Alpha-Blockade in the Treatment of Symptomatic Benign Prostatic Hyperplasia

Electronic medical records-based retrospective, longitudinal, observational study to understand the patient management of benign prostatic hyperplasia with alpha-blockers monotherapy in Indian population

Objective

The present retrospective study evaluates the effectiveness and tolerability of alpha-blockers as monotherapy in patients with benign prostatic hyperplasia associated with lower urinary tract symptoms (LUTS).

Materials and Methods

A total of 335 male patients >50 years were categorized into four groups (Alfuzosin: 166, Silodosin: 67, Tamsulosin: 70, Prazosin: 32). The efficacy evaluated as a change in International Prostate Symptom Score (IPSS), peak flow rate (Qmax), residual urine volume, and relief from LUTS, and tolerability of the various alpha-blockers was assessed across the study group.

Results

At baseline, most of the patients in alfuzosin (60%), silodosin (77%), and tamsulosin (90%) groups presented with severe IPSS (20-35), whereas patients in the prazosin group (69%) presented with a moderate score. At the end of the study, the mean IPSS gradually improved to moderate (41%, 62%, 66%, and 28%) and mild (59%, 38%, 28%, and 72%) in the alfuzosin, silodosin, tamsulosin, and prazosin groups, respectively (P = 0.004), with improvement in mean change in residual urine volume and complete relief from LUTS symptoms with no surgical or radiological interventions. Overall, 194 adverse events (AEs) were observed in 38.8% of patients. Of the total AEs, patients in the alfuzosin, silodosin, tamsulosin, and prazosin groups experienced 21%, 22%, 39%, and 18% of AEs, respectively.

Conclusion

The nonselective alpha-adrenergic receptor antagonist, alfuzosin, emerged as noninferior in effectiveness and superior in tolerability than other selective alpha-blockers, silodosin, tamsulosin, and prazosin.

Does this treatment work for me? The patient's role in assessing medical care

Randomised clinical trials are designed to determine whether a particular treatment is appropriate to make a significant difference to the health of a defined population and to aid its approval for use. For an accurate, cheap and simple assessment to see if a treatment benefits an individual person, all that is needed is a pen, paper, simple pocket calculator and daily recording of a few variables. It requires the ability to read and write and to understand addition and division. Factorial design of experiments is used to show the impact of several variables and their interaction on the person’s health status. An example of a 75-year-old man with an enlarged prostate is used here to illustrate this approach. This person was able to understand and reduce side effects, lower the costs of medication by 83% and improve measured health status by 28%. A multivariate model for this person was then created with about 450 person-days of data.

Anticholinergic drugs versus other medications for overactive bladder syndrome in adults

BACKGROUND

Overactive bladder syndrome is defined as "urgency with or without urge incontinence, usually with frequency and nocturia". It is a common condition with significant economic and quality of life implications. While the condition's pathophysiology remains to be fully elucidated, pharmacotherapy is the main treatment option. Despite uncertainty as to drug treatment of choice, anticholinergics are increasingly being used in primary and secondary care settings. This review compares anticholinergic drugs with other types or classes of drugs for treating overactive bladder syndromes.

OBJECTIVES

To compare anticholinergic drugs with other types or classes of drugs for treating overactive bladder symptoms.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 20 December 2006) and the reference lists of relevant articles. No language or other limits were imposed.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials comparing anticholinergic drugs with other drugs for the treatment of overactive bladder symptoms. At least one arm of the study used an anticholinergic drug and at least one other arm used a non-anticholinergic drug.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the identified studies for eligibility and methodological quality and independently extracted data from the included studies. Data analysis was performed using RevMan software (version 4.2.8).

MAIN RESULTS

Twelve trials were included in the review. There were seven crossover trials and five parallel group studies. For the comparisons between anticholinergic drugs with tricyclic antidepressants, alpha adrenergic agonists, afferent nerve inhibitors, and calcium channel blocker a single trial was identified for each. Nine trials compared flavoxate with anticholinergics. There was no evidence of a difference in cure rates between anticholinergics and flavoxate. Adverse effects were more frequent in anticholinergic groups versus flavoxate groups (RR 2.28 95% CI 1.45 to 3.56). There was no strong evidence to favour either anticholinergic drugs or the comparators.

AUTHORS' CONCLUSIONS

Many of the drugs considered in trials in this review are no longer used in clinical practice (and this includes the most commonly tested - flavoxate). There is inadequate evidence as to determine whether any of the available drugs are better or worse than anticholinergic medications. Larger randomised controlled trials in clinical settings are required to further establish the role of these medications in the management of overactive bladder syndrome.

Anticholinergic drugs versus other medications for overactive bladder syndrome in adults

BACKGROUND

Overactive bladder syndrome is defined as "urgency with or without urge incontinence, usually with frequency and nocturia". It is a common condition with significant economic and quality of life implications. While the condition's pathophysiology remains to be fully elucidated, pharmacotherapy is the main treatment option. Despite uncertainty as to drug treatment of choice, anticholinergics are increasingly being used in primary and secondary care settings. This review compares anticholinergic drugs with other types or classes of drugs for treating overactive bladder syndromes.

OBJECTIVES

To compare anticholinergic drugs with other types or classes of drugs for treating overactive bladder symptoms.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 20 December 2006) and the reference lists of relevant articles. No language or other limits were imposed.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials comparing anticholinergic drugs with other drugs for the treatment of overactive bladder symptoms. At least one arm of the study used an anticholinergic drug and at least one other arm used a non-anticholinergic drug.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the identified studies for eligibility and methodological quality and independently extracted data from the included studies. Data analysis was performed using RevMan software (version 4.2.8).

MAIN RESULTS

Thirteen trials were included in the review. There were eight crossover trials and five parallel group studies. For the comparisons between anticholinergic drugs with tricyclic antidepressants, alpha adrenergic agonists, afferent nerve inhibitors, and calcium channel blocker a single trial was identified for each. Ten trials compared flavoxate with anticholinergics. There was no evidence of a difference in cure rates between anticholinergics and flavoxate. Adverse effects were more frequent in anticholinergic groups versus flavoxate groups (RR 2.28 95% CI 1.45 to 3.56). There was no strong evidence to favour either anticholinergic drugs or the comparators.

AUTHORS' CONCLUSIONS

Many of the drugs considered in trials in this review are no longer used in clinical practice (and this includes the most commonly tested - flavoxate). There is inadequate no evidence as to whether any of the available is better or worse than anticholinergic medications. Larger randomised controlled trials in clinical settings are required to further establish the role of these other medications in the management of overactive bladder syndrome.

Efficacy and safety of tamsulosin hydrochloride compared to doxazosin in the treatment of Indonesian patients with lower urinary tract symptoms due to benign prostatic hyperplasia

AIM

The objective of the study was to compare the efficacy and safety of tamsulosin hydrochloride and doxazosin in patients with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH).

