Benign prostatic hyperplasia. Current pharmacological treatment

Effects of Alginate Oligosaccharide on Testosterone-Induced Benign Prostatic Hyperplasia in Orchiectomized Rats

Benign prostatic hyperplasia (BPH) is an age-related disease of the urinary system that affects elderly men. Current treatments for BPH are associated with several adverse effects, thus highlighting the need for alternative agents. Alginate oligosaccharide (AOS), a water-soluble functional oligomer derived from brown algae, inhibits prostate cancer cell proliferation. However, the effects of AOS on BPH and the underlying molecular mechanisms remain unclear. Therefore, here, we aimed to investigate the therapeutic potential of AOS in BPH by using human benign prostatic epithelial cells (BPH-1) and a rat model of testosterone-induced BPH. Treatment with AOS inhibited in vitro and in vivo proliferation of prostatic epithelial cells and the testosterone-induced expression of androgen receptor (AR) and androgen-associated genes, such as those encoding 5α-reductase type 2 and prostate-specific antigen. Oral administration of AOS remarkably reduced the serum levels of dihydrotestosterone (DHT) and testosterone as well as the expression of proliferating cell nuclear antigen, inflammatory cytokines, and enzymes, which showed increased levels in prostatic tissues of rats with testosterone-induced BPH. Taken together, these data demonstrate that AOS suppresses testosterone-induced BPH in rats by downregulating AR and the expression of androgen-associated genes, supporting the hypothesis that AOS might be of potential use for the treatment of BPH.

Synthesis and application of 0D/2D nanocomposite for the nanomolar level detection of antiandrogen drug

In this work, Sr@FeNi-S nanostructures were synthesized through chemical approach. The as synthesized nanostructures were explored for the fabrication of a nanocomposite based potentiometric flutamide (FLU) sensor. A conducting graphene...

Unraveling the electrochemical properties of lanthanum cobaltite decorated halloysite nanotube nanocomposite: An advanced electrocatalyst for determination of flutamide in environmental samples

Prostate cancer is one of the primary causes of death around the world. As an important drug, flutamide has been used in the clinical diagnosis of prostate cancer. However, the over dosage and improper discharge of flutamide could affect the living organism. Thus, it necessary to develop the sensor for detection of flutamide with highly sensitivity. In this paper, we report the synthesis of lanthanum cobaltite decorated halloysite nanotube (LCO/HNT) nanocomposite prepared by a facile method and evaluated for selective reduction of flutamide. The as-prepared LCO/HNT nanocomposite shows the best catalytic performance towards detection of flutamide, when compared to other bare and modified electrodes. The good electrochemical performance of the LCO/HNT nanocomposite modified electrode is ascribed to abundant active sites, large specific surface area and their synergetic effects. Furthermore, the LCO/HNT modified electrode exhibits low detection limit (0.002 μM), wide working range (0.009-145 μM) and excellent selectivity with remarkable stability. Meaningfully, the developed electrochemical sensor was applied in real environmental samples with an acceptable recovery range.

A prospective pilotstudy comparing the anesthetic effects of an alpha-2 agonist during holmium laser resection of the prostate and transurethral resection for prostate surgery for benign prostatic hyperplasia patients using selective alpha-1 blockers

BACKGROUND

To examine the response to an α2receptor agonist used as a sedative for patients using long-term selective α1 blockers.

METHODS

Sixty-nine consecutive patients undergoing transurethral prostate resection or holmium laser resection of the prostateunder spinal anesthesia were divided into two groups; group N (n = 37), which did not receive α1 blockers, and group T (n = 32), which was administered tamsulosin for at least 1 month before the study. Bispectral index scores, Modified Observer's Assessment of Alertness/Sedation scale scores, heart rate, and mean blood pressure were obtained under sedation using dexmedetomidine for 30 min during surgery.

RESULTS

The only significant difference found between the groups were mean bloodpressure 15 min after the first loading dose injection of dexmedetomidine. Differencesbetween both groupswere noted at 15 min(group T: 100.2 ± 12.9 mmHg; group N: 90.0 ± 17.5 mmHg; P = 0.08), 20 min (group T: 99.8 ± 12.3 mmHg; group N: 87.4 ± 15.0 mmHg; P < 0.00), 25 min (group T: 99.3 ± 13.4 mmHg; group N: 85.4 ± 13.8 mmHg; P < 0.00), and 30 min (group T: 98.8 ± 13.1 mmHg; group N: 84.5 ± 13.5 mmHg; P < 0.00).

CONCLUSIONS

The use of α2 agonists is appropriate during surgery for benign prostatic hyperplasia patients using tamsulosin, and there is no need to alter the dose. Alertness with anesthesia involving α2 agents was maintained for patients using long-term tamsulosin and patients who did not use tamsulosin.

TRIAL REGISTRATION

The study was retrospectively registered with the Clinical Research Informational Service ( KCT0002967 , July 2, 2018).

S. B. An electrochemical sensing platform for trace recognition and detection of an anti-prostate cancer drug flutamide in biological samples

Systematic illustration of electrode fabrication.

A novel luminol chemiluminescent method catalyzed by silver/gold alloy nanoparticles for determination of anticancer drug flutamide

It was found that silver/gold alloy nanoparticles enhance the chemiluminescence (CL) of the luminol-H2O2 system in alkaline solution. The studies of UV-Vis spectra, CL spectra, effects of concentrations luminol, hydrogen peroxide and silver/gold alloy nanoparticles solutions were carried out to explore the CL enhancement mechanism. Flutamide was found to quench the CL signals of the luminol-H2O2 reaction catalyzed by silver/gold alloy nanoparticles, which made it applicable for the determination of flutamide. Under the optimum conditions, the CL intensity is proportional to the concentration of the flutamide in solution over the range 5.0 × 10(-7) to 1.0 × 10(-4)mol L(-1). Detection limit was obtained 1.2 × 10(-8)mol L(-1)and the relative standard deviation (RSD) γ5%. This work is introduced as a new method for the determination of flutamide in commercial tablets. Box-Behnken experimental design is applied to investigate and validate the CL measurement parameters.

