treatment planning and convenience than PDE5-I combination patients. No significant intergroup differences were found on HRQoL.

CONCLUSION

A majority of patients (59%) took tadalafil alone or in combination for BPH/ED treatment. Tadalafil monotherapy patients reported greater treatment satisfaction than patients taking PDE5-I combination therapy. Higher satisfaction for both effectiveness and convenience of once-daily tadalafil may inform both patient and clinician decisions regarding pharmacotherapy regimens.

A Meta-Analysis of Long- Versus Short-Acting Phosphodiesterase 5 Inhibitors: Comparing Combination Use With α-Blockers and α-Blocker Monotherapy for Lower Urinary Tract Symptoms and Erectile Dysfunction

Purpose:

Combination therapy with an α-1-adrenergic blocker and phosphodiesterase type 5 inhibitors (PDE5Is) has shown improvements in lower urinary tract symptoms (LUTS) with negligible side effects. Nonetheless, decisive advantages in symptom improvement were insufficient, and there were no clinical differences between long- or short-acting PDE5Is in combination with combination medication.

Methods:

To review the studies on α-1-adrenergic blocker monotherapy and combination therapy with long vs. short-acting PDE5Is in their use in LUTS and erectile dysfunction (ED). A search of the MEDLINE, Embase, Cochrane Library, and KoreaMed databases was conducted from 2000 to 2014 using combinations of the relevant terms. Among the 323 relevant references discovered, 10 were selected for meta-analysis. The data showed that 616 men received combination therapy (PDE5Is with α-1-adrenergic blockers) or α-1-adrenergic blocker monotherapy.

Results:

Meta-analysis of the combination therapy showed it was more effective than α-blockers in improving symptoms, with a mean International Prostrate Symptom Score change difference of –1.93 while those of the long- vs. short-acting PDE5I were –2.12 vs. –1.70. Compared to maximum flow rate (Qmax) value with monotherapy, the Qmax increased more with the combination therapy (mean difference of 0.71) while change values were 0.14 and 1.13 for the long- and short-acting PDE5Is, respectively. Residual urine decreased more with the combination therapy than it did with α-1-adrenergic blocker monotherapy with a mean difference of –7.09 while the mean residual urine change values for long- vs. short-acting PDE5Is were –18.83 vs. –5.93. The International Index of Erectile Function value increased by 3.99, 2.85, and 4.85 following combination therapy, and therapy with long- and short-acting PDE5Is.

Conclusions:

Our meta-analysis suggests that PDE5Is can significantly improve LUTS in men with benign prostatic hyperplasia/ED. Furthermore, combination PDE5I and α-1-adrenergic blocker could be a more effective treatment than α-1-adrenergic blocker monotherapy, and the differences between long and short-acting agents were minimal.

Phosphodiesterase Type 5 Inhibitor and Erectile Dysfunction in Lower Urinary Tract Symptoms

Benign prostatic hyperplasia (BPH) is one of the most common diseases in older men and mostly induces lower urinary tract symptoms (LUTS). Multiple studies have shown that BPH inducing LUTS are intensely correlated with erectile dysfunction (ED) and that severity of LUTS was proportional to ED severity. Although a direct causal relationship has not been clarified, a tentative pathophysiology has been suggested to interpret the relationship between two disorders. Androgen plays an important role in the maintenance of the functional and structural integrity of the lower urinary tract and penis. Low testosterone, especially free testosterone, worsened detrusor overactivity and replacement of testosterone improved LUTS in the hypogonadal BPH patients. Nitric oxide synthase and nitric oxide are decreased in the transition zone of the hyperplastic prostate but phosphodiesterase types 4, 5, 11 are prominent in transition zone of hyperplastic prostate. Phosphodiesterase type 5 (PDE5) inhibitor with a long half-life could obtain the desired effect; therefore, tadalafil and undenafil frequently have been used to evaluate the effects in the two disorders. In clinical trials, tadalafil showed improvement of BPH-induced LUTS, but few of the studies showed a significant improvement on uroflowmetry. PDE5 inhibitors increase the concentration of cyclic guanosine monophosphate (cGMP) in plasma and smooth muscle, promoting erection of the penis, as well as relaxation of the bladder neck and prostate, leading to natural voiding. Sexual function and LUTS should be assessed and discussed with the patient when choosing the appropriate strategy and the patient's response to treatment should also be evaluated at the same time.

Impact of cardiovascular risk factors and related comorbid conditions and medical therapy reported at baseline on the treatment response to tadalafil 5 mg once-daily in men with lower urinary tract symptoms associated with benign prostatic hyperplasia: an integrated analysis of four randomised, double-blind, placebo-controlled, clinical trials

PURPOSE

The influence of cardiovascular risk factors/comorbidities on response to oral once-daily tadalafil 5 mg was explored in men with lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH).

METHODS

This post hoc analysis pooled data from four double-blind studies in which 1498 men with > 6-mo history of LUTS/BPH were randomised and received either once-daily placebo (n = 746) or tadalafil 5 mg (n = 752) for 12 weeks. Descriptive statistics were reported for changes in total International Prostate Symptom Score (IPSS), IPSS voiding and storage subscores, and IPSS quality-of-life (QoL) index. Treatment group differences by baseline clinical and cardiovascular factors and medical therapies were examined using analysis of covariance.