METHODS

The safety and efficacy of tamsulosin (0.2 mg) and doxazosin (2 mg) was determined after once daily administration for 6 weeks in an open-label, randomized, multicenter study of 101 men with BPH. The International Prostatic Symptom Score (IPSS), maximal urinary flow rates (Qmax), average urinary flow rates (Qave) and residual urine were determined at baseline and again at 6 weeks as efficacy parameters. The primary parameters used for safety evaluation were vital signs (blood pressure and heart rate) and adverse events. The number of patients with a clinically significant response to treatment with tamsulosin or doxazosin was determined and defined as those with >20% improvement from the baseline Qmax or >20% decrease in total IPSS.

RESULTS

The total IPSS decreased significantly in both the tamsulosin and doxazosin groups compared to baseline. There was a significant difference in the decrease in total IPSS between two groups. Qmax, Qave and residual urine significantly improved only in the tamsulosin group. There were no significant differences in systolic blood pressure, diastolic blood pressure or heart rate profile in the tamsulosin group; however, doxazosin resulted in a significant difference in systolic and diastolic blood pressure. Tamsulosin was well tolerated; only three patients (6%) in the tamsulosin group reported an adverse event (dizziness) while 11 patients (22%) in the doxazosin group reported an adverse event (dizziness), one of whom withdrew from the study.

CONCLUSIONS

Tamsulosin was shown to be more effective than doxazosin in the treatment of LUTS due to BPH.

The preparation of HEK293 α1A or HEK293 α1B cell membrane stationary phase and the chromatographic affinity study of ligands of α1 adrenoceptor

As a novel bioaffinity chromatographic technique, cell membrane chromatography (CMC) originated in 1996. The cell membrane stationary phase (CMSP) consists of porous silica coated with active cell membranes. By immersing silica into a suspension of cell membranes, the whole surface of silica was covered by the cell membranes. The present study repeatedly investigated the interaction between ligands and receptors by employing the system of CMC and especially evaluated the accuracy and feasibility of the CMC model in the study of subtype receptors. The cDNA encoding alpha1A or alpha1B adrenergic receptors (ARs) was transfected into human embryonic kidney 293 (HEK293) cell lines; cell lines stably overexpressing subtype receptors were obtained. HEK293 alpha1A or HEK293 alpha1B ARs CMSP were prepared by immobilizing relevant cell membranes on silica. In the described chromatography-based CMSP, the retention times of nine alpha1 adrenoceptor ligands and calculated capacity factors, as chromatographic parameters, were recorded carefully. These results showed a good correlation with the affinity of the same compounds for the corresponding cloned alpha1 adrenoceptor subtype. The rank order of capacity factors was consistent with the affinity rank order obtained from radioligand binding assays. The immobilized subtype-selective CMSP was stable and reproducible. The study demonstrates that the HEK293 alpha1A and HEK293 alpha1B CMSP can be utilized for initial screening of drug candidates.

Recent advances in the identification of a 1- and a 2-adrenoceptor subtypes: therapeutic implications

The cloning of multiple subtypes of both alpha1- and alpha2-adrenoceptors has renewed interest in the therapeutic application of agents interacting with these receptors. Effort has primarily been directed towards the design of uroselective alpha1-adrenoceptor antagonists for the treatment of benign prostatic hyperplasia (BPH). Evidence is accumulating for the involvement of a novel alpha1-adrenoceptor, designated as alpha1L-adrenoceptor, in alpha1-adrenoceptor-mediated smooth muscle contraction in prostatic and other urogenital tissues. While several antagonists showing a high degree of uroselectivity in animal models have been identified, their clinical superiority over the currently available alpha1-adrenoceptor antagonists has not yet been demonstrated. It is possible that the interaction with alpha1-adrenoceptors, as yet uncharacterised subtypes, at non-prostatic sites contributes to the therapeutic activity of this drug class in BPH. The alpha1-adrenoceptor subtypes involved in the control of vascular tone are currently being evaluated, and the profile of interaction with the various alpha1-adrenoceptor subtypes may play a key role in the efficacy of cardiovascular drugs such as carvedilol. Alpha2-adrenoceptor agonists are now being employed for a variety of therapeutic applications, most involving actions on receptors within the central nervous system (CNS). These agents are useful in the treatment of hypertension, glaucoma, opiate withdrawal and attention deficit hyperactivity disorder (ADHD), and as analgesics and adjuncts to general anaesthesia. While subtype selectivity has not yet been applied to the design of new alpha2-adrenoceptor agonists for these applications, recent gene mutation/knock-out experiments have identified the alpha2-subtypes involved in some of these actions, and optimisation of a therapeutic profile may be possible. Furthermore, the design of agents combining affinities for multiple adrenoceptor subtypes, or the combination of a specific adrenoceptor affinity profile with another pharmacological action, may offer advantages over molecules selective for an individual adrenoceptor subtype.

Comparative efficacy of two alpha-adrenoreceptor antagonists, doxazosin and alfuzosin, in patients with lower urinary tract symptoms from benign prostatic enlargement

OBJECTIVES

To compare doxazosin and alfuzosin in patients with moderate to severe lower urinary tract symptoms (LUTS) suggestive of bladder outlet obstruction.

PATIENTS AND METHODS

In all, 210 men with LUTS were randomized to receive doxazosin 1-8 mg once daily or alfuzosin 5-10 mg divided in two or three daily doses in a 14-week, multicentre, double-blind, baseline-controlled, dose-titration study. The International Prostate Symptom Score (IPSS) and maximum urinary flow rate were used to assess the efficacy of the treatment.

RESULTS

At study completion, the mean dose of doxazosin was 6.1 mg/day and alfuzosin 8.8 mg/day. The least squares mean (se) change from baseline in total IPSS was -9.23 (0.6) for doxazosin and -7.45 (0.6) (both P < 0.001) for alfuzosin. The respective mean change from baseline in irritative symptoms was -3.5 (0.2) and -2.8 (0.3) (both P < 0.001). The differences between the treatment groups were statistically significant in favour of doxazosin (total IPSS, P = 0.036; irritative symptoms, P = 0.049). The improvement between groups was also significantly different for postvoid residual urine volume, at -29.19 (8.6) and + 9.59 (8.9) mL for doxazosin and alfuzosin, respectively (P = 0.002). Improvements in mean and maximum urinary flow rates were similar for both treatments, at + 1.5 and + 1.2, and + 2.8 and + 2.5 mL/s, respectively. Doxazosin and alfuzosin were both well tolerated, with most all-cause adverse events reported as mild or moderate.

CONCLUSIONS

The mean doses of doxazosin and alfuzosin used in this study were not equipotent. Doxazosin 6.1 mg/day produced significantly greater improvements than alfuzosin 8.8 mg/day in total and irritative urinary symptom scores and postvoid residual urine volume in men with moderate to severe LUTS. Changes in maximum and mean flow rates were comparable. Doxazosin and alfuzosin were both well tolerated.

Urodynamic effects of alpha1-blocker tamsulosin on voiding dysfunction in patients with neurogenic bladder

BACKGROUND

The therapeutic role of alpha-blockers in the treatment of voiding disorders due to benign prostatic hyperplasia has been extensively examined. To investigate a possible effect of alpha1-blocker on urodynamic voiding parameters in patients with neurogenic bladder, we conducted a clinical trial using tamsulosin.