Androgen receptor roles in the development of benign prostate hyperplasia

Benign prostate hyperplasia (BPH) is a major cause of lower urinary tract symptoms, with an increased volume of transitional zone and associated with increased stromal cells. It is known that androgen/androgen receptor (AR) signaling plays a key role in development of BPH, and that blockade of this signaling decreases BPH volume and can relieve lower urinary tract symptoms, but the mechanisms of androgen/AR signaling in BPH development remain unclear, and the effectiveness of current drugs for treating BPH is still limited. The detailed mechanisms of androgen/AR signaling need to be clarified, and new therapies are needed for better treatment of BPH patients. This review focuses on roles of AR in epithelial and stromal cells in BPH development. In epithelial cells, AR may contribute to BPH development via epithelial cell-stromal cell interaction with alterations of epithelial-mesenchymal transition, leading to proliferation of stromal cells. Data from several mouse models with selective knockout of AR in stromal smooth-muscle cells and/or fibroblasts indicate that the AR in stromal cells can also promote BPH development. In prostatic inflammation, AR roles in infiltrating macrophages and epithelial and stromal cells have been linked to BPH development, which has led to discovery of new therapeutic targets. For example, targeting AR with the novel AR degradation enhancer, ASC-J9 offers a potential therapeutic approach against BPH development.

The efficacy and safety of alpha-1 blockers for benign prostatic hyperplasia: an overview of 15 systematic reviews

OBJECTIVE

A great number of clinical trials and systematic reviews have evaluated the efficacy and safety of α(1) blockers for benign prostatic hyperplasia (BPH). We carried out an overview of reviews to provide an up-to-date summary of evidence regarding the efficacy and safety between different α(1) blockers for BPH.

RESEARCH DESIGN AND METHODS

PubMed, EMBASE, the Cochrane Library, China National Knowledge Infrastructure, Chinese BioMedical Literature Database and VIP were searched for eligible studies. Direct evidence was analyzed narratively. We used a random-effects model within a Bayesian framework to calculate indirect estimates if no direct evidence existed. The GRADE approach was used in summarizing conclusions.

RESULTS

A total of 15 systematic reviews involving five α(1) blockers met the inclusion criteria. Direct evidence demonstrated that α(1) blockers were superior to placebo in reducing urinary symptom scores and improving peak urinary flow PUF. Doxazosin could significantly reduce urinary symptom scores compared with tamsulosin mean difference (MD -1.60, 95% CI -1.80 to -1.40) and alfuzosin (MD1.7, 95% CI 0.76-1.64). Indirect evidence suggested that the urinary symptom score and PUF at endpoint in men treated with naftopidil were similar to those treated with other α(1) blockers. α(1) Blockers generally lead to more adverse effects compared with placebo, and those caused by terazosin were more frequent than others.

CONCLUSIONS

α(1) Blockers are more effective than placebo for BPH, doxazosin and tamsulosin seem to be more effective than other α(1) blockers. The adverse effects caused by α(1) blockers are generally mild and well-tolerated.

Silodosin is effective for treatment of LUTS in men with BPH: a systematic review

The aim of this study was to systematically review the evidence on the efficacy and safety of silodosin treatments on lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia (BPH) from randomized controlled trials. We searched PubMed (1966-December 2011), Embase (1974-December 2011) and the Cochrane Library Database (2011, Issue 12). The assessed outcome measures were the change from baseline for the International Prostate Symptom Score (IPSS), quality of life (QoL) score, peak urine maximum flow rate (Q(max)), QoL related to urinary symptoms and adverse effects. Two authors independently assessed the study quality and extracted data. All data were analysed using RevMan 5.1. The meta-analysis included four randomized controlled trials with a total of 2504 patients. The study durations were each 12 weeks. At the follow-up end points, the pooled results showed that the change from baseline for the silodosin group was significantly higher than the placebo group for the IPSS, QoL score and Q(max)(mean difference (MD)=-2.78, P<0.00001; MD=-0.42, P=0.004; MD=1.17, P<0.00001,respectively) and patients felt more satisfied with QoL related to urinary symptoms in the silodosin group than the placebo group. Ejaculation disorder was the most commonly reported adverse effect. The pooled results also showed that the silodosin group was superior to the 0.2 mg tamsulosin group with respect to the IPSS and QoL score (IPSS: MD=-1.14, P=0.02; QoL score: MD=-0.26, P=0.02) and inferior to the 0.2 mg tamsulosin group with respect to Q(max) (MD=-0.85, P=0.01). In contrast, there was no significant difference in the incidence of ejaculation disorder and dizziness between the silodosin and 0.2 mg tamsulosin groups. The current meta-analysis suggested that silodosin is an effective therapy for LUTS in men with BPH and is not inferior to 0.2 mg tamsulosin.

Voltammetric determination of flutamide and its metabolite 4-nitro-3-trifluoromethylaniline at a hanging mercury drop minielectrode

Optimum conditions were found for direct current and differential pulse voltammetric determination of anticancer drug Flutamide and its main metabolite 4-nitro-3-trifluoromethylaniline on a hanging mercury drop minielectrode in mixed Britton–Robinson buffer (pH 12.0)–methanol (9:1) or 0.01MNaOH–methanol (9:1) media with limit of quantitation ca. 10–7mol l–1. It was proved that the newly developed method is applicable for the determination of Flutamide in pharmaceutical formulations and for the determination of both Flutamide and 4-nitro-3-trifluoromethylaniline in urine either directly with limit of quantitation ca. 10–5mol l–1or after solid phase extraction with limit of quantitation in the 10–7mol l–1concentration range. The sufficient peak potential difference of the two substances suggests the possibility of the analysis of their mixtures.