RESULTS

Tadalafil was effective in men with LUTS/BPH and cardiovascular risk factors/comorbidities except for patients receiving > 1 antihypertensive medication. Placebo-adjusted least squares (LS) mean improvements in total IPSS were -1.2 (95% CI: -2.5 to -0.0) in men taking > 1 antihypertensive medication vs. -3.3 (95% CI: -4.4 to -2.1) in men taking one medication (interaction p = 0.020). In addition, placebo-adjusted LS mean improvements in total IPSS were -0.2 (95% CI, -2.1 to 1.7) in men who reported use of diuretics vs. -2.8 (95% CI, -3.7 to -1.9) in men who reported taking other antihypertensive medications vs. -2.3 (95% CI, -3.2 to -1.5) in men who reported not using any antihypertensive drug (p-value for interaction = 0.053).

CONCLUSIONS

Once-daily tadalafil 5 mg improved LUTS/BPH, regardless of severity, in men with coexisting cardiovascular risk factors/comorbidities, except for patients with history of > 1 drug for arterial hypertension. Use of diuretics may contribute to patients' perception of a negated efficacy of tadalafil on LUTS/BPH. Comorbidities should be considered when choosing the optimal medicine to treat men with LUTS/BPH.

Do baseline estrogen and testosterone affect lower urinary tract symptoms (LUTS) prior to or after pharmacologic treatment with tadalafil?

Little is known about how total testosterone and estradiol-17β influence lower urinary tract symptoms (LUTS) in men with benign prostatic hypertrophy (BPH). We analyzed data from a subset of men aged ≥18 years randomized to tadalafil 5 mg once-daily or placebo who had ≥6 month history of LUTS and an International Prostate Symptom Score (IPSS)≥13 enrolled in one of three randomized, placebo-controlled tadalafil clinical trials (N = 958). Three specific aims were addressed, as follows: (i) To characterize enrolled men by treatment randomization and testosterone level; (ii) to assess cross-sectional associations of estradiol-17β, testosterone, and LUTS prior to treatment with tadalafil; and, (iii) to assess longitudinal associations between baseline estradiol-17β and testosterone and improvements or worsening of LUTS during a 12-week period of tadalafil or placebo administration. LUTS were assessed by total IPSS, IPSS voiding sub-score (IPSS-V) and IPSS storage sub-score (IPSS-S) for cross-sectional analyses, and change in total IPSS (ΔIPSS), ΔIPSS-V, and ΔIPSS-S between baseline and 12-week visit for longitudinal analyses. Correlation analyses and linear regression examined associations. Baseline testosterone was not significantly associated with IPSS. In contrast, estradiol-17β was inversely correlated with IPSS (r = -0.08; p < 0.05) and IPSS-S (r = -0.14; p < 0.05). Tadalafil treatment resulted in greater IPSS improvements in men with lower baseline estradiol-17β versus those with higher baseline estradiol-17β. Lower baseline estradiol-17β was significantly associated with modestly improved ΔIPSS-V (p = 0.04) and Δtotal IPSS (p = 0.05) but not with ΔIPSS-S, following treatment which may substantiate the role of bladder dysfunction because of nerve and smooth muscle changes in the bladder in addition to benign prostatic enlargement in LUTS. Circulating baseline testosterone did not predict ΔIPSS. Men with lower baseline estradiol-17β levels showed greater responsiveness to tadalafil 5 mg treatment than those with higher baseline estradiol-17β levels when responsiveness was measured using total IPSS and IPSS-V.

The Impact of Medical and Surgical Treatment for Benign Prostatic Hypertrophy on Erectile Function

There is a well-known link between treatment for lower urinary tract symptoms (LUTS) and erectile dysfunction. Surgical and medical management of LUTS all have side effect profiles which may affect erectile dysfunction, ejaculatory dysfunction, or libido. These should be taken into consideration during patient counseling. This article reviews the common side effects of the medical and surgical treatments of LUTS.

Tadalafil for lower urinary tract symptoms secondary to benign prostatic hyperplasia: a review of clinical data in Asian men and an update on the mechanism of action

Tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor, is approved worldwide for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH-LUTS). The purpose of this narrative review is to summarize the clinical data on tadalafil 5 mg once-daily, primarily focusing on Asian men with BPH-LUTS, and to update the current understanding of the mechanism of action underlying PDE5 inhibition. Findings from studies have demonstrated that PDE5 is highly expressed in the lower urinary tract and supporting vasculature, and that PDE5 inhibition potentially decreases smooth muscle cell proliferation in the prostate, relaxes smooth muscle in the prostate, bladder neck and supporting vasculature, increases blood perfusion to the lower urinary tract, and modulates bladder afferent nerve activity. A total of 11 larger, 12-week, double-blind, randomized, placebo-controlled studies of tadalafil, including four Asian studies, have been conducted globally, enrolling >3000 men with BPH-LUTS. In addition, two long-term (42- and 52-week) studies enrolled 394 Japanese and 428 North American men, respectively, with BPH-LUTS. Overall, tadalafil 5 mg once-daily resulted in significant improvements in the change from baseline to endpoint in total International Prostate Symptom Scores (IPSS), IPSS storage and voiding subscores, and IPSS quality of life index compared with placebo. Tadalafil was well tolerated and had a favorable safety profile. These findings support tadalafil 5 mg once-daily for treating men, including Asian men, with BPH-LUTS.