METHODS

Twenty-four patients (14 men and 10 women) ranging from 24 to 82 years of age (mean age 61 years) with neurogenic bladder were analyzed. Urodynamic studies were performed before and after treatment with 0.4 mg tamsulosin daily for 4 weeks.

RESULTS

On uroflowmetry, the average flow rate (from 4.6 +/- 3.3 to 6.7 +/- 3.0 mL/s, P = 0.04), maximum flow rate (from 9.4 +/- 6.8 to 14.1 +/- 7.0 mL/s, P = 0.016) and residual urine rate (from 46 +/- 29 to 32 +/- 21%, P = 0.02) improved significantly. In patients with detrusor contraction during voiding, detrusor opening pressure and detrusor pressure at maximum flow decreased significantly from 69.0 +/- 36.2 to 49.2 +/- 26.4 cmH2O (P = 0.046) and from 66.7 +/- 34.6 to 53.6 +/- 26.5 cmH2O (P = 0.007), respectively. On the other hand, in patients with detrusor areflexia, vesical opening pressure (from 78.2 +/- 23.4 to 61.6 +/- 25.2 cmH2O), or vesical pressure at maximum flow (from 68.6 +/- 23.2 to 62.9 +/- 25.2 cmH2O) did not change significantly after treatment.

CONCLUSION

Tamsulosin reduces functional urethral resistance during voiding and improves flow rate in patients with neurogenic bladder. It has more beneficial urodynamic effects in patients with detrusor contraction during voiding than in patients with detrusor areflexia.

Adenosine 5'-triphosphate (ATP) is an excitatory cotransmitter with noradrenaline to the smooth muscle of the rat prostate gland

1. This study investigated whether adenosine 5'-triphosphate (ATP) is involved in neurotransmission to the rat prostate gland. 2. Fluorescence immunohistochemistry carried out on formaldehyde-fixed and frozen sections of rat prostate showed immunoreactivity for the P2X(1)-receptor in the fibromuscular stroma surrounding the secretory acini but not in the glandular epithelium. P2X(2)-, P2X(3)-, P2X(4)- and P2X(7)-receptors were immunonegative in the rat prostate stroma. Double-staining procedures showed P2X(1)-receptor immunoreactivity to be colocalized with alpha-actin immunoreactivity. 3. Isolated organ bath studies investigated whether drugs, which modify purinergic mechanisms, are able to affect contractility of the rat prostate gland. Suramin (100 micro M) and alphabetamethylene ATP (10 micro M) inhibited contractile responses to trains of electrical-field stimulation (70 V, 0.5 ms, 0.1-2 Hz) in the absence and presence of prazosin (300 nM). Responses to 5-20 Hz were unaffected by suramin or alphabetamethylene ATP. 4. Exogenous application of ATP analogues to unstimulated isolated preparations of rat prostate produced concentration-dependent suramin (100 micro M) sensitive transient contractions with a relative order of potency: alphabetamethylene ATP>betagammamethylene ATP>ATP. 5. Adenosine and adenosine 5'-monophosphate (AMP) did not produce contractile responses. 6. These results suggest that P2X(1)-receptors for ATP, which mediate contractions are present in the fibromuscular stroma of the rat prostate. The relative order of potency of ATP analogues in producing contractions of the rat prostate is consistent with the activation of P2X(1)-receptors. Inhibition by suramin and alphabetamethylene ATP of electrically evoked nerve-mediated contractions of the rat prostate implies that ATP contributes to this contractile response and is therefore a cotransmitter with noradrenaline during low-frequency stimulation.

Long-term clinical and biologic effects of the lipidosterolic extract of Serenoa repens in patients with symptomatic benign prostatic hyperplasia

Permixon, the lipidosterolic extract of Serenoa repens, is widely used for the treatment of symptoms associated with benign prostatic hyperplasia (BPH). This open study assessed the efficacy and tolerability of Permixon 160 mg twice daily administered for 2 years. One hundred fifty-five men with clinically diagnosed BPH and complaints of prostatic symptoms were enrolled in the study. At 6, 12, 18, and 24 months, the International Prostate Symptom Score (I-PSS), quality of life, and sexual function score were recorded, and urodynamics and biologic values were measured. Adverse events were recorded every 3 months. I-PSS and quality of life improved significantly from baseline at each evaluation time point. At the end of the study and at each evaluation, maximum urinary flow also improved significantly. Prostate size decreased. Sexual function remained stable during the first year of treatment and significantly improved (P = .001) during the second year. Prostate-specific antigen was not affected, and no changes in plasma hormone levels were observed. Nine patients reported 10 adverse events, none related to treatment. Improvements in efficacy parameters began at 6 months and were maintained up to 24 months. These data demonstrate the long-term efficacy and tolerability of Permixon and support its use as a first-line medical therapy for uncomplicated symptomatic BPH.

The lipidosterolic extract of Serenoa repens in the treatment of benign prostatic hyperplasia: a comparison of two dosage regimens

This 6-month double-blind, randomized, parallel-group study compared two dose regimens of Libeprosta, the lipidosterolic extract of Serenoa repens in 100 male outpatients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH). The patients received two 80-mg tablets twice daily or two 80-mg tablets three times daily. Baseline evaluations included maximum and mean urinary flow rates, postvoid residual urine volume, and International Prostate Symptom Score (I-PSS) total and quality-of-life scores. Both regimens significantly reduced the I-PSS mean total score from baseline values (P<.001); improvements achieved statistical significance after month 3 and were maintained for the duration of the study. Significant improvements from baseline also occurred in quality-of-life scores, maximum and mean urinary flow rates, and residual urine volume (P<.05). The decrease in residual urine with both regimens was highly significant (P<.001). No significant differences in efficacy were noted between the two dose groups, and no treatment-related complications or clinical adverse events occurred. In this clinical study, the lipidosterolic extract of Serenoa repens was a well-tolerated agent that may significantly improve lower urinary tract symptoms and flow measurements in men with BPH.

Meta-analysis of randomized trials of terazosin in the treatment of benign prostatic hyperplasia

OBJECTIVES

To determine the effectiveness of the long-acting alpha(1)-adrenergic receptor blocking agent terazosin compared with placebo on lower urinary tract symptoms and peak urinary flow rate in men with clinical benign prostatic hyperplasia.

METHODS

A formal meta-analysis of all nine randomized trials of terazosin using both an Empirical Bayes and a fully Bayesian approach was conducted. A pooled analysis was conducted on those studies in which patients had a baseline assessment of prostate volume by transrectal ultrasonography.

RESULTS

No evidence of heterogeneity was found in the estimated effects of terazosin on the change in peak flow rates in the studies. Terazosin treatment was associated with an increase in the peak flow rate of 1.4 mL/s (95% confidence interval [1.0, 1.7]) compared with placebo. Terazosin resulted in an average reduction of 2.2 points over placebo (95% confidence interval [1.6, 3.0]) regarding the common symptom score (range 0 to 36 points). A mild heterogeneity was found across the studies, with the decrease in symptom score slightly greater with longer treatment duration. No evidence was found that the baseline prostate volume influenced the effect of terazosin.