Benign prostatic hyperplasia: An overview of existing treatment

Benign prostatic hyperplasia (BPH) is the most common condition in aging men, associated with lower urinary tract symptoms (LUTS). A better understanding of the prostate physiology, function, and pathogenesis has led to the development of promising agents, useful in the management of LUTS in men. The specific approach used to treat BPH depends upon number of factors like age, prostrate size, weight, prostate-specific antigen level, and severity of the symptoms. 5α-reductase inhibitors decrease the production of dihydrotestosterone within the prostate, which results in decreased prostate volume, increased peak urinary flow rate, improvement of symptoms, decreased risk of acute urinary retention, and need for surgical intervention. α(1)-adrenergic receptor (α(1)-AR) antagonists decrease LUTS and increase urinary flow rates in men with symptomatic BPH, but do not reduce the long-term risk of urinary retention or need for surgical intervention. Clinical efficacy of either 5α-reductase inhibitor or α(1)-AR antagonist has been further improved by using combination therapy; however, long-term outcomes are still awaited. Many more potential new therapies are under development that may improve the treatment of BPH. This article gives a brief account of rationale and efficacy of different treatment options presently available in the management of BPH.

Hormesis and medicine

Evidence is presented which supports the conclusion that the hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences, being highly generalizable across biological model, endpoint measured and chemical class and physical agent. The paper provides a broad spectrum of applications of the hormesis concept for clinical medicine including anxiety, seizure, memory, stroke, cancer chemotherapy, dermatological processes such as hair growth, osteoporosis, ocular diseases, including retinal detachment, statin effects on cardiovascular function and tumour development, benign prostate enlargement, male sexual behaviours/dysfunctions, and prion diseases.

Impact of Physicochemical and Structural Properties on the Pharmacokinetics of a Series of α1L-Adrenoceptor Antagonists

A rational drug discovery process was initiated to design a potent and prostate-selective alpha1(L)-adrenoceptor antagonist with pharmacokinetic properties suitable for once a day administration after oral dosing, for the treatment of benign prostatic hyperplasia. Two series of compounds based on a quinoline or quinazoline template were identified with appropriate pharmacology. A series of high molecular weight cations with high hydrogen-bonding potential had extensive in vivo clearance, despite demonstrating metabolic stability. Studies in the isolated perfused rat liver and fresh rat hepatocytes indicated that active transport protein-mediated hepatobiliary elimination is an efficient clearance process for these compounds. A reduction in molecular weight and hydrogen-bonding potential resulted in a second series of compounds with in vivo hepatic clearance predictable from in vitro metabolic clearance. Initially, lipophilicity was reduced within this second series to reduce metabolic clearance and increase elimination half-life. However, this strategy also resulted in a concomitant reduction in volume of distribution and a negligible effect on prolonging half-life. An alternative strategy was to increase the intrinsic metabolic stability of the molecule by careful structural modifications while maintaining lipophilicity. Replacement of the metabolically vulnerable morpholine side chain resulted in identification of UK-338,003, (N-[2-(4-amino-6,7-dimethoxy-5-pyridin-2-yl-quinazolin-2-yl)-1,2,3,4-tetrahydro-isoquinolin-5-yl]-methanesulfonamide), which fulfilled the objectives of the discovery program with suitable pharmacology (human prostate alpha1(L) pA(2) of 9.2 with 25-fold selectivity over rat aorta alpha1(D)) and sufficiently long elimination half-life in human volunteers (11-17 h) for once a day administration.

Effect of D-004, a Lipid Extract from the Cuban Royal Palm Fruit, on Atypical Prostate Hyperplasia Induced by Phenylephrine in Rats

BACKGROUND AND OBJECTIVE

Benign prostatic hyperplasia (BPH) is a non-malignant enlargement of the prostate that results in obstructive lower urinary tract symptoms. Saw palmetto (Serenoa repens), the dwarf American palm (Arecaceae family), is commonly used to treat BPH. The Cuban royal palm (Roystonea regia) also belongs to the Arecaceae family, and 200-400mg of D-004, a lipid extract from its fruits, administered orally for 14 days has been shown to prevent testosterone- but not dihydrotestosterone-induced prostatic hyperplasia in rats. D-004 (125-250 microg/mL) added to preparations of rat vas deferens caused a marked, dose-dependent and significant inhibition of noradrenaline-induced smooth muscle contraction, a response mediated through alpha(1)-adrenoceptors, and was more effective in these respects than Saw palmetto. However, the in vivo effects of D-004 and Saw palmetto on the hypertensive response induced by noradrenaline were modest (albeit significant), and neither treatment affected resting blood pressure or heart rate in rats. The differential effects of D-004 in in vitro and in vivo models could be related to a differential affinity for adrenoceptor subtypes or to different bioavailabilities in vascular and urogenital targets. Phenylephrine injected into rodents induces prostatic hyperplasia with all the characteristic morphological changes of the condition but does not result in enlargement of the prostate. Therefore, this phenylephrine-induced change in rat prostate tissue is called atypical prostatic hyperplasia. It serves as an in vivo model of prostatic hyperplasia induced by stimulation of alpha(1)-adrenoceptors. The objective of this study was to determine whether D-004 can inhibit induction of atypical prostatic hyperplasia by phenylephrine in rats.

METHODS

Rats were randomly distributed into five groups (ten rats/group). One group was a negative control and received oral vehicle only. The other four groups were injected subcutaneously with phenylephrine (2 mg/kg): of these groups, one was a positive control receiving the vehicle, and the other three groups were treated with D-004 or Saw palmetto (both 400 mg/kg) or tamsulosin 0.4 mg/kg. All active treatments were given orally for 28 days. After completion of treatment, rats were placed unrestrained in metabolic cages and micturition studies were performed. The rats were later killed and their prostates removed and weighed. Prostate samples were processed for histological study, with histological changes being assessed according to a scoring system. Bodyweight was measured at baseline and at weekly intervals.

