Effect of terazosin on prostatism in men with normal and abnormal peak urinary flow rates

Precision medicine in the diagnosis and treatment of male lower urinary tract symptoms suggestive of benign prostatic hyperplasia

Male lower urinary tract symptoms (LUTSs) are highly prevalent in men and the incidence increases with aging. The pathophysiology of male LUTSs might be bladder outlet dysfunctions such as bladder neck (BN) dysfunction, benign prostatic obstruction, and poor relaxation of external sphincter and bladder dysfunctions such as detrusor overactivity (DO), detrusor underactivity, DO, and inadequate contractility. Male LUTSs include voiding and storage symptoms, and precision diagnosis should not be done based on the symptoms alone. Videourodynamic study provides a thorough look at the bladder and bladder outlet and can clearly demonstrate the underlying pathophysiology when the initial medication fails to relieve LUTS. Medical treatment should be given based on the underlying pathophysiology of LUTS, and surgical intervention to remove prostate should only be performed when a definite bladder outlet obstruction due to prostatic obstruction has been confirmed by invasive urodynamic study.

Alpha-blockers for the Treatment of Benign Prostatic Hyperplasia

Over the last 2 decades the evolution of alpha-blockers for lower urinary tract symptoms (LUTS)/benign prostatic hyperplasia (BPH) has been to preserve effectiveness, improve tolerability, and eliminate dose titration. Today, alpha-blockers represent the first-line treatment of most men with BPH whereby the primary objective is relief from bothersome LUTS.

Current consensus and controversy on the diagnosis of male lower urinary tract symptoms/benign prostatic hyperplasia

Traditionally, male lower urinary tract symptoms (LUTS) have been considered a synonym for benign prostate hyperplasia (BPH) because most male LUTS develops in aging men. Medical treatment should be the first-line treatment for BPH and surgical intervention should be performed when there are complications or LUTS refractory to medical treatment. Recent investigations have revealed that bladder dysfunction and bladder outlet dysfunction contribute equally to male LUTS. In the diagnosis of LUTS suggestive of BPH (LUTS/BPH), the following questions should be considered: Is there an obstruction? Are the LUTS caused by an enlarged prostate? What are the appropriate tools to diagnose an obstructive BPH? Should patients with LUTS be treated before bladder outlet obstruction is confirmed? This article discusses the current consensus and controversies in the diagnosis of LUTS/BPH.

Current consensus and controversy on the treatment of male lower urinary tract symptoms/benign prostatic hyperplasia

Lower urinary tract symptoms (LUTS) are highly prevalent in men and increase with age. Because LUTS are common among elderly men, they are usually considered synonymous with benign prostatic hyperplasia (BPH). Drugs should be the first-line treatment for BPH and surgical intervention should be performed only when there are complications or LUTS refractory to medical treatment. In addition to medical treatment, several minimally invasive therapies, such as thermal therapy, prostatic lift, laser evaporation, or laser enucleation techniques have been developed. Recent investigations have also revealed that bladder dysfunction such as detrusor overactivity and detrusor underactivity may also contribute to male LUTS. In the treatment of LUTS suggestive of BPH (LUTS/BPH), the following questions should be considered: Is there an obstruction? Are we treating BPH or LUTS? Can management targeting BPH reduce LUTS? Should patients with LUTS be treated before bladder outlet obstruction is confirmed? What is the role of transurethral resection of the prostate (TURP) nowadays? Will new techniques provide better outcomes than TURP? This article discusses the current consensus and controversies in the treatment of LUTS/BPH.

Emerging treatment options for benign prostatic obstruction

Benign prostatic obstruction (BPO) affects an increasing number of men with age. It can cause troublesome lower urinary tract symptoms, can have a negative impact on quality of life, and may be associated with significant morbidity. Currently available medication and surgical treatments are limited by adverse events, invasiveness, and patient compliance. This has driven research into the pathogenesis of benign prostatic hyperplasia and led to the development of novel pharmacological agents and minimally invasive therapeutic interventions. This review highlights emerging treatment options for BPO.

Videourodynamic Analysis of Pathophysiology of Men with Both Storage and Voiding Lower Urinary Tract Symptoms

OBJECTIVES

Lower urinary tract symptoms (LUTS) are highly prevalent among men; however, not all men with LUTS have urodynamically confirmed bladder outlet obstruction. Overactive bladder symptoms are often caused by bladder dysfunctions alone or in combination with bladder outlet obstruction. A detailed diagnosis to identify the causes of LUTS in men seems mandatory to correctly target different therapy to the various underlying pathologic features.