CONCLUSIONS

Terazosin was effective and superior to placebo in reducing symptoms and increasing the peak urinary flow rate. The effect of terazosin on the peak urinary flow rate was apparent in studies as short as 8 weeks. Most importantly, the effect of terazosin on symptoms and peak urinary flow rate was independent of the baseline prostate size for the range of prostate volumes reported.

Discontinuation of alpha-blockade after initial treatment with finasteride and doxazosin in men with lower urinary tract symptoms and clinical evidence of benign prostatic hyperplasia

OBJECTIVES

To determine the effect of discontinuation of alpha-blockade and continuation of finasteride in men with lower urinary tract symptoms and enlarged prostates receiving combination treatment and to determine whether the alpha-blocker dose influences the ability to discontinue it.

METHODS

We treated 272 consecutive men with a prostate size greater than 40 g and American Urological Association symptom score greater than 20 with 5 mg finasteride and 2 mg doxazosin daily. Two hundred forty men reported a favorable response to therapy, defined as any reduction in symptom score and toleration of the medications. The dose was maintained at 2 mg doxazosin in 100 men and was titrated to 4 mg doxazosin in 80 patients and to 8 mg doxazosin in an additional 60 patients. We discontinued doxazosin at 3, 6, 9, or 12 months, while continuing finasteride, and then re-evaluated the patients 1 month later to determine whether any worsening of symptoms had resulted.

RESULTS

In patients discontinuing doxazosin at 3 months, success (defined as no increase in symptom score and no desire to resume doxazosin) was reported by 20%, 15%, and 13% of those taking 2, 4, and 8 mg, respectively. In patients discontinuing doxazosin at 6 months, success was reported by 48%, 45%, and 40% of those taking 2, 4, and 8 mg, respectively. In patients discontinuing doxazosin at 9 months, success was reported by 84%, 80%, and 73% of those taking 2, 4, and 8 mg, respectively. In patients discontinuing doxazosin at 12 months, success was reported by 84%, 85%, and 87% of those taking 2, 4, and 8 mg, respectively.

CONCLUSIONS

Patients with lower urinary tract symptoms and moderately enlarged prostates initially receiving combination therapy using finasteride and an alpha-blocker are likely to experience no significant symptom deterioration after discontinuing the alpha-blocker after 9 to 12 months of combination therapy regardless of the dose of alpha-blocker chosen.

Cyclic imides as potent and selective alpha-1A adrenergic receptor antagonists

We disclose a new compound class of potent and selective alpha-1A adrenergic receptor antagonists exemplified by the geminally, disubstituted cyclic imide 7. The optimization of lead compounds resulting in the cyclic imide motif is highlighted. The results of in vitro and in vivo studies of selected compounds are presented.

The short-term effects of terazosin in Japanese men with benign prostatic hyperplasia

We evaluated the short-term efficacy of terazosin for treating symptomatic benign prostatic hyperplasia (BPH). Thirty men, aged 52 to 83 years (mean: 69.2 years) complaining of obstructive urinary symptoms due to BPH who had not received any prior treatment for their symptoms were orally administered 2 mg/day of terazosin. Symptoms (the total IPSS and the obstructive and irritative symptom scores) and objective parameters (peak flow rate [Qmax] and prostatic volume) were evaluated before treatment and after 1, 2, and 4 weeks of treatment. The mean total IPSS and the mean symptom scores for weak stream and nocturia were significantly decreased after only 1 week of treatment, while the mean scores for emptying, frequency, and urgency were significantly decreased after 2 weeks of treatment. However, the mean scores for intermittency and hesitancy did not decrease significantly at any time during treatment. Regarding objective parameters, the mean Qmax was significantly improved after 1 week of treatment, but the mean prostatic volume remained almost unchanged after 4 weeks. In conclusion, short-term terazosin therapy not only improved Qmax but also alleviated symptoms including irritative symptoms.

Induction of apoptosis and inhibition of cell proliferation by the lipido-sterolic extract of Serenoa repens (LSESr, Permixon in benign prostatic hyperplasia

BACKGROUND

To determine the mechanism by which prostate volume increases during the development of BPH and to evaluate the effect of LSESr (Permixon), a phytotherapeutic agent, we investigated apoptosis and cell proliferation in the stroma and epithelium of normal prostate and of BPH tissues from patients treated with or without LSESr.

METHODS

MIB-1 staining and the in situ end-labeling assay were used to evaluate the proliferative-apoptotic balance in normal prostates and in BPH tissues. Quantitative assessment was performed using an image analysis system.

RESULTS

In normal prostates, there was no significant difference between apoptotic and proliferative indices. Cell numbers and proliferative indices were higher in BPH than in normal prostates, while apoptosis values were similar. In the BPH treated group, LSESr significantly inhibited proliferation and induced cell death in both epithelium and stroma.

CONCLUSIONS

Induction of apoptosis and inhibition of cell proliferation are likely to be the basis for the clinical efficacy of LSESr.

Species differences in the actions of sensory neuropeptides on contractility of the smooth muscle of the rat and guinea-pig prostate

1. The present review describes the actions of sensory neuropeptides on the contractility of the rat and guinea-pig prostate gland and discusses the differences in sensitivity of the smooth muscle of the prostates taken from these species to these neuropeptides. 2. Nerve fibres immunoreactive for the tachykinins substance P and neurokinin A, as well as for the sensory neuropeptide calcitonin gene-related peptide (CGRP), are sparsely distributed throughout the fibromuscular stroma of the prostate gland in both the rat and guinea-pig. 3. In functional experiments, tachykinin agonists potentiate electrical field stimulation-induced contractile responses of prostates taken from guinea-pigs, but have no effect on those taken from rats. This potentiation is through stimulation of tachykinin NK1-receptors. 4. Conversely, CGRP inhibits electrical field stimulation-induced contractile responses of prostates taken from rats, but has no effect on those taken from guinea-pigs. 5. It is concluded that although the sensory innervation to the prostate glands of the rat and guinea-pig appears similar, the nature and sensitivity of the contractile response of the prostatic smooth muscle to applied sensory neuropeptides is vastly different in the two species.

The clinical role of alpha-blockers in the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a highly prevalent condition that represents a significant health problem, which is likely to worsen as the population continues to age. alpha-1 adrenoceptor antagonists have been used in the treatment of this condition for well over 20 years and much is now known about their effects on the urinary tract. As these drugs have improved, their use as a first line treatment option in patients with lower urinary tract symptoms (LUTS), secondary to BPH, has continued to increase. This review details some of the background and rationale for the use of these drugs and, using the available information, compares their efficacy and tolerability profiles.