RESULTS

Histological examination of positive control rats revealed features of atypical prostatic hyperplasia, with piling-up, papillary and cribiform patterns and budding-out of epithelial cells. Micturition assessment revealed that phenylephrine significantly lowered both the total volume of urine in 1 hour and the volume per micturition; the latter was considered the main efficacy variable. D-004 and Saw palmetto extracts significantly prevented this reduction in volume per micturition by 70.5% and 68.6%, respectively, while tamsulosin totally abolished the reduction in micturition induced by phenylephrine (100% inhibition). Tamsulosin, D-004 and Saw palmetto significantly reduced the histological changes of atypical prostatic hyperplasia induced by phenylephrine by 73.1%, 61.2% and 50.0%, respectively.

CONCLUSIONS

Administration of D-004 resulted in marked and significant prevention of phenylephrine-induced impairment of micturition and histological changes in rat prostate. These findings indicate that, in vivo, D-004 effectively opposes these responses to phenylephrine, which are mediated through urogenital alpha(1)-adrenoceptors. In this respect, D-004 was moderately more effective than Saw palmetto, a phytotherapeutic standard used to treat BPH, but less effective than tamsulosin, a selective alpha(1A)-adrenoceptor antagonist.

Electro-Spinning and Electro-Blowing of Hyaluronic Acid

In this study, hyaluronic acid (HA) was electro-spun and electro-blown to prepare nonwoven nanofibrous membranes. Critical parameters for processing and corresponding effects on the membrane morphology were investigated using the methods of rheology and scanning electron microscopy (SEM). During electro-spinning, the optimal HA concentration window for nanofibrous formation was determined within a narrow range of 1.3-1.5 w/v %, corresponding to a solution viscosity range of 3-30 Pa s at a shear rate of 1 s(-1). SEM results indicated that, with increases in (1) the total concentration by blending of low molecular weight HA, (2) the evaporation rate by the addition of ethanol, and/or (3) the feeding rate of solution, the electro-spinning performance for creating nanofibers was improved. However, the improvement was not sufficient to achieve a consistent production of high quality nonwoven nanofiber membranes. This problem was overcome by a new electro-blowing process using the combination of air flow and electro-spinning. Although air blowing at room temperature around the spinneret orifice did not exhibit a remarkable enhancement of nanofiber formation of HA, the performance was significantly improved with an increase in the air blowing rate. SEM results showed that the temperature of air-blowing was the most effective parameter in ensuring HA nanofiber formation. As the temperature of the blown air increased from 25 to 57 degrees C, the nanofiber formation became consistent and uniform. A high quality HA nonwoven membrane of nanofibers was successfully produced by blowing air at 57 degrees C with a 70 ft(3)/hr flow rate.

Increased expression of CYR61, an extracellular matrix signaling protein, in human benign prostatic hyperplasia and its regulation by lysophosphatidic acid

Lysophosphatidic acid (LPA) is an endogenous lipid growth factor that is thought to play important roles in cell proliferation and antiapoptosis and therefore may have roles in the development and progression of benign prostatic hyperplasia (BPH). CYR61 (CCN1), on the other hand, is a growth factor-inducible immediate early gene that functions in cell proliferation, differentiation, and extracellular matrix synthesis. Here we show the close relationship between LPA-induced expression of CYR61 and prostate enlargement. CYR61 mRNA and protein were dramatically up-regulated by 18:1 LPA (oleoyl-LPA) within 1 and 2 h, respectively, in both stromal and epithelial prostatic cells. G protein-coupled receptors, i.e. Edg-2, Edg-4, and Edg-7, for LPA were also expressed in both stromal and epithelial prostatic cells. Furthermore, on DNA microarray analysis for normal and BPH patients, CYR61 was found to be related to the development and progression of BPH, regardless of symptoms. Although CYR61 mRNA was synthesized in hyperplastic epithelial cells, in many cases of BPH, CYR61 protein was detected in both the epithelial and stromal regions of BPH patient tissues. The functional contribution of CYR61 to prostatic cell growth was demonstrated by recombinant CYR61 protein and anti-CYR61 neutralizing antibodies, which inhibited CYR61-dependent cell spreading and significantly diminished cell proliferation, respectively. In conclusion, these data support the hypothesis that LPAs induce the expression of CYR61 by activating G proteincoupled receptors and that CYR61 acts as a secreted autocrine and/or paracrine mediator in stromal and epithelial hyperplasia, demonstrating the potential importance of this signaling mechanism in the disease.

Multiple dose pharmacokinetics of fiduxosin under fasting conditions in healthy elderly male subjects

Selective alpha1a-adrenoceptor antagonists are effective agents for treatment of benign prostatic hyperplasia, a disorder occurring in middle-aged and elderly males. The objective of this study was to determine the pharmacokinetics of fiduxosin, a novel alpha1a-adrenoceptor antagonist, following multiple dose administration. This was carried out in a Phase I, randomized, double-blind, placebo-controlled, parallel group, multiple oral dose study of fiduxosin. Single once-daily oral doses of 30, 60, 90 or 120 mg of fiduxosin or placebo were administered to healthy elderly male subjects (n = 48; 8 active and 4 placebo per dosing group) for 14 consecutive days. Fiduxosin plasma concentration-versus-time profiles for days 1, 7 and 14 were used to assess fiduxosin pharmacokinetics. Steady state was achieved by day 7. At steady-state mean Tmax (time to maximum plasma concentration), CL/F (apparent oral clearance) and Vbeta/F (apparent volume of distribution) ranges were 1.8-7.8 h, 27.3-47.2 L h(-1) and 846-1399 L, respectively. Tmax and VbetaF were independent of dose. Cmax (maximum plasma concentration), Cmin (minimum plasma concentration) and AUC24 (area under plasma concentration vs time curve from 0 to 24 h) for days 7 and 14 were linearly proportional with dose overthe 30-120 mg/day dose range and were unchanged from day 7 to day 14. It was concluded that fiduxosin multiple-dose pharmacokinetics were dose-independent and time-invariant over the 30-120 mg/day dose range under fasting conditions.