METHODS

A total of 1407 male patients referred for investigation of LUTS were included in this study. All patients had both storage and voiding symptoms. A videourodynamic study was performed for the diagnosis of bladder dysfunction and bladder outlet dysfunction. The videourodynamic results were also correlated with patient age and compared with the presenting symptoms.

RESULTS

The videourodynamic study revealed that of the 1407 patients with bladder dysfunction, 148 (10.5%) had increased bladder sensation, 724 (51.5%) had detrusor overactivity, 149 (10.6%) had detrusor underactivity, and 82 (5.8%) had a combination of detrusor overactivity and detrusor underactivity. The causes of bladder outlet dysfunction included bladder neck dysfunction in 19 patients (1.4%), benign prostatic obstruction in 413 (29.4%), urethral sphincter pseudodyssynergia in 30 (2.1%), and poor relaxation of urethral sphincter in 283 (20.1%).

CONCLUSIONS

The results of this study have indicated that LUTS can result from a complex interplay of pathophysiologic features that can include bladder dysfunction and bladder outlet dysfunction such as benign prostatic obstruction or poor relaxation of the urethral sphincter. About one third of men with LUTS who were older than 55 years of age had benign prostatic obstruction. Patients younger than 55 years old were more likely to have poor relaxation of the urethral sphincter as a likely cause of LUTS.

Comparison of tamsulosin and naftopidil for efficacy and safety in the treatment of benign prostatic hyperplasia: a randomized controlled trial

OBJECTIVES

To compare the efficacy and safety of two alpha1a/alpha1d adrenoceptor (AR) antagonists with different affinity for the alpha1AR subtypes, tamsulosin and naftopidil, in the treatment of benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Patients with BPH were randomized to receive either tamsulosin or naftopidil. The primary efficacy variables were the changes in the total International Prostate Symptom Score (IPSS), maximum flow rate on free uroflowmetry, and residual urine volume. The secondary efficacy variables were average flow rate, changes in the IPSS storage score, IPSS voiding score, and quality-of-life (QoL) Index score, from baseline to endpoint (12 weeks). Data on all randomized patients were included in the safety analyses for adverse effects and changes in blood pressure.

RESULTS

Of the 185 patients enrolled data for 144 who were eligible for inclusion in the efficacy analysis were analysed (75 from the tamsulosin and 69 from the naftopidil group). There was no significant difference in any variable at baseline between the groups. There were statistically significant improvements for all primary and secondary variables in both groups, except for residual urine in the tamsulosin group. However, there was no significant intergroup difference in the improvement of any efficacy variable between the groups. The adverse effects were comparable, with no significant differences in systolic and diastolic blood pressure after treatment in both groups.

CONCLUSIONS

This study suggests that naftopidil is as effective and safe as tamsulosin. Both drugs were effective in improving storage and voiding symptoms. However, there was no difference in clinical efficacy or adverse effects between the alpha1 AR antagonists with different affinity to alpha1 subtypes, alpha1a and alpha1d.

The effect of combined androgen ablation on the expression of alpha1A-adrenergic receptor in the human prostate

BACKGROUND

This study was designed to determine whether androgen ablation (AA) affects expression of alpha1A-adrenergic receptors (AR) in the human prostate.

METHODS

Concentrations of alpha1A-AR mRNA were determined in benign prostatic tissue from patients undergoing surgery after a 3-month course of combined androgen ablation (CAD) therapy with leuprolide and flutamide, and a matched group of untreated patients with clinical BPH.

RESULTS

Mean concentration of alpha1A-AR in the AA group was 0.53 +/- 0.53 SD (range 0.026-1.55) attomol/mg. Control mean was 0.29 +/- 0.22 SD (range 0.02-0.69; P = 0.3, two tailed t-test). Tissue composition did not statistically differ between the two groups. Expression of alpha1A-AR correlated with concentration of smooth muscle myosin heavy chain (SMMHC) (r = 0.84, P = 0.001). No significant differences were observed after adjusting for SMMHC content.

CONCLUSIONS

A 3-month course of CAD does not appear to have a significant effect on alpha1A-AR mRNA expression in the human prostate.