The autonomic and sensory innervation of the smooth muscle of the prostate gland: a review of pharmacological and histological studies

1. We review literature demonstrating (a) the presence and (b) the actions of substances that mediate or modify neuroeffector transmission to the smooth muscle of the prostrate stroma of a number of species including man. 2. In all species studied prostatic stroma, but not secretory acini, receives rich noradrenergic innervation. Stimulation of these nerves causes contractions of prostate smooth muscle that are inhibited by guanethidine and by alpha1-adrenoceptor antagonists that probably act at the alpha1L-adrenoceptor. Such actions underlie the clinical use of alpha1-adrenoceptor antagonists in benign prostatic hyperplasia (BPH). 3. Acetylcholinesterase-positive nerves innervate prostatic stroma as well as epithelium. Atropine reduces nerve-mediated contractions of stromal muscle in the rat, guinea-pig and rabbit. M1, M2 and M3 muscarinic receptors have been implicated in eliciting or facilitating contraction in the prostate from guinea-pig, dog and rat, respectively. 4. Adenine nucleotides and nucleosides, nitric oxide (NO), opioids, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) may act as co-transmitters or modulators in autonomic effector nerves supplying prostate stroma. Adenosine inhibits neurotransmission to the rat prostate, and NO is inhibitory in prostate from human, rat, rabbit, pig and dog. The activity of peptides present in the relatively sparse sensory innervation of the prostate exhibits species variation, but, when effective, calcitonin gene-related peptide is inhibitory while tachykinins are stimulant. The roles of NPY and VIP in modulating stromal contractility remain unclear. 5. Taken together the current literature indicates that, in addition to noradrenaline, other neurotransmitters and neuromodulators may regulate the tone of prostatic smooth muscle. Whether drugs that mimic or modify their actions might be useful in providing symptomatic relief of the urinary symptoms associated with BPH remains to be established.

Calcitonin gene-related peptide (CGRP) inhibits contractions of the prostatic stroma of the rat but not the guinea-pig

This study investigated the presence and effects of calcitonin gene-related peptide (CGRP) within the rat and guinea-pig prostate glands. Immunohistochemical studies demonstrated that CGRP immunoreactive nerve fibres are sparsely distributed throughout the prostatic fibromuscular stroma in both species. These CGRP immunopositive nerve fibres shared a similar distribution profile but were not colocalized with tyrosine hydroxylase immunopositive nerve fibres which also innervate the prostatic stroma of these species. Nerve terminals within rat and guinea-pig prostatic tissues were electrically field stimulated (60 V, 0.5 ms, 10 Hz, 20 pulses every 60 s). In guinea-pig preparations, application of human alpha-CGRP, rat adrenomedullin or rat amylin (0.1 nM-1 microM) had no effect on responses to field stimulation. In contrast, both rat and human alpha-CGRP (10 pM-300 nM), rat adrenomedullin (0.3 nM-1 microM) and rat amylin (3 nM-1 microM) concentration-dependently inhibited electrically evoked contractile responses in the rat prostate. The relative order of potency was rat alpha-CGRP=human alpha-CGRP>rat adrenomedullin>rat amylin. The inhibition by rat alpha-CGRP of field stimulation-induced contractions in the rat prostate was competitively antagonized by human CGRP((8-37)) (1, 3 and 10 microM) with a pA(2) of 6.20+/-0.13. Rat alpha-CGRP (10 nM) attenuated contractile responses of the rat prostate to exogenously added noradrenaline (1-100 microM). Inhibitory concentration-response curves to rat alpha-CGRP in rat prostates were unaffected by preincubation in either glibenclamide (10-100 microM), N-nitro-L-arginine methyl ester (L-NAME) (10 microM), bestatin (10 microM), captopril (10 microM) or phosphoramidon (3 microM). Our results indicate that CGRP-induced inhibition of electrically evoked contractions in the rat prostate occurs through activation of postjunctional CGRP(2) receptors which act independently of a K(ATP) channel or nitrergic mechanisms. Degradation of rat alpha-CGRP via peptidases does not appear to occur in the rat prostate.

Effects of spinal alpha 1-adrenoceptor antagonism on bladder activity induced by apomorphine in conscious rats with and without bladder outlet obstruction

To test the hypothesis that the spinal control of micturition involves alpha 1-adrenoceptors, the urodynamic effects of intrathecal and intraarterial alpha 1-adrenoceptor blockade on apomorphine-induced bladder activity in rats were studied. Continuous cystometry was performed in conscious female Sprague-Dawley rats with and without bladder outflow obstruction. In normal rats, subcutaneous apomorphine, 30 micrograms/kg, induced bladder activity that was abolished or attenuated by the alpha 1-adrenoceptor antagonists indoramin and doxazosin given intrathecally or intra-arterially. In rats with outlet obstruction, apomorphine 30 micrograms/kg caused no change in cystometric parameters. However, at a dose of 100 micrograms/kg the drug induced bladder activity, which was attenuated by intrathecal indoramin or doxazosin. These results suggest that the bladder activity evoked by apomorphine-stimulation of bulbospinal pathways can be influenced by alpha 1-adrenoceptors at the spinal and peripheral levels, both in normal rats and in rats with bladder hypertrophy secondary to outlet obstruction.

[Program for the substitution of therapeutic equivalents in the hospital setting]

BACKGROUND

A Program of Therapeutic Equivalents (TEP) is here reported which was elaborated and is currently in force at a third level university teaching hospital.

MATERIALS AND METHODS

Therapeutic equivalents were selected within the same pharmacologic group on the basis of approved indications and both efficiency and safety data.

RESULTS

TEP considers: a) the substitution of drugs which are considered therapeutic equivalents; b) withdrawal of drugs which have not proved efficiency or are of no interest for inpatients; c) continuation of therapies when changes are not advisable, and d) indistinct use of homologous drugs. From August 1998 up to April 1999, TEP was applied in 505 occasions; it was accepted in 499 (99%) and rejected in 6 (1%).

DISCUSSIONS

The substitution of therapeutic equivalents should be viewed in the context of selecting the most appropriate drugs to be used in the hospital setting. TEP should be a consensus document and supervised by the Pharmacy and Therapeutics Commission.

Adrenoceptor subclassification: an approach to improved cardiovascular therapeutics

The subdivision of alpha adrenoceptors into the alpha 1 and alpha 2 classes was the impetus for the design of the selective alpha 1-adrenoceptor antagonists, which remain useful antihypertensives. alpha 2-Adrenoceptor agonists also have application as antihypertensive drugs, based on their ability to reduce sympathetic outflow. Likewise, subdivision of the beta adrenoceptors has lead to the development of selective beta 1-adrenoceptor antagonists as antihypertensive and selective beta 2 agonists as bronchodilators. In the past decade, both the alpha 1 and alpha 2 adrenoceptors have been further subdivided, each into three subclasses. In addition, there is strong functional evidence to suggest the presence of additional adrenoceptor subtypes, such as the "alpha 1L" adrenoceptor and "beta 4" adrenoceptor. alpha 1A (or alpha 1L)-Adrenoceptor antagonists have been evaluated for benign prostatic hyperplasia (BPH), and selective alpha 1A agonists for stress incontinence. Gene knockout experiments in mice suggest an important role for the alpha 1B adrenoceptor in the control of vascular tone. Hence, selective alpha 1B antagonists may offer a new approach toward hypertension. Although targeting of specific adrenoceptors can be used to optimize the therapeutic profile of a drug, there are also cases where blockade of multiple adrenoceptors is desirable, as with the alpha/beta-adrenoceptor antagonist carvedilol in congestive heart failure. It is possible that combination of affinities for selected adrenoceptor subtypes within a single molecule may be desirable for certain applications.