Single- and multiple-dose pharmacokinetics of fiduxosin under nonfasting conditions in healthy male subjects

Selective alpha1a-adrenoreceptor antagonists are effective agents for treatment of benign prostatic hyperplasia, a disorder occurring in middle-aged and elderly males. The objective of this study was to determine the single- and multiple-dose pharmacokinetics of fiduxosin, a novel, selective alpha1a-adrenoreceptor antagonist. This was a Phase I, randomized, double-blind, placebo-controlled, parallel-group, single and multiple oral dose study of fiduxosin. Single daily oral doses of 30, 60, or 90 mg of fiduxosin or placebo were administered to healthy adult male subjects (N = 36; 8 active and 4 placebo per dosing group) on Day 1 and Days 5 to 11 (7 consecutive days) after a high-fat breakfast. Fiduxosin plasma concentration-time profiles for Days 1 and 11 were used to assess fiduxosin pharmacokinetics. Fiduxosin single-dose and steady-state pharmacokinetics were dose independent after oral administration under nonfasting conditions. Steady state was achieved after 4 days of qd dosing. Approximately 28% of the oral dose was eliminated by the fecal route as unchanged drug. Less than 1% of the unchanged drug was recovered in the urine after oral administration.

Efficacy and tolerability of drugs for treatment of benign prostatic hyperplasia

It has long been recognised that neural factors are of considerable importance in lower urinary tract function. Whilst reduction in the bulk of the human prostate is feasible, experience on this therapeutic approach proved to be disappointing. Existing trial data with the agent finasteride are reviewed. A number of formulations derived from plant extracts have been advocated but their mechanism of action remain largely obscure and there is a dearth of placebo controlled information to support their efficacy. Experience over the last 10 years has demonstrated efficacy with the use of alpha adrenoceptor blockade in the management of BPH. Alpha adrenoceptor antagonists relax the prostatic smooth muscle by interrupting the sympathetic pathway at the receptor level. Recent developments in this field include the recognition that there are alpha I adrenoceptor subtypes. The functional adrenoceptor in the human prostate is predominantly the alpha IA - subtype. Of the alpha 1-adrenoceptor antagonists only tamsulosin discriminates between the alpha 1-adrenoceptor subtypes. Alpha 1-blockers should be used in first-line medical therapy for BPH and 5-alpha-reductase inhibitors reserved for those patients in whom alpha-blocker therapy fails. Alpha I-blockers such as doxazosin, tamsulosin, terazosin, alfuzosin are effective in the treatment of BPH both in younger and in older men. The drugs are well tolerated. The majority of side effects were classified as minor and mild. The most common complaints, as with other alpha-blockers, are dizziness, fatigue and headache, and these are often transient. In contrast, finasteride can lead to impotence, reduced libido. gynaecomastia or ejaculatory disorders. Men with small prostates may not be suitable candidates for finasteride therapy.

Effect of food on the pharmacokinetics of fiduxosin in healthy male subjects

The effect of food on the pharmacokinetics of fiduxosin, a novel selective alpha1a-receptor antagonist, was determined in healthy male subjects. This was a Phase I, open-label, single-center, randomized, two-period, crossover, single oral dose study of fiduxosin. Healthy male subjects (N= 14) were administered single oral doses of 30 mg of fiduxosin under fasting or nonfasting (1026 Kcal, 54 g fat, 46% calories from fat) conditions in each period. Fiduxosin plasma concentration profiles were used to assess fiduxosin pharmacokinetics. The mean Cmax, Tmax, AUC(infinity), CL/F and Vbeta/F values under fasting and nonfasting conditions were 34.3 and 150 ng/mL, 5.4 and 5.4 h, 822 and 1940 ng x h/mL, 42.5 and 17.2 L/h, and 924 and 235 L, respectively. The harmonic mean t 1/2 under fasting and nonfasting conditions were 13.9 and 9.28 h, respectively. Food significantly increased the bioavailability of fiduxosin. Under the nonfasting regimen, the Cmax central value was more than 4-fold and the AUC(infinity) central value more than 2-fold the central value of the fasting regimen. Tmax was not significantly different between fasting and nonfasting regimens. Food also decreased fiduxosin oral clearance (CL/F) by 60% and volume of distribution (Vbeta/F) by 75%.

Separation of finasteride and analogues

This review is focused on the different chromatographic strategies for determination of finasteride and its analogues in biological fluids. These compounds are used for the treatment of benign prostatic hyperplasia. Particular attention is paid to high-performance liquid chromatography with spectrophotometric and mass spectrometric detection, the clean-up procedures are also included. The relationships between pharmacokinetics of finasteride, dose administered and required limit of quantitation of the chromatographic assays are discussed. Tandem mass spectrometry is recommended as the detection method for measuring concentrations <1 ng/ml, while cheaper spectrophotometric detection may be selected for determination of higher concentrations.

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.

Hormonal effects of Z-350, possessing steroid 5alpha-reductase inhibitory and alpha1-adrenoceptor antagonistic actions, in the rat

We examined the hormonal effects of Z-350, (S)-4-[3-(4-[1-(4-methylphenyl)-3-[4-(2-methoxyphenyl)piperazine-1-yl]propoxy]benzoyl)indole-1-yl]butyric acid hydrochloride, which has both alpha1-adrenoceptor blocking activity and steroid 5alpha-reductase inhibitory activity, in male and female rats. Z-350 administered orally for 14 days at a dose of 30 mg/kg to normal male rats significantly reduced the weight of the prostate and seminal vesicles without affecting the weight of the testis, epididymis, adrenals, kidney or liver. Prostatic levels of dihydrotestosterone decreased dose-dependently, with a slight increase in the level of testosterone at a Z-350 dose of 100 mg/kg. We observed no effects on the weight of the prostate in castrated rats or on the weight of the uterus in normal or 17beta-estradiol-treated female rats. These results suggest that Z-350 inhibits prostatic growth via inhibition of steroid 5-reductase without other hormonal effects.