Melatonin and Its Role in Lower Urinary Tract Function: An Article Review

This article reviewed the results of studies done on animals that assessed effects of melatonin on bladder function. Melatonin does not change strip relaxation on its own. However, pre-treatment with melatonin decreases contractile responses induced by phenylephrine, acetylcholine, bethanechol and KCl in a dose-dependent manner. The contractile responses induced by the direct calcium channel openers are significantly decreased by melatonin pre-treatment. It also binds to Ca(2+)-activated calmodulin, and prevents it from activating myosin light-chain kinase. It may have direct effects on ion channels which are responsible for regulating bladder contraction. Its other mode of action on bladder occurs via the brain GABAA receptor. Melatonin is an antioxidant. In bladder, treatment with melatonin prevents elevations in malondialdehyde levels, reverses changes in glutathione levels, and decreases myeloperoxidase levels compared with oxidative injury. It can normalize age induced bladder dysfunction through its antioxidant effects, inhibiting smooth muscle contractility directly and restoring impaired contractility via normalization of Ca(2+) handling and sensitizations pathways. It attenuates the severity of cystitis and inflammation. Mast cell proliferation and activation are increased in cystitis, but decrease by melatonin treatment. Also, there is a decrease in expression levels of pro-inflammatory cytokines after melatonin treatment.

Current use of phosphodiesterase inhibitors in urology

The causes of male erectile dysfunction (ED) are quite variable and are now commonly divided into etiologies such as ischemia, smooth muscle damage, or altered blood flow. Although varying rates of ED have been reported in literature, the number of men with ED is projected to increase worldwide by 2025 to approximately 322 million. Since the introduction of phosphodiesterase 5 (PDE5) inhibitors, there has been a paradigm shift in the treatment of ED because PDE5 inhibitors address a broad spectrum of etiologies for ED. Today, the American Urological Association recommends the use of three PDE5 inhibitors (sildenafil, tadalafil, and vardenafil) as a first-line therapy for the treatment of ED. This review evaluates the pharmacological mechanism of PDE5 inhibitors along with the impact and use of sildenafil, vardenafil, tadalafil, and avanafil. By increasing intracellular cGMP levels, PDE5 inhibitors have been shown to be effective in the treatment of ED. Through their effects on other cellular signaling pathways, PDE5 inhibitors have the potential for treating other urologic conditions as well. The use of PDE5 inhibitors can also be combined to produce a synergistic effect in conditions such as male hypogonadism and benign prostatic hyperplasia in addition to ED.

Elucidation of the Pattern of the Onset of Male Lower Urinary Tract Symptoms Using Cluster Analysis: Efficacy of Tamsulosin in Each Symptom Group

OBJECTIVE

To present a new grouping of male patients with lower urinary tract symptoms (LUTS) based on symptom patterns and clarify whether the therapeutic effect of α1-blocker differs among the groups.

METHODS

We performed secondary analysis of anonymous data from 4815 patients enrolled in a postmarketing surveillance study of tamsulosin in Japan. Data on 7 International Prostate Symptom Score (IPSS) items at the initial visit were used in the cluster analysis. IPSS and quality of life (QOL) scores before and after tamsulosin treatment for 12 weeks were assessed in each cluster. Partial correlation coefficients were also obtained for IPSS and QOL scores based on changes before and after treatment.

RESULTS

Five symptom groups were identified by cluster analysis of IPSS. On their symptom profile, each cluster was labeled as minimal type (cluster 1), multiple severe type (cluster 2), weak stream type (cluster 3), storage type (cluster 4), and voiding type (cluster 5). Prevalence and the mean symptom score were significantly improved in almost all symptoms in all clusters by tamsulosin treatment. Nocturia and weak stream had the strongest effect on QOL in clusters 1, 2, and 4 and clusters 3 and 5, respectively.

CONCLUSION

The study clarified that 5 characteristic symptom patterns exist by cluster analysis of IPSS in male patients with LUTS. Tamsulosin improved various symptoms and QOL in each symptom group. The study reports many male patients with LUTS being satisfied with monotherapy using tamsulosin and suggests the usefulness of α1-blockers as a drug of first choice.

Phosphodiesterase type 5 inhibitors for treating erectile dysfunction and lower urinary tract symptoms secondary to benign prostatic hyperplasia: A comprehensive review

Many men have coexistent erectile dysfunction (ED) and lower urinary tract symptoms secondary to benign prostatic hyperplasia (LUTS/BPH). Phosphodiesterase type 5 (PDE5) inhibitors are effective for treating both of these conditions independently. In this review we summarise the evidence supporting a link between ED and LUTS/BPH, and the results from key clinical studies related to the use of PDE5 inhibitors for treating both conditions. The results from these studies suggest that men who have both ED and LUTS/BPH, and are concerned about their sexual dysfunction, might benefit from single-agent, holistic treatment with a PDE5 inhibitor.