Tamsulosin for the treatment of benign prostatic hypertrophy

OBJECTIVE

To review the information necessary to assess the efficacy and safety of tamsulosin compared with other adrenergic antagonists for treatment of symptomatic benign prostatic hyperplasia.

DATA SOURCES

A search was conducted of Cumulated Index Medicus, January 1993-August 1999, which was restricted to human trials and English-language journals.

STUDY SELECTION AND DATA EXTRACTION

Efficacy studies were included if the design was randomized and included a control group. Drug safety was assessed using data from any patient series or controlled study.

DATA SYNTHESIS

Tamsulosin, a uroselective alpha1A-adrenergic receptor antagonist, relaxes smooth muscle in the prostate and bladder neck, thereby enhancing bladder emptying. In randomized, controlled clinical trials using standardized instruments, tamsulosin improves obstructive voiding symptoms by at least 25% in 65-80% of patients with symptomatic benign prostatic hyperplasia. Tamsulosin also improves peak urinary flow rate by 1.4-3.6 mL/sec in various studies and reduces post-void residual urine volume. The usual dosage of tamsulosin was 0.4 or 0.8 mg orally once a day in the studies performed in the US and Europe; daily doses of 0.1-0.4 mg were used in studies performed in Japan. The beneficial effects of tamsulosin on voiding symptoms, peak urinary flow rate, and bladder emptying appear to be dose-related, up to a ceiling dose of 0.4 mg. The most common adverse effects are headache, asthenia, dizziness, and rhinitis-like complaints. Retrograde or delayed ejaculation occurs in 4.5-14.0% of patients and has required discontinuation of treatment in a minority of these patients. At the usual dose of 0.4-0.8 mg/d, tamsulosin does not appear to significantly reduce blood pressure, increase heart rate, or cause first-dose syncope; therefore, dosage titration is not necessary when initiating treatment. Use of nifedipine, enalapril, atenolol, furosemide, or digoxin does not require dosage modification when tamsulosin is initiated concomitantly; hypotension has not been reported with combined use of tamsulosin and these commonly used agents.

CONCLUSIONS

Tamsulosin is an improvement over other alpha-adrenergic antagonists for the management of symptoms of benign prostatic hyperplasia. It is a more convenient alternative that does not require initial dosage titration, has a fast onset of action, and has a low potential to cause hypotension when used alone or in combination with commonly used antihypertensive agents. It is more costly than some of the other second-generation alpha-adrenergic antagonists.

alpha(1L)-adrenoceptors mediate noradrenaline-induced contractions of the guinea-pig prostate stroma

The alpha(1)-adrenoceptor subtype mediating noradrenaline-induced contractions of the guinea-pig isolated prostatic smooth muscle was investigated. Noradrenaline produced concentration-dependent contractions of the tissue with a mean pD(2) value of 5.26+/-0.03 (n=20). These contractions were antagonised by prazosin, 2-(2, 6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride (WB-4101), N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha, alpha-dimethyl-1H-indole-3-ethanamine hydrochloride (RS-17053) and (R)-5-[2-[[2-(2-ethoxyphenoxy)ethyl]amino]-2-methylethyl]-2- methoxybenzensulfonamide methanesulphonate hydrate (tamsulosin). Mean pA(2) or apparent pK(B) estimates for the antagonism of noradrenaline were 8.15+/-0.05 for prazosin; 8.83+/-0.11 for WB-4101, 7.18+/-0.14 for RS-17053 and 10.11+/-0.12 for tamsulosin. The relatively low estimates of the apparent dissociation constant for all antagonists except tamsulosin indicate that an alpha(1L)-adrenoceptor mediates noradrenaline-induced prostatic smooth muscle contraction in the guinea-pig prostate gland.

Prediction of alpha-blocker response in men with benign prostatic hyperplasia by magnetic resonance imaging

OBJECTIVES

To assess the value of magnetic resonance imaging (MRI) for predicting the alpha-blocker response in men with symptomatic benign prostatic hyperplasia (BPH) and to examine the relationship between MRI and the area density of smooth muscle cells in BPH.

METHODS

Twenty-eight men were consecutively enrolled in this study and received tamsulosin 0.2 mg once daily for 4 to 6 weeks. The efficacy of tamsulosin was determined by measuring improvements in the maximum urinary flow rate (Qmax) and International Prostate Symptom Score (IPSS). The patients underwent T2-weighted MRI and were separated into a high (H) or iso-low (IL) group according to the signal intensity of the inner gland of the prostate compared with that of bone marrow of the proximal femur head. The area density of smooth muscle cells was determined using immunostaining with antiactin antibody in 16 prostate specimens.

RESULTS

IPSS significantly decreased after the administration of tamsulosin from 16 +/- 1 to 8 +/- 1 (n = 28, P <0.0001 ), and 76.7% of the patients had an improved IPSS of 25% or greater. Qmax was significantly increased in group IL (P = 0.03) but not in group H. Of the patients in group IL, 53.3% had a Qmax response (an increase of Qmax of 30% or more); 15.4% did so in group H (P = 0.04). The area density of smooth muscle cells was 48.1 +/- 3.7% in group IL (n = 9) and 36.7 +/- 3.2% in group H (n = 7, P = 0.04).

CONCLUSIONS

MRI is useful in estimating the area density of smooth muscle cells in the prostate and in predicting Qmax response for alpha-blocker therapy in patients with symptomatic BPH.

A multicenter, community-based study of doxazosin in the treatment of concomitant hypertension and symptomatic benign prostatic hyperplasia: the Hypertension and BPH Intervention Trial (HABIT)

As men age, the incidence of both benign prostatic hyperplasia (BPH) and hypertension increases. Concomitant occurrence of these conditions also increases with age, and the 2 are frequently encountered together in primary care practice. In addition, many patients with hypertension require >1 antihypertensive agent to adequately control blood pressure. In a multicenter, community-based, 8-week, uncontrolled, open-label study, we evaluated doxazosin, a selective alpha1-adrenergic-receptor antagonist, in 491 patients with concomitant symptomatic BPH (American Urological Association [AUA] symptom score > or =12) and hypertension, some previously untreated and some with inadequately controlled hypertension (systolic blood pressure 120-179 mm Hg or diastolic blood pressure [DBP] 80-109 mm Hg) despite taking 1 or 2 antihypertensive agents. Patients were allocated to 1 of 4 groups at baseline according to their diastolic blood pressure (control was considered DBP <90 mm Hg) and whether they had received antihypertensive medication before the study. Thus the 4 groups were treated/well-controlled, treated/poorly controlled, untreated/hypertensive, and untreated/normotensive. In all patient groups, doxazosin therapy significantly improved AUA total symptom and bothersomeness scores and BPH-specific indices of health status and interference with activities (P<0.001). Significant improvements in BPH symptoms were observed with doxazosin, regardless of whether initial symptoms were moderate or severe (P<0.001). Clinically important blood pressure lowering occurred only in the patient groups in which blood pressure had been elevated at baseline. Patients whose blood pressure was poorly controlled at baseline, either without or with treatment (predominantly with angiotensin-converting enzyme inhibitors or calcium channel blockers), achieved adequate blood pressure control (reduction to <140/90 mm Hg) with the addition of doxazosin. Similar improvements in blood pressure and BPH symptoms were seen in both older (> or =65 years) and younger (45 to 64 years) patients, and doxazosin was well tolerated by both groups. The most frequent treatment-related adverse event was dizziness (13.0% of patients); however, patients classified the dizziness as mild in approximately 75% of reports, and severe dizziness was reported by only 2 patients (0.4%). Doxazosin is an effective antihypertensive agent when used in combination with agents from other antihypertensive classes in patients with poorly controlled hypertension and BPH, and is also successful as monotherapy for controlling both BPH and hypertension in patients with mild to moderate hypertension.