The use of alpha-adrenoceptor antagonists in lower urinary tract disease

alpha-adrenoceptor antagonists have traditionally been used in the treatment of hypertension but in recent years they have become increasingly common in the treatment of benign prostatic enlargement (BPE), where they reduce the 'dynamic' component of bladder outlet obstruction and appear to have additional actions to reduce irritative symptoms of the disease. Prazosin (Hypovase), Alza), doxazosin (Cardura), Pfizer), indoramin (Doralese), Wyeth-Ayerst Pharmaceuticals Inc.) and terazosin (Hytrin), Abbott Laboratories) are currently available in the UK for BPE but these agents have cardiovascular actions in a significant number of patients, inducing effects which must be considered adverse unless the patient also requires treatment for mild-to-moderate hypertension. The uroselective alpha-adrenoceptor antagonists tamsulosin (Flomax), Yamanouchi Pharmaceutical Co. Ltd.) and alfuzosin (Xatral), Sanofi-Synthelabo) have recently been introduced. These agents exert their selectivity via different mechanisms; selective tissue distribution for alfuzosin and alpha-adrenoceptor subtype selectivity for tamsulosin. The incidence of cardiovascular side effects for both drugs is similar to placebo. Several lines of evidence suggest that the alpha-adrenoceptor antagonists may relieve lower urinary tract (LUT) symptoms by other mechanisms additional to those which account for the reduction in bladder outlet obstruction. If correct, these agents may be of use in the treatment of other bladder conditions.

Subtype selective alpha1-adrenoceptor antagonists for the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is highly prevalent in the male population beyond the age of 60. Impairment of urinary flow due to prostate enlargement gives rise to symptoms of 'prostatism' that have a detrimental impact on the quality of life. The current trend in the management of symptomatic BPH favours pharmacotherapy as a first line option, while the number of surgical procedures being performed has experienced a steady decline during the last ten years. Among the pharmacological treatments, the use of alpha1-adrenoceptor blockers has demonstrated to be an effective treatment option for BPH. These agents reduce the adrenergic tone to the prostate and increase urinary flow, with a concomitant reduction of lower urinary tract symptoms. The alpha1-blockers currently approved include compounds such as alfuzosin, terazosin and doxazosin, originally developed for the treatment of hypertension, and more recently tamsulosin, an alpha1-subtype selective drug. The blockade of alpha1-adrenoceptors present in vascular smooth muscle is largely responsible for the most prominent side effects of current drugs, which can be severe and require patients dose titration. The limitation imposed by side effects naturally raises the possibility that complete blockade of prostatic alpha1 receptors is not attained at the maximum tolerated dose. The extensive efforts by the pharmaceutical industry towards the development of uroselective alpha1-blockers, is the subject of this review. Advances in the molecular cloning of genes encoding three alpha1-adrenoceptors led to the identification of the alpha1A-subtype as the predominant receptor responsible for the contraction of prostate smooth muscle. In preclinical animal models, selective alpha1A-antagonists have consistently been found to have minimal cardiovascular effects, thus providing a pharmacological rationale for uroselectivity. It has also become apparent, however, that uroselectivity can emerge in a poorly understood manner from the pharmacodynamic properties of compounds without alpha1A-subtype selectivity. Clinical experience with tamsulosin, an alpha1A/alpha1D selective drug, has failed to demonstrate a significant improvement in efficacy beyond that demonstrated for non-subtype selective alpha1-blockers, and gives support to the notion that alpha1A-selective antagonists might achieve greater efficacy for the treatment of BPH. Given the demonstrated uroselectivity of alpha1A-selective antagonists in preclinical models, it is anticipated that third generation alpha1-blockers will exhibit improved urinary flow efficacy and be better tolerated than tamsulosin. The extent to which the improvement in urinary flow will translate to the relief of symptoms of prostatism, however, remains to be demonstrated in randomised placebo-controlled clinical trials of alpha1A-selective antagonists.

Office evaluation of men with lower urinary tract symptoms

In the past decade, the symptom score has been considered the essential part of the evaluation of patients with lower urinary tract symptoms (LUTS). At the University of Wisconsin, the author's have stopped routine use of symptom scores because of their limited utility in dealing with the patient's concerns. Except from men electing invasive treatment, the authors do not serve the patients better with urodynamic testing either. Bothersomeness, not symptom score or objective measures is what drives the decision making process in benign prostatic hyperplasia (BPH) management. Generally, the authors now select patients for treatment according to the degree to which they are bothered by their LUTS.

The medical management of lower urinary tract symptoms and benign prostatic hyperplasia

Prostatism is a widely used term assigned to the symptom complex of older men with voiding dysfunction. The cause of the syndrome has routinely been ascribed to an enlarged prostate. More recent thinking recognizes that many men with such symptoms do not, in fact, have prostate enlargement or benign prostatic hyperplasia (BPH) and that such symptoms are not a surrogate for BPH. Such recognition is essential if cost effective medical management of lower urinary tract symptoms (LUTS) is to be achieved. Prostate volume has emerged as a key factor in the selection of medical therapy of LUTS and BPH not only regarding symptom relief but also to the newer concept of the prevention of disease progression and the avoidance of future adverse events in those men with true BPH. In the United States, medical management is now first line therapy for LUTS. The proper selection of therapy based on the patient's individual pathophysiologic characteristics is now made possible by many new recent studies within the medical literature.