The role of alpha(1)-adrenoceptors and 5-HT(1A) receptors in the control of the micturition reflex in male anaesthetized rats

1. The effects of the alpha(1)-adrenoceptor antagonists doxazosin (0.1 -- 2 mg kg(-1)), RS-100329 (alpha(1A); 0.01 -- 1 mg kg(-1)), RS-513815 (Ro 151-3815, alpha(1B); 0.3 -- 3 mg kg(-1)) and BMY 7378 (alpha(1D); 0.1 -- 1 mg kg(-1)), the 5-HT(1A) receptor agonist, 8-OH-DPAT (0.03 -- 0.3 mg kg(-1)) and antagonist WAY-100635 (0.03 -- 0.3 mg kg(-1)) were investigated (i.v.) on the 'micturition reflex' in the urethane anaesthetized male rat. 2. Reflex-evoked urethra contractions were most sensitive to the inhibitory action of RS-100329, followed by doxazosin, BMY 7378 and WAY-100635 and then RS-513815. The maximum inhibition was 66, 63, 54, 46 and 22% at doses of 0.3, 0.5, 0.3, 0.3 and 3 mg kg(-1) respectively. 3. BMY 7378 and 8-OH-DPAT decreased, while WAY-100635 increased, the pressure threshold to induce bladder contraction. WAY-100635 (0.01 mg kg(-1)) blocked the effects of BMY 7378 (1 mg kg(-1)) on bladder pressure and volume threshold. 4. Doxazosin, RS-100329 and BMY 7378 had a similar potency in inducing a fall in arterial blood pressure while WAY-100635 only caused a fall at the highest dose. 5. Therefore, reflex-evoked urethral contraction involves the activation of alpha(1A/1D)-adrenoceptors, as BMY 7378 and RS-100329 are similarly potent in attenuating this effect. The ability of WAY-100635 to attenuate this contraction may suggest that 5-HT(1A) receptors are also involved. However, as this inhibition occurred at the highest dose of WAY-100635, which also caused a fall in arterial blood pressure; this effect is considered to be due to blockade of alpha(1)-adrenoceptors not 5-HT(1A) receptors. Nevertheless the initiation of the 'micturition reflex' involves the activation of 5-HT(1A) receptors.

Determination of immunoreactive gonadotropin-releasing hormone in serum and urine by on-line immunoaffinity capillary electrophoresis coupled to mass spectrometry

The need for urgent diagnoses has propelled the development of automated analyses that can be performed in a short time at reasonable cost. One such method is immunoaffinity capillary electrophoresis. This emerging hybrid technology employs two powerful techniques coupled on-line for the direct and rapid determination of analytes present in biological fluids. The first technique, immunoaffinity, is used for the selective extraction of a molecule present in a complex matrix, utilizing a microscale-format chamber affinity device. An analyte (affinity target) present in serum or urine is captured by an immobilized molecular recognition antibody molecule (affinity ligand) bound to a solid support constituent (glass beads or an appropriate porous structure) of a microchamber affinity device. The second technique, capillary electrophoresis, is used for the high-resolution analytical separation of the purified and concentrated affinity target material after elution from the microchamber affinity device. In this work, immunoaffinity capillary electrophoresis was developed for the identification and characterization of a single constituent of a complex matrix. Immunoreactive gonadotropin-releasing hormone was determined in serum and urine specimens derived from a normal individual and from a patient suffering from benign prostatic hyperplasia. Furthermore, the on-line immuno-separation system was coupled in tandem to mass spectrometry to obtain molecular mass information of the affinity isolated and CE separated neuropeptide. This hybrid immuno-analytical technology is simple, rapid, selective and sensitive. In addition, an attempt was also made to characterize other urinary constituents by CE-MS that may lead to marker activity in the urine of the diseased subject. The hyphenation of analytical techniques has proved valuable in enhancing their individual features. The future of bioanalysis using miniaturized affinity systems is discussed in this paper.

[Cost-effectiveness analysis of the treatment of moderate benign prostatic hyperplasia]

OBJECTIVES

To estimate the most cost-effective alternative of treatment of moderate benign prostatic hyperplasia and to learn whether the outcome can be varied by changing the cost or effectiveness of the alternatives.

DESIGN

The study is made by a decision tree in order to test the cost-effectiveness (CE) rate of three treatment strategies: a) watchful waiting; if there is no response a drug is administered and if there is no response transurethral resection of the prostate (TURP) is done, b) pharmacological treatment, and if there is no response TURP is done, and c) to apply TURP initially. The treatment is simulated taking 1000 patients with MBPH and testing the outcome of events and probabilities in a two-year treatment and from the point of view of the health system as services supplier.

MEASUREMENTS AND RESULTS

Effectiveness is obtained from an american experts' consensus. Only the direct fangible costs are taken into account, in constant 1998 pts. An univariant simple sensitivity analysis is made considering the cost variables of TURP and from the drugs in an acceptable range of +/- 20%, and the effectiveness of the watchful waiting and the pharmacological treatment. The lower cost alternative per improved patient (IP) is the watchful waiting (77,069 pts./IP) followed by the drug treatment (118,656 pts./IP) and lastly the TURP (456,642 pts./IP). Variations in the variable values make no difference in the relative positions of the tested alternatives.

CONCLUSIONS

From the pharmacoeconomics point of view the MBPH treatment must be iniciated by watchful waiting, proceeding to drug administration only if there is a positive response and to make use of TURP when the pharmacological procedures have not been effective.