Comparison of once and twice daily dosage forms of Pygeum africanum extract in patients with benign prostatic hyperplasia: a randomized, double-blind study, with long-term open label extension

OBJECTIVES

To compare the efficacy and safety of Pygeum africanum extract, 50 mg twice daily and 100 mg once daily.

METHODS

Patients with symptomatic benign prostatic hyperplasia (BPH) entered a 2-month randomized, parallel-group, double-blind, comparative phase (group A, 50 mg twice daily; group B, 100 mg once daily), followed by a 10-month, open phase (100 mg once daily). Main efficacy assessment parameters included International Prostate Symptom Score (IPSS), quality of life (QOL), and maximum urinary flow rate (Qmax).

RESULTS

Two hundred nine patients completed the comparative phase in compliance with the protocol; 174 were included in the open phase. Both treatments had similar efficacy. IPSS (baseline 17 in both groups) improved by 38% in group A and 35% in group B. QOL improved by 28% in both groups. Qmax increased by 1.63 mL/s (16%) in group A and 2.02 mL/s (19%) in group B. After 12 months, the IPSS fell from 16 (baseline) to 9 (-46%). Half of the patients had an IPSS below 8. Mean Qmax increased by 1.65 mUs (15%). The safety profile was similar between groups and study phases.

CONCLUSIONS

P. africanum extract at 50 mg twice daily and 100 mg once daily proved equally effective and safe at 2 months. Further improvements in efficacy with a satisfactory safety profile were documented after 12 months.

Effects of alpha1-adrenoceptor antagonists on agonist and tilt-induced changes in blood pressure: relationships to uroselectivity

We evaluated the uroselectivity of a series of alpha1-adrenoceptor antagonists by comparing their potency against phenylephrine-induced increases in urethral perfusion pressure and diastolic blood pressure in the anesthetized rabbit and pithed rat. In the rabbit, Rec 15/2739 (N-[3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl]-3-methyl-4-oxo-2-phenyl -4H-1-benzopyran-8-carboxamide) as well as analogs with a chlorine substituent on the methoxyphenyl ring (Rec 15/2869) or this substituent combined with the replacement of the phenyl substituent on the pyran ring by cyclohexyl (Rec 15/3011) were 2-6-fold more potent against the urethral vs. vascular response to phenylephrine. Rec 15/2841 (N-[3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl]-3-methyl-4-oxo-2-cyc lohexy-4H-1-benzopyran-8-carboxamide) was only 1.5-fold more potent against the urethral response. SL 89.0591 and tamsulosin also showed selectivity for the urethral response (2-2.5-fold), while the quinazolines produced equipotent blockade of urethral and vascular responses (selectivity ratio = 0.9-1.1). The urethral selectivities of Rec 15/2739 and its derivatives were confirmed by evaluation of the response to tilt in sedated, hypovolemic rabbits. Phenylephrine challenge assays did not show any of the antagonists, with the exception of terazosin at 300 microg kg(-1), to be uroselective in the rat (selectivity ratios = 0.2-1.5); potentiation of tilt-induced hypotension in the anesthetized rat showed substantial differences from the rabbit, with Rec 15/2739, but not Rec 15/3011 and Rec 15/2841 showing orthostatic effects equivalent to that observed for prazosin. Hence, Rec 15/2739 was uroselective in the rabbit, but not in the rat, while two of its close structural analogs were highly uroselective in both species. An assay for orthostatic activity in the conscious rat yielded different results, showing prazosin and terazosin, but not Rec 15/2739, to cause a reversal of the pressor response to tilt. Hence, the apparent uroselectivity of an alpha1-adrenoceptor antagonist is both species- and assay-dependent.

A pilot study for a randomized controlled trial comparing the efficacy, safety and cost-effectiveness of surgical treatments of the prostate

OBJECTIVE

To assess the numbers of men in outpatients and subsequently undergoing transurethral resection of the prostate (TURP) who were referred during 1993-94 and 1996-97, thereby assessing the feasibility of a subsequent study of treatment efficacy in men with bladder outlet obstruction secondary to benign prostatic hyperplasia, prospectively randomized to the surgical treatment options, i.e. TURP, laser ablation of the prostate, transurethral needle ablation and T3 thermotherapy, to investigate treatment outcome, cost-efficacy and cost-benefit.

PATIENTS AND METHODS

All patients considered and consenting for prostate surgery were reviewed prospectively with a view to inclusion in the proposed trial. The diagnosis was based on two estimates of flow rate from voids of >150 mL and from symptoms assessed using the International Prostate Symptom Score. All patients had TURP explained by a urological surgeon and nursing staff, and subsequently had further consultation with research staff.

RESULTS

Patients seen in clinic as new referrals increased by 11% between the periods assessed, although the numbers undergoing TURP decreased by 19%. Of the 383 patients screened, who were on the waiting list for TURP, only 13 elected to enter the trial. Of the 383 men, 267 (67%) ultimately had prostate surgery, with 39 (10%) electing to continue with watchful waiting and 34 (9%) continuing with pharmacotherapy.

CONCLUSION

Although more men with benign prostatic disease and lower urinary tract symptoms are being seen in clinics, the reduced proportion of patients continuing to surgical intervention will lead to increasing difficulty in carrying out randomized controlled clinical trials assessing surgical options. With ever more therapeutic options available, patients find it difficult to make decisions in both the clinical situation and when asked to enter a trial. Fully informed decisions by both the surgeon and the patient will only be possible when objective data are available from trials that investigate outcome, cost-efficacy and cost-benefit. This study suggests that when presented with more information and counselling, fewer men decide to undergo prostate surgery for symptomatic BPH.

Differential vascular alpha1-adrenoceptor antagonism by tamsulosin and terazosin

AIMS

In patients with lower urinary tract symptoms suggestive of benign prostatic obstruction the alpha1-adrenoceptor antagonist terazosin lowers blood pressure whereas only very small if any alterations were reported with the alpha1-adrenoceptor antagonist tamsulosin. Therefore, we have compared the vascular alpha1-adrenoceptor antagonism of tamsulosin and terazosin directly.