Alpha1-adrenergic receptor subtypes in human detrusor

PURPOSE

To identify and quantitate alpha1-adrenergic receptor (alpha1AR) subtype expression in human detrusor.

MATERIALS AND METHODS

Initial studies to determine alpha1AR expression in human detrusor were performed using saturation binding with [125I]HEAT. Once the presence of alpha1ARs was documented, subtype (alpha1a, alpha1b, alpha1d) expression at the mRNA level (and comparison with rat) was determined with RNase protection assays (human detrusor) and RT-PCR (human detrusor, rat whole bladder). Competition binding analysis with the alpha1dAR-selective ligand BMY7378 was used to measure alpha1AR subtype expression at a protein level in human detrusor.

RESULTS

Alpha1AR expression in human detrusor was low but reproducible (6.3 +/- 1.0 fmol./mg. total protein). RNase protection assays performed on total RNA extracted from human detrusor revealed the following alpha1AR subtype expression: alpha1d (66%) > alpha1a (34%), and no alpha1b. RT-PCR confirmed alpha1AR subtype mRNA distribution in human detrusor with alpha1d (approximately 60-70%) > alpha1a (approximately 30-40%), and a lack of alpha1b mRNA. Rat whole bladder expressed different alpha1AR subtype mRNA than human detrusor, with alpha1a approximately alpha1b approximately alpha1d. The presence of alpha1d > alpha1a expression in human detrusor was confirmed at a protein level by competition analysis utilizing BMY7378 which revealed a two-site fit, with Ki and high affinity binding (66%) consistent with the alpha1dAR subtype.

CONCLUSIONS

Human detrusor contained two alpha1AR subtypes (alpha1d > alpha1a), a finding that is different from rat, another commonly used animal model. Since non-subtype selective alpha1AR antagonists ameliorate irritative bladder symptoms (in men and women with/without outlet obstruction), and Rec 15/2739 (alpha1a selective antagonist) does not improve symptom scores in BPH, our findings suggest bladder alpha1dARs may provide a potentially novel mechanism underlying these therapeutic benefits.

Alpha1-adrenergic receptor subtypes in human detrusor

PURPOSE

To identify and quantitate alpha1-adrenergic receptor (alpha1AR) subtype expression in human detrusor.

MATERIALS AND METHODS

Initial studies to determine alpha1AR expression in human detrusor were performed using saturation binding with [125I]HEAT. Once the presence of alpha1ARs was documented, subtype (alpha1a, alpha1b, alpha1d) expression at the mRNA level (and comparison with rat) was determined with RNase protection assays (human detrusor) and RT-PCR (human detrusor, rat whole bladder). Competition binding analysis with the alpha1dAR-selective ligand BMY7378 was used to measure alpha1AR subtype expression at a protein level in human detrusor.

RESULTS

Alpha1AR expression in human detrusor was low but reproducible (6.3 +/- 1.0 fmol./mg. total protein). RNase protection assays performed on total RNA extracted from human detrusor revealed the following alpha1AR subtype expression: alpha1d (66%) > alpha1a (34%), and no alpha1b. RT-PCR confirmed alpha1AR subtype mRNA distribution in human detrusor with alpha1d (approximately 60-70%) > alpha1a (approximately 30-40%), and a lack of alpha1b mRNA. Rat whole bladder expressed different alpha1AR subtype mRNA than human detrusor, with alpha1a approximately alpha1b approximately alpha1d. The presence of alpha1d > alpha1a expression in human detrusor was confirmed at a protein level by competition analysis utilizing BMY7378 which revealed a two-site fit, with Ki and high affinity binding (66%) consistent with the alpha1dAR subtype.

CONCLUSIONS

Human detrusor contained two alpha1AR subtypes (alpha1d > alpha1a), a finding that is different from rat, another commonly used animal model. Since non-subtype selective alpha1AR antagonists ameliorate irritative bladder symptoms (in men and women with/without outlet obstruction), and Rec 15/2739 (alpha1a selective antagonist) does not improve symptom scores in BPH, our findings suggest bladder alpha1dARs may provide a potentially novel mechanism underlying these therapeutic benefits.