Clinical correlates of enlarged prostate size in subjects with sexual dysfunction

Digito-rectal examination (DRE) of the prostate provides useful information on the state of prostate growth and on the presence of suspected peripheral nodules. The aim of this study is to describe the clinical and biochemical correlates of finding an enlarged prostate size at DRE in subjects with sexual dysfunction (SD). A consecutive series of 2379 patients was retrospectively studied. The analysis was focused on a subset of subjects (n = 1823; mean age 54.7 ± 11.4) selected for being free from overt prostatic diseases. Several parameters were investigated. After adjusting for confounders, the presence of an enlarged prostate size at DRE was associated with a higher risk of metabolic syndrome (HR = 1.346 (1.129–1.759); P = 0.030), type 2 diabetes mellitus (HR = 1.489 (1.120–1.980); P = 0.006), increased LDL cholesterol (>100 mg dl⁻¹; HR = 1.354 (1.018–1.801); P = 0.037) and increased mean blood pressure (BP) values (HR = 1.017 (1.007–1.027) for each mmHg increment; P = 0.001). Accordingly, enlarged prostate size was also associated with a higher risk of arteriogenic erectile dysfunction (ED), as well as with other andrological conditions, such as varicocele and premature ejaculation (PE). PSA levels were significantly higher in subjects with enlarged prostate size when compared to the rest of the sample (HR = 3.318 (2.304; 4.799) for each log unit increment in PSA levels; P < 0.0001). Arteriogenic ED, according to different criteria, was also associated with increased PSA levels. In conclusion, our data support the need to examine prostate size either by clinical (DRE) or biochemical (PSA) inspection in subjects with SD, in order to have insights into the nature of the SD and the metabolic and cardiovascular (CV) background of the patient.

Combination of tadalafil and finasteride for improving the symptoms of benign prostatic hyperplasia: critical appraisal and patient focus

The evidence suggests that combination therapy for benign prostatic hyperplasia (BPH)-lower urinary tract symptoms (LUTS) using an α-blocker and a 5α-reductase inhibitor has become well accepted. The combination of daily tadalafil and an α-blocker has also demonstrated benefit. This paper addresses combination therapy with daily tadalafil and finasteride for the treatment of BPH-LUTS. Our results demonstrate that use of tadalafil and finasteride represents a logical extension of combination therapies. We analyze a landmark study by Casabé et al that demonstrates improved voiding symptoms as assessed by International Prostate Symptom Scores with a combination of tadalafil and finasteride compared with finasteride and placebo. Study patients had moderate to severe LUTS and prostate volumes >30 g. The additional benefit of improved erectile function as assessed by International Index of Erectile Function-erectile function domain scores with the addition of tadalafil was a secondary benefit. We propose that the ideal patient for combination therapy with tadalafil and finasteride has a prostate volume >30 g and desires additional benefit over monotherapy. For these men, improved erectile function without sexual side effects was a secondary benefit.

Mirodenafil prevents bladder dysfunction induced by chronic bladder ischemia in rats

Purpose:

To investigate the protective effect of mirodenafil on bladder function in a rat model of chronic bladder ischemia (CBI).

Methods:

Twenty-four Sprague-Dawley rats were randomized to three groups: untreated, sham-operated rats (control group); untreated, CBI model rats (CBI group); and CBI rats treated daily with 4 mg/kg mirodenafil (CBI+mirodenafil group). The CBI and CBI+mirodenafil groups underwent endothelial injury to the iliac arteries and were fed a 2% cholesterol diet after injury. Four weeks after surgery, the CBI+mirodenafil group started daily treatment with mirodenafil for four weeks. Eight weeks after surgery, continuous in vivo cystometry and in vivo organ bath studies of detrusor muscle strips were performed.

Results:

in vivo cystometry revealed that the rats in the CBI group had a significantly higher micturition frequency, lower bladder capacity, and lower compliance than the rats in the control and CBI+mirodenafil groups. The detrusor muscle strip study showed that the magnitude of the carbachol-induced contractile response was significantly lower in the CBI group compared to either the control or CBI+mirodenafil group. Addition of daily mirodenafil after induction of CBI decreased the contractile response, compared to untreated CBI rats. CBI induced submucosal fibrosis and degenerative changes in bladder walls, which was reversed by the addition of mirodenafil.

Conclusions:

Daily treatment with mirodenafil showed protective effects against bladder dysfunction resulting from CBI in rats.

Protective effect of tadalafil on the functional and structural changes of the rat ventral prostate caused by chronic pelvic ischemia

BACKGROUND

The etiology of Benign Prostatic Hyperplasia (BPH), a common among aged men, is not fully understood, however, in addition to androgens and aging, chronic ischemia has been proposed to contribute. Using an established rat model, we investigated whether chronic ischemia alters the structural and functional properties of the ventral rat prostate, and whether phosphodiesterase type 5 (PDE5) inhibitor (tadalafil) may have a protective action.

METHODS

Adult male Sprague-Dawley rats were divided into control, arterial endothelial injury (AI), and AI with tadalafil treatment (AI-tadalafil) groups. AI and AI-tadalafil groups underwent endothelial injury of the iliac arteries and received a 2% cholesterol diet following AI. AI-tadalafil rats were treated with tadalafil (2 mg/kg/day) orally for 8 weeks after AI. The control group received a regular diet. After 8 weeks, animals were sacrificed, and pharmacological and morphological studies on prostate tissues were performed.