METHODS

Ten healthy subjects were investigated in a randomized, single-blind, three-way cross-over design and received a single dose of 0.4 mg tamsulosin, 5 mg terazosin or placebo on 3 study days at least 1 week apart. Before and 1, 3, 5, 7, 10 and 23.5 h after drug intake, alterations of diastolic blood pressure and other haemodynamic parameters in response to a graded infusion of the alpha1-adrenoceptor agonist phenylephrine were determined non-invasively.

RESULTS

At most time points tamsulosin inhibited phenylephrine-induced diastolic blood pressure elevations significantly less than terazosin (5 h time point: median difference in inhibition 35%, 95% CI: 18.7-50.3%). On the other hand, phenylephrine-induced changes of cardiac output, heart rate and stroke volume were similar during both active treatments.

CONCLUSIONS

In doses equi-effective for treatment of lower urinary tract symptoms tamsulosin causes less inhibition of vasoconstriction than terazosin.

Tamsulosin treatment of 19,365 patients with lower urinary tract symptoms: does co-morbidity alter tolerability?

PURPOSE

We compare the tolerability and blood pressure effects of 0.4 mg. tamsulosin once daily in patients with lower urinary symptoms suggestive of benign prostatic obstruction with or without concomitant disease and/or antihypertensive medication.

MATERIALS AND METHODS

Data from 2 open label, observational studies (study 1, 9,507 patients treated for 4 weeks and study 2, 9,858 patients treated for 12 weeks) were analyzed for global tolerability and effects on blood pressure stratifying for co-morbidity (none, diabetes, hypertension, other cardiovascular disease) and co-medication (diuretics, beta-blockers, calcium channel blockers, angiotensin converting enzyme inhibitors).

RESULTS

Overall 90 and 95% of patients in studies 1 and 2, respectively, reported good or very good tolerability. While global tolerability was slightly reduced in patients with concomitant disease or some forms of medication (p < 0.05), it was rated as good or very good by more than 90 and 95% of patients even in those groups. In control patients, that is those with neither co-morbidity nor co-medication, the tamsulosin induced blood pressure reductions were similar to those previously reported for placebo treatment but were statistically significant (p < 0.05). Mean additional blood pressure reductions in patients with concomitant disease or medication were not more than 2 mm. Hg.

CONCLUSIONS

Tamsulosin is well tolerated and has marginal effects on blood pressure in the majority of patients. It largely maintains its good global tolerability and minimal blood pressure effects in patients with cardiovascular co-morbidity or diabetes, or those on co-medication with antihypertensive agents.

Neurohormonal stimulation of histamine release from neuroendocrine cells of the human adenomatous prostate

BACKGROUND

Neuroendocrine cells (NE) constitute a population of highly specialized cells in prostatic glands; histamine has never been described in these cells. This article shows the presence and the regulation of release of histamine in NE.

METHODS

In 21 prostatic adenomas, NE were identified by specific antisera against neuroendocrine markers (chromogranin-A, synaptophysin), histamine, and histidine decarboxylase (HDC); a rate HDC-cDNA probe was used to detect this enzyme by in situ hybridization.

RESULTS

Immunoreactive cells for chromogranin-A, histamine, and HDC were found among luminal epithelial glandular cells. Similar cells were also labeled with the HDC-cDNA probe. Glandular cells, isolated from prostatic adenomas, were shown to contain histamine (7-40 pmol/mg cellular protein). L(-) norepinephrine causes a time-dependent (t1/2 = 22 min) histamine release; the alpha 1-receptor antagonists WB-4101 and YM-617 specifically inhibited this release, in agreement with a mediation by alpha 1-adrenoreceptor subtype.

CONCLUSIONS

There is some evidence for the presence in prostatic adenomas of histamine-forming cells of neuroendocrine type; histamine release from these cells is under the control of alpha 1-adrenoreceptor subtype.

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

OBJECTIVES

To determine if men with normal peak urinary flow rates (PFR) and prostatism respond to terazosin.

METHODS

Forty-one men over the age of 50 years with an American Urological Association (AUA) symptom score greater than 8, postvoid residual urine volume (PVR) less than 300 mL, and no clinical or biochemical evidence of prostate cancer were treated with terazosin independent of the baseline PFR. The effect of terazosin on the AUA symptom score and PFR were compared for subjects with a PFR of 15 mL/s or less (group I) and those with a PFR greater than 15 mL/s (group II).

RESULTS

The baseline age, AUA symptom score, prostate volume, and PVR were not significantly different between the two groups. The mean changes in AUA symptom score were -45.0% and -49.5% for groups I and II, respectively. The mean changes in PFR were 7.0% and -26.6% for groups I and II, respectively.

CONCLUSIONS

The effect of terazosin on AUA symptom score is independent of baseline PFR, indicating that the mechanism of action of terazosin is not exclusively mediated by reduction of bladder outlet obstruction. Randomized controlled studies are required to confirm this provocative observation.

Prostatic alpha 1-adrenoceptors and uroselectivity

BACKGROUND

alpha 1-adrenoceptor antagonists (blockers) are now commonly used in the treatment of the symptoms of lower urinary tract obstruction. Originally phenoxybenzamine, a non-selective antagonist at both alpha 1- and alpha 2-adrenoceptors, was used by Marco Caine. In an attempt to minimize side effects, selective alpha 1-antagonists, e.g. prazosin, were subsequently developed. More recently, agents such as alfuzosin, doxazosin, terazosin, and tamsulosin have been introduced and claims of "uroselectivity" and "prostate" selectivity have emerged.

METHODS

This review attempts to put these claims into perspective and represents a comprehensive analysis of all pre-clinical and clinical data including several papers from the Japanese literature. An attempt is made to define what is meant by selectivity at various levels including the test tube, in the laboratory animal and, most importantly, in the clinical context of the whole patient.

CONCLUSIONS

The conclusions are interpreted within the context of the subdivision of the alpha 1-adrenoceptor into alpha 1A, alpha 1B, and alpha 1D subtypes.

Nitric oxide synthase-containing nerves and ganglia in the dog prostate: a comparison with other transmitters

The distribution of nitric oxide synthase immunoreactive nerves in the dog prostate was compared to the total innervation (as estimated by protein gene product 9.5 immunoreactivity), and to that of adrenergic (tyrosine hydroxylase-immunoreactive), cholinergic (acetylcholinesterase-positive), and some peptidergic nerves immunoreactive towards vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide, and helospectin. Clusters of ganglia with cell bodies containing acetylcholinesterase, or one of these six immunoreactive components, were found in the dorsal capsule. Coarse nerve trunks expressing these immunoreactive components extended from the ganglia, and divided into varicose terminals in the capsule and intraglandular smooth muscle strands, and gave off further branches, which surrounded acini and accompanied ducts. The labelling for nitric oxide synthase generally coincided with that for vasoactive intestinal peptide within cell bodies and nerves of various types. Cell bodies, nerve trunks and varicose terminals showing labelling for pituitary adenylate cyclase-activating peptide and helospectin were generally also labelled for vasoactive intestinal peptide. The innervation pattern suggests that nitric oxide may act in concert with vasoactive intestinal peptide and related peptides in the control of prostatic smooth muscle activity and secretion.