Alpha-adrenergic blocking drugs in the management of benign prostatic hyperplasia: interactions with antihypertensive therapy

Management of benign prostatic hyperplasia (BPH) is often complicated by concomitant hypertension, a life-threatening condition that must be managed optimally. Many of the alpha blockers used to treat BPH also decrease blood pressure, and terazosin and doxazosin have been shown to have significant cardiovascular side effects, such as asthenia/fatigue, postural hypotension, and dizziness when used to treat BPH patients. Furthermore, these drugs are not first-line therapies for hypertension, and the majority of hypertensive BPH patients will be receiving other antihypertensive agents. Therefore, it is possible that the introduction of these drugs will affect blood pressure control, at least temporarily, with possible adverse effects. In contrast, the selective alpha1A blocker tamsulosin does not appear to have significant cardiovascular side effects and produces minimal blood pressure reductions. Therefore, urologists can choose either to use alpha blockers to treat both hypertension and BPH or to treat BPH using alpha blockers that do not interact with antihypertensive therapy. This review focuses on the alpha blockers currently being used to treat BPH, their effects on the cardiovascular system, and their interaction with antihypertensive drugs.

Efficacy and acceptability of tadenan (Pygeum africanum extract) in the treatment of benign prostatic hyperplasia (BPH): a multicentre trial in central Europe

Pygeum africanum extract is available as Tadenan in many countries, including those in central and eastern Europe, for the treatment of mild to moderate BPH. Its efficacy and acceptability have been demonstrated in numerous open and placebo-controlled studies in large populations. The present open three-centre efficacy and safety study was conducted according to common protocol at urology clinics in the Czech and Slovak Republics and in Poland, in order to confirm the therapeutic profile of Pygeum africanum in conditions of daily practice, using International Prostate Symptom Score (IPSS) and flowmetry assessments. Men aged 50-75 years and in compliance with the selection criteria (including IPSS > or = 12, quality of life (QoL) score > or = 3, and maximum urinary flow < or = 15 ml/s) were first examined then recalled after two weeks during which no treatment was provided (washout and check of stability). If still compliant, they were entered at this point into a two-month period of treatment with Pygeum africanum extract 50 mg twice daily. There followed a further one-month period without treatment, the objective being to evaluate the persistence of any effects observed during the previous two months of Pygeum africanum administration. The primary efficacy parameter investigated was IPSS; the other efficacy parameters were QoL, nocturnal frequency, maximum urinary flow, average urinary flow, post-voiding residual volume and prostatic volume, after one and two months of Pygeum africanum treatment and one month after stopping treatment. A total of 85 patients were evenly distributed between the three centres and completed the entire study. At inclusion their mean IPSS was 16.17, QoL was 3.60 and nocturia was 2.6 times per night. The changes in subjective scores, IPSS and QoL after the two-month treatment period were highly statistically significant with mean improvements of 40% and 31%, respectively. Nocturnal frequency was reduced by 32% and the mean reduction was again highly statistically significant. Mean maximum urinary flow, average urinary flow and urine volume were also statistically significantly improved, but the modest improvement in post-voiding volume did not reach statistical significance. The improvements, which exceeded those observed with placebo in earlier studies, were maintained after one month without treatment indicating an interesting persistence of clinically useful activity. Prostatic volume and quality of sexual life remained unchanged throughout. No treatment-related adverse effects were observed. In conclusion, under conditions of daily practice, Pygeum africanum extract induces significant improvement in IPSS and uroflowmetry parameters. These positive effects are accompanied by a very satisfactory safety profile with the overall result of a substantial improvement in QoL.

Trends in alpha-blocker treatment of patients with benign prostatic hyperplasia and hypertension: dosing regimens and cost comparisons

Dosing regimen is an important determinant of both drug cost and patient compliance. This retrospective analysis evaluated dosing regimens and drug acquisition costs for 101 patients identified from medical records in a large metropolitan hospital as having hypertension and/or benign prostatic hyperplasia and receiving alpha-blocker therapy with either doxazosin or terazosin. Although once-daily administration is generally recommended for both drugs, 25 (38%) of 66 patients receiving terazosin were treated twice daily compared with 6 (17%) of 35 patients treated twice daily with doxazosin. This difference was statistically significant. The average (mean +/- SD) daily treatment cost per patient for all individuals receiving terazosin during the period of the record review was $1.68 +/- 0.60. For patients treated with doxazosin, the average was $0.96 +/- 0.65-a highly statistically significant result. If all 66 patients receiving terazosin had been converted to doxazosin at the beginning of the study, annual savings would have been $17,345.00. These results demonstrate the importance of reviewing actual dosing regimens. The fact that doxazosin could be administered to a significantly higher percentage of patients once daily rather than twice daily substantially decreased its cost relative to terazosin. A once-daily treatment regimen may also enhance patient compliance, thereby improving the chances of therapeutic success.

Benign prostatic hyperplasia: diagnosis and treatment guideline

OBJECTIVE

To critique the US Department of Health and Human Services Public Health Service, Agency for Health Care Policy and Research, Clinical Practice Guideline on Benign Prostatic Hyperplasia: Diagnosis and Treatment; and to provide an update on management and treatment of benign prostatic hyperplasia (BPH) since the Guideline was published.

DATA SOURCES

A review of the published medical literature in MEDLINE from 1994 to April 1996, limited in focus to drug treatment of BPH, English language, and human subjects, was performed.

STUDY SELECTION

Controlled clinical studies of drug treatment for symptomatic BPH that used objective parameters (e.g., urinary flow rate, prostatic volume, voiding symptom scores) were evaluated. A single reviewer assessed each study.

DATA EXTRACTION

Study methods, inclusion and exclusion criteria, and treatment outcomes were assessed for all studies. Independent extraction was performed by a single observer.

DATA SYNTHESIS

Management of BPH is directed at ameliorating voiding symptoms. For moderate or severe BPH, medical or surgical therapy should be offered to the majority of patients. Medical therapy options include alpha-adrenergic antagonists and finasteride. The former offer the advantage of a more prompt onset of action (within weeks) when compared with finasteride. Finasteride produces a lower response rate and smaller improvement in voiding symptoms. Combination therapy of terazosin and finasteride has not been proven to be more effective than terazosin monotherapy.

CONCLUSIONS

When medical therapy is indicated for moderate or severe BPH, alpha-adrenergic antagonists exhibit a faster onset of action and produce greater improvement of voiding symptoms than does finasteride.