RESULTS

Iliac arteries from AI rats displayed neo-intimal formation and luminal occlusion, an effect that was not prevented by tadalafil treatment. In the AI group, there was an obvious epithelial atrophy and a statistically significant increase in collagen fibers compared with the controls. Immunohistochemically, there was an up-regulation of smooth muscle α-actin (SMA). Contractile responses of prostate strips to KCl, electrical field stimulation (EFS), and phenylephrine (PE) were significantly higher after AI than in controls. Chronic treatment with tadalafil prevented the increase in contractile responses in ischemic tissue, and decreased the collagen deposition compared with the AI group.

CONCLUSIONS

In this rat model, chronic pelvic ischemia caused distinct functional and morphological changes in the prostate. Prostatic tissue from ischemic animals showed an increased contractile response to electrical and pharmacological stimulation, an increase in SMA, and an increased deposition of collagen. All these changes could be prevented by treatment with the PDE5 inhibitor, tadalafil, suggesting an involvement of cyclic guanosine monophosphate (cGMP).

Management of benign prostatic hyperplasia: role of phosphodiesterase-5 inhibitors

Several studies have highlighted a strong association between benign prostatic hyperplasia/lower urinary tract symptoms (BPH/LUTS) and erectile dysfunction (ED), particularly in elderly men. Many epidemiological trials, such as in vitro and in vivo studies, have reported the emerging role of metabolic syndrome, including abdominal obesity, impaired glucose metabolism, hypertriglyceridemia, low high-density lipoprotein cholesterol, and hypertension, in the development and progression of urinary and sexual symptoms. Moreover, many authors have focused their studies on the identification of all the shared pathogenetic mechanisms of LUTS/BPH and ED, including alteration of cyclic guanosine monophosphate and RhoA-ROCK pathways or vascular and neurogenic dysfunction. All these are potential targets for proposed phosphodiesterase type 5 inhibitors (PDE5-Is). Therefore, several trials have recently been designed to evaluate the role of PDE5-Is alone or in combination with conventional treatment for BPH, such as α-adrenergic blockers, in men affected by LUTS/BPH, with or without ED. Different PDE5-Is are in clinical use worldwide and currently six of them are licensed for the oral treatment of ED. All these compounds differ in pharmacokinetic factors, with influence on drug action, and subsequently in the overall safety and efficacy profile.

Phosphodiesterase inhibitors for treatment of voiding dysfunction: An overview of experimental and clinical evidence

Recently, the focus of the origin of lower urinary tract symptoms (LUTS) has change from the prostate to the bladder. Regardless of the underlying mechanism associated with the origin of LUTS, alpha-blockers continue to be the most common medicine prescribed to treat LUTS due to benign prostatic obstruction (BPO). The newest class of drug introduced to treat LUTS/BPO is phosphodiesterase inhibitors (PDEi) and the aim of this study was to review the role of PDEi in the treatment of LUTS/BPO. In this review, the first evidence was evaluated based on epidemiological studies followed by randomized clinical trials which provide evidence on the administration of PDEi in patients with LUTS/BPO. Experimental studies were also assessed to tentatively elucidate the association between LUTS and erectile dysfunction, and to elucidate the underlying mechanism. There is still controversy regarding the administration of PDEi due to the fear of detrusor impairment, response to acute administration, and the effects of PDEi combined with alpha-blockers. Following this review, we conclude that treatment of BPO/LUTS with PDEi is beneficial, based on experimental studies, strong evidence and the large number of randomized clinical trials confirming their efficiency.

Effect of short- and long-term sildenafil treatment on erectile dysfunction in rats with partial bladder outlet obstruction

AIM

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are frequent problems in older men worldwide. We evaluated the effect of short- and long-term sildenafil treatment on erectile function in rats with surgically induced partial bladder outlet obstruction (PBOO).

METHODS

A total of 60 male Sprague-Dawley rats were randomized in five groups: (1) control (sham-operated); (2) PBOO for 3 weeks; (3) PBOO for 6 weeks; (4) sildenafil (1.5 mg/rat/day) treated PBOO for 3 weeks; and (5) sildenafil treated PBOO for 6 weeks. We assessed erectile function by measuring intracavernous pressures (ICP), mean arterial pressure (MAP) and total ICP after cavernous nerve stimulation. Corpus cavernous smooth muscle (CCSM) strips were isolated and evaluated for relaxation responses using organ-bath preparation. Neuronal nitric oxide synthase (nNOS) expression was determined immunohistochemically.

RESULTS

Experimental PBOO at 3 and 6 weeks showed decreased erectile response based on ICP/MAP ratio, total ICP and decreased expression of nNOS, which returned to normal after prolonged daily treatment with sildenafil. CCSM strips from PBOO rats displayed reduced relaxation responses to both electrical field stimulation (EFS) and acetylcholine (ACh) as well as nNOS enzyme intensity when compared to untreated PBOO group, which was reversed by treatment with sildenafil for 6 weeks.

CONCLUSIONS

Daily sildenafil treatment prevents development of ED in PBOO rats in a time dependent manner. Further studies are needed to explore the effectiveness of sildenafil in patients with BPH/LUTS in association with ED.

Effect of tadalafil on male lower urinary tract symptoms: an integrated analysis of storage and voiding international prostate symptom subscores from four randomised controlled trials

BACKGROUND

The international prostate symptom score (IPSS) evaluates lower urinary tract symptoms (LUTS) in men with suspected benign prostatic hyperplasia (BPH); the total score does not differentiate between storage and voiding and is unevenly weighted (four questions [57%] on voiding, three questions [43%] on storage).

OBJECTIVE

To evaluate the relative contributions of storage and voiding IPSS subscores to total IPSS at baseline and in response to treatment with tadalafil.

DESIGN, SETTING, AND PARTICIPANTS

Integrated analysis of data from four placebo-controlled, 12-wk studies of tadalafil (5mg once daily) in 1499 men with LUTS/BPH.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Relationships between total IPSS and the storage and voiding subscores were assessed using graphical exploration and linear regression modelling. Linear modelling was performed for the baseline and endpoint and for changes in subscores. The optimal storage subscore to total IPSS (S:T) ratio for IPSS improvement was identified using nonparametric regression and gradient-descent optimisation.

RESULTS AND LIMITATIONS

The contribution of storage and voiding subscores at baseline and endpoint was 38.8% and 61.2%, and 39.2% and 60.7%, respectively. This intuitive 40:60 storage-to-voiding ratio was similar at baseline and endpoint by treatment group and for changes in subscores, but spanned the entire range for individuals. Changes in total IPSS were greatest for a storage subscore percentage contribution to total IPSS of 42.7%. There was no statistical association between S:T ratio (≥ 40% vs < 40%) at baseline and response to tadalafil. The main limitation was the use of unvalidated storage and voiding IPSS subscores.

CONCLUSIONS

A constant S:T ratio of 4:10 was observed at baseline and endpoint. The greatest effect on total IPSS was noted for an S:T percentage contribution of 42.7%. Tadalafil efficacy was unaffected by the level of storage dysfunction at baseline.

PATIENT SUMMARY

This analysis shows that for men with BPH, improvements during treatment with tadalafil apply to both storage and voiding symptoms at a constant ratio. The extent of storage dysfunction before treatment did not affect the response to treatment.

Comparative effectiveness of oral drug therapies for lower urinary tract symptoms due to benign prostatic hyperplasia: a systematic review and network meta-analysis

INTRODUCTION

Lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) are common in elder men and a number of drugs alone or combined are clinically used for this disorder. But available studies investigating the comparative effects of different drug therapies are limited. This study was aimed to compare the efficacy of different drug therapies for LUTS/BPH with network meta-analysis.

MATERIALS AND METHODS

An electronic search of PubMed, Cochrane Library and Embase was performed to identify randomized controlled trials (RCTs) comparing different drug therapies for LUTS/BPH within 24 weeks. Comparative effects were calculated using Aggregate Data Drug Information System. Consistency models of network meta-analysis were created and cumulative probability was used to rank different therapies.

RESULTS

A total 66 RCTs covering seven different therapies with 29384 participants were included. We found that α-blockers (ABs) plus phosphodiesterase 5 inhibitors (PDE5-Is) ranked highest in the test of IPSS total score, storage subscore and voiding subscore. The combination therapy of ABs plus 5α-reductase inhibitors was the best for increasing maximum urinary flow rate (Qmax) with a mean difference (MD) of 1.98 (95% CI, 1.12 to 2.86) as compared to placebo. ABs plus muscarinic receptor antagonists (MRAs) ranked secondly on the reduction of IPSS storage subscore, although monotherapies including MRAs showed no effect on this aspect. Additionally, PDE5-Is alone showed great effectiveness for LUTS/BPH except Qmax.

CONCLUSIONS

Based on our novel findings, combination therapy, especially ABs plus PDE5-Is, is recommended for short-term treatment for LUTS/BPH. There was also evidence that PDE5-Is used alone was efficacious except on Qmax. Additionally, it should be cautious when using MRAs. However, further clinical studies are required for longer duration which considers more treatment outcomes such as disease progression, as well as basic research investigating mechanisms involving PDE5-Is and other pharmacologic agents alleviate the symptoms of LUTS/BPH.

Lower urinary tract symptoms in men

Benign prostatic hyperplasia (BPH) is a highly prevalent and costly condition that affects older men worldwide. Many affected men develop lower urinary tract symptoms, which can have a negative impact on their quality of life. In the past, transurethral resection of the prostate (TURP) was the mainstay of treatment. However, several efficacious drug treatments have been developed, which have transformed BPH from an acute surgical entity to a chronic medical condition. Specifically, multiple clinical trials have shown that α adrenoceptor antagonists can significantly ameliorate lower urinary tract symptoms. Moreover, 5α reductase inhibitors, alone or combined with an α adrenoceptor antagonist, can reverse the natural course of BPH, reducing the risk of urinary retention and the need for surgical intervention. Newer medical regimens including the use of antimuscarinic agents or phosphodiesterase type 5 inhibitors, have shown promise in men with predominantly storage symptoms and concomitant erectile dysfunction, respectively. For men who do not adequately respond to conservative measures or pharmacotherapy, minimally invasive surgical techniques (such as transurethral needle ablation, microwave thermotherapy, and prostatic urethral lift) may be of benefit, although they lack the durability of TURP. A variety of laser procedures have also been introduced, whose improved hemostatic properties abrogate many of the complications associated with traditional surgery.

A review of the use of tadalafil in the treatment of benign prostatic hyperplasia in men with and without erectile dysfunction

Epidemiological data link erectile dysfunction (ED) and benign prostatic hyperplasia (BPH)-associated lower urinary tract symptoms (LUTS), two highly prevalent conditions in aging men, assuming common pathophysiological pathways. Tadalafil 5 mg once daily has been approved for the treatment of men with LUTS with or without comorbid ED. The aim of this review is to provide an overview of current knowledge on the epidemiological and pathophysiological links between ED and LUTS and to focus on tadalafil as a new treatment option in men with BPH-associated LUTS. A Medline search was completed using the Medical Subject Headings (MESH® keywords) 'prostatic hyperplasia' and 'phosphodiesterase inhibitors'. This search revealed 125 relevant references (entire Medline database up to 11 March 2014). The efficacy of tadalafil 5 mg once daily for the treatment of LUTS has been reported by several well-designed studies. Tadalafil improves significantly the total International Prostate Symptom Score (IPSS), the voiding and storage subscores, the IPSS Quality of Life (QoL) and the BPH Impact Index (BII). Its efficacy is irrelevant to the erectile function status of the patients. However, in the majority of these studies tadalafil is not associated with improvement in maximum urine flow or post-void residual volume (PVR). Its safety profile is well established and no new or unexpected adverse events other than those reported in ED studies have been recorded. Tadalafil is today a new treatment alternative to other established drugs for LUTS such as the α-adrenergic antagonists or 5α-reductase inhibitors. However, it is not just an alternative, since sexual adverse events associated with these drugs are avoided and tadalafil is the only drug that can treat both ED and LUTS at the same time.

Pharmacological treatment of chronic pelvic ischemia

Epidemiological studies have shown that lower urinary tract symptoms, including overactive bladder, commonly occur in both men and women, with an age-related increase in both sexes. Vascular endothelial dysfunction and urological symptoms are common in the metabolic syndrome; they also occur during the human ageing process and are independent risk factors for the development of atherosclerosis and hypertension. Pelvic arterial insufficiency may lead to impaired lower urinary tract perfusion and play an important role in the development of bladder dysfunction such as detrusor overactivity and overactive bladder. It seems reasonable, but has not been definitely established clinically, that chronic ischemia-related bladder dysfunction will progress to bladder underactivity. Studies in experimental models in rabbits and rats have shown that pelvic arterial insufficiency may result in significant bladder ischemia with reduced bladder wall oxygen tension, oxidative stress, increased muscarinic receptor activity, ultrastructural damage, and neurodegeneration. Several types of drug may be able to prevent some of these changes. Even if the α1-adrenoceptor blocker, silodosin, the phosphodiesterase type 5 inhibitor, tadalafil, the β3-α1-adrenoceptor agonist, mirabegron, and the free radical scavenger, melatonin, were unable to prevent the development of neointimal hyperplasia and consequent luminal occlusion in animal models, they all exerted a protecting effect on urodynamic parameters, and on the functional and morphological changes of the bladder demonstrable in vitro. The different mechanisms of action of the drugs suggest that many factors are involved in the pathogenesis of chronic ischemia-induced bladder dysfunction and can be targets for intervention. Since several of the agents tested are used clinically and effectively for relieving lower urinary tract symptoms, the results from animal models of chronic bladder ischemia seem to have translational value. Animal models may be of relevance for designing clinical studies to demonstrate if a certain drug may prevent progression of ischemia-related functional and morphological bladder changes.

Management options for the treatment of benign prostatic hyperplasia with or without erectile dysfunction: a focus on tadalafil and patient considerations

Lower urinary tract symptoms (LUTS) and erectile dysfunction increase with age. Several studies have identified a true association between these two disorders. Basic research studies have shown a significant decrease in the nitric oxide/cyclic guanosine monophosphate pathway with age that leads to decreased relaxation of the bladder wall and prostate and worsening LUTS. In this review article, we will focus on the potential use and clinical significance of phosphodiesterase-5 inhibitors in the treatment of LUTS secondary to benign prostate hyperplasia.

Advances in targeting cyclic nucleotide phosphodiesterases

Cyclic nucleotide phosphodiesterases (PDEs) catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants.

Effects of chronic treatment with cilostazol, a phosphodiesterase 3 inhibitor, on female rat bladder in a partial bladder outlet obstruction model

OBJECTIVE

To investigate whether bladder dysfunction after bladder outlet obstruction (BOO) could be altered by treatment with cilostazol, a phosphodiesterase 3 inhibitor (PDE3i).

METHODS

Twelve-week-old female Sprague-Dawley rats were divided into 5 groups: groups 1 and 2, sham-operated rats and groups 3-5, BOO rats. Group 1 and 3 rats were given normal diet, group 2 and 5 rats were given high-dose PDE3i diet, and group 4 rats were given low-dose PDE3i diet. PDE3i was given within diet from the day of surgery. Four weeks after BOO, the bladder was excised and dissected into 4 longitudinal strips for isometric organ-bath assay. Contractile responses of bladder strips to electrical field stimulation (EFS), carbachol, and potassium chloride (KCl) were determined for each group.

RESULTS

BOO induced a significant increase in bladder weight in groups 3-5 compared with groups 1 and 2. PDE3i treatment did not affect bladder weight in sham or BOO rats. Contractile forces in response to EFS, carbachol, and KCl in group 3 were about 20%-40% of those in group 1. Contractile responses to EFS or KCl in PDE3i-treated BOO rats were not significantly different from those in group 3. Only high dose of PDE3i treatment in BOO rats caused a statistically significant increase in the response to carbachol compared with group 3.

CONCLUSION

PDE3i has a small but significant protective effect on the contractile dysfunction induced by a 4-week BOO in rats, although the increase in bladder mass was not altered. PDE3i could be a useful protection against contractile dysfunction of the obstructed bladder.

Comparison of the efficacy of isosorbide mononitrate and doxazosin in the treatment of lower urinary tract symptoms and benign prostatic hyperplasia: a randomized clinical trial

OBJECTIVE

We aimed to compare the efficacy of isosorbide mononitrate and doxazosin in the treatment of lower urinary tract symptoms (LUTS).

PATIENTS AND METHODS

80 patients with LUTS were included in this randomized clinical study. All patients were evaluated with uroflowmetry, post-void residual (PVR) urine, prostate volume, International Prostate Symptom Score (IPSS), serum PSA, urinalysis and culture. 40 patients were prescribed doxazosin for 4 weeks, another 40 were prescribed isosorbide mononitrate for 4 weeks. Urologic re-evaluation was done at the end of the study.

RESULTS

74 patients completed the study. The mean age of patients was 59.6 ± 0.7 years, the mean PSA value was 1.7 ± 0.1 ng/ml and the mean prostate volume was 41.9 ± 1.7 ml. Doxazosin markedly improved IPSS (from 16.2 ± 0.7 to 9.5 ± 0.5), maximum urinary flow rate (from 10.9 ± 0.7 to 12.8 ± 0.6 ml/s) and PVR urine (from 68.1 ± 9.4 to 39.0 ± 4.4 ml) (p < 0.0001, p < 0.0001, p = 0.0004, respectively). Isosorbide only improved IPSS (from 16.5 ± 0.9 to 14.6 ± 0.8) (p = 0.032).

CONCLUSIONS

Daily administration of isosorbide does not seem to be an alternative to α-blocker therapy. Controlled, randomized novel studies are required to establish that whether nitric oxide donors are an effective alternative in LUTS treatment.

Erectile dysfunction in the elderly: an old widespread issue with novel treatment perspectives

Erectile dysfunction (ED) is one of the most common chronic diseases affecting men and its prevalence increases with aging. It is also the most frequently diagnosed sexual dysfunction in the older male population. A number of different diseases potentially worsening sexual function may occur in elderly people, together with polypharmacy. Related causes of ED are variable and can include arterial, neurogenic, hormonal, cavernosal, iatrogenic, and psychogenic causes. The aim of the present review was to examine the main aspects of erectile dysfunction going through epidemiology and pathophysiology and revise most of ED in elderly disabled men and in those affected with psychiatric disorders. Lastly we tried to focus on the main aspects of nonpharmacological and pharmacological treatments of ED and the recreational use in the elderly. Phosphodiesterase-5 inhibitors (PDE5-I) are commonly used for on-demand or chronic treatment of ED. It is widely known that PDE5-I have lower response rates in older men than in younger patients, but they have the advantages of ease of use and excellent safety profile, also in the elderly. The old and new PDE5-I as well as the alternative treatments for ED are extensively discussed.

Tadalafil 5 mg once-daily therapy for men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia: results from a randomized, double-blind, placebo-controlled trial carried out in Japan and Korea

OBJECTIVES

To gain further evidence on the efficacy, safety and tolerability of tadalafil 5 mg once-daily in Asian men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

METHODS

Japanese and Korean men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia were randomized to once-daily tadalafil 5 mg (n = 306) or placebo (n = 304) for 12 weeks.

RESULTS

A significantly greater improvement (P < 0.001) in total International Prostate Symptom Score for the change from baseline (week 0) to study end-point (week 12) was observed for tadalafil (-6.0) versus placebo (-4.5). Significantly greater improvements (P < 0.01) in total International Prostate Symptom Score for the change from baseline to weeks 4 and 8 were observed for tadalafil versus placebo. Significantly greater improvements (P < 0.05) in International Prostate Symptom Score voiding and storage subscores, and International Prostate Symptom Score Quality of Life Index were observed for the change from baseline to end-point for tadalafil versus placebo. Significantly greater improvements (P < 0.001) in urinary symptoms were observed for tadalafil versus placebo for both Patient and Clinician Global Impressions of Improvement. No new safety concerns were identified.

CONCLUSIONS

These findings confirm the efficacy and safety profile of tadalafil 5 mg once-daily in Asian men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.