Treatment of benign prostatic hyperplasia. A pharmacoeconomic perspective

Men with moderate symptoms of benign prostatic hyperplasia (BPH) are the best candidates for medical treatment, while surgery is usually indicated for patients with severe symptoms. Men with mild symptoms do not usually need treatment, but they might be re-evaluated annually if desirable. Finasteride, which produces selective hormonal deprivation, is now established as a well tolerated drug for the long term medical therapy of BPH. Recent studies suggest that finasteride is most effective in men with large prostates (> 40 ml), and the drug should probably be reserved for these patients. alpha-Blockers work in men with small or large prostates, and their rapid onset of action facilitates the identification of responders. alpha-Blockers are more effective than finasteride during the first year of treatment, but only finasteride induces regression of the prostate and offers increased efficacy over time. Even if drug therapy reduces the need for prostate surgery, the total economic cost of BPH treatment is likely to rise because of the increasing application of medical treatment. The magnitude of this increase depends largely on what percentage of the male population embark on long term therapy, at what age treatment is started, and how successful it is. At present, the answers to these questions are largely unknown. The personal economic expenses for men who begin long term medical therapy will probably be an important factor in deciding how common drug treatment for BPH will become in the future. For many men, the main benefit of drug treatment will be the relief of urinary symptoms, but whether this improvement is substantial enough to improve their overall quality of life has not yet been clearly demonstrated in controlled studies.

Doxazosin for benign prostatic hyperplasia: long-term efficacy and safety in hypertensive and normotensive patients. The Multicenter Study Group

PURPOSE

We evaluated the sustained efficacy and safety of doxazosin for long-term treatment (up to 48 months) of normotensive and hypertensive patients with benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

A total of 272 normotensive and 178 mildly to moderately hypertensive men entered a long-term extension study of doxazosin therapy (1 to 8 and 1 to 12 mg. 1 time daily, respectively) for BPH following participation in double-blind, placebo controlled studies. The starting dose of doxazosin was 1 mg. with upward titrations at 2-week intervals to a stable, efficacious and well tolerated dose. At the time of data analysis patients had received between 1 and 48 months of stable dose doxazosin therapy (mean 668 days for normotensive and 807 for hypertensive patients). Mean daily doses were 4 and 6.4 mg. for normotensive and hypertensive men, respectively.

RESULTS

At the end point analysis doxazosin treatment resulted in significant increases above baseline in maximum and average urinary flow rates (1.9 and 1.0 ml. per second, respectively). As assessed by the patient, total, obstructive and irritative BPH symptoms also improved significantly with doxazosin treatment. In the 28 patients who completed 45 to 48 months of treatment improvement in symptom bothersomeness (13.2%) was similar to that of the overall group at the end point (14.8%). Sustained blood pressure decreases (approximately 8/11 mm. Hg systolic/diastolic blood pressure) with doxazosin were statistically and clinically significant in hypertensive patients. Blood pressure decreases in normotensive patients were not clinically significant (approximately 4/2 mm. Hg) and few withdrew from study for reasons related directly to decreased blood pressure or hypotension. Changes in heart rate were not significant. Doxazosin was well tolerated with almost 90% of adverse experiences considered mild or moderate in severity. The most common adverse events were dizziness, headache and fatigue in normotensive and hypertensive patients.

CONCLUSIONS

In this study long-term doxazosin treatment was significantly effective and well tolerated for treating BPH in normotensive and hypertensive patients.

Effect of KMD-3213, an alpha 1a-adrenoceptor-selective antagonist, on the contractions of rabbit prostate and rabbit and rat aorta

KMD-3213, (-)-(R)-1-(3-hydroxypropyl)-5-[2-[[2-[2-(2,2,2-trifluoroethoxy) phenoxy]ethyl]amino]propyl]indoline-7-carboxamide, a newly synthesized alpha 1-adrenoceptor antagonist, has been shown to have potent action toward, and to be selective for human cloned and native alpha 1-adrenoceptors. In the present study, we characterized the inhibitory effect of KMD-3213 on the phenylephrine (alpha 1-adrenoceptor-selective agonist)-induced contraction of rabbit prostate, rabbit thoracic aorta and rat thoracic aorta to functionally confirm the tissue selectivity of KMD-3213. The mean pA2 value for KMD-3213 for the inhibition of the rabbit prostatic contraction was 10.05, whereas the values for the rabbit and rat aortic contractions were 9.36 and 8.13, respectively. The order of mean pA2 values for the inhibition of the rabbit prostatic contraction was KMD-3213 > or = tamsulosin >> prazosin, whereas that for the rabbit and rat aortic contractions was tamsulosin > KMD-3213 > prazosin and tamsulosin > or = prazosin >> KMD-3213, respectively. KMD-3213 produced a sigmoidal inhibition curve for single-dose phenylephrine-induced contractions of rabbit prostate, whereas it produced a non-sigmoidal curve for that of rabbit aorta. KMD-3213 had no effect on isoproterenol-induced chronotropic action in guinea-pig atria, and 5-hydroxytryptamine-, histamine- and acetylcholine-mediated contractions of rabbit aorta. These results indicate that the potency of the inhibitory activity of KMD-3213 depends on the tissue subtype expression and that KMD-3213 preferentially antagonizes prostatic contraction.

Tamsulosin and chlormadinone for the treatment of benign prostatic hyperplasia. The Kobe University YM617 Study Group

The recent introduction of selective alpha-adrenoceptor blockers adds a further therapeutic option for the treatment of benign prostatic hyperplasia (BPH). Tamsulosin, a selective alpha 1-blocker, has proved effective in relieving irritative and obstructive symptoms caused by BPH. To investigate whether the combination of tamsulosin with the anti-androgenic drug chlormadinone is of further therapeutic benefit, 80 patients randomly received tamsulosin 0.2 mg daily, chlormadinone 50 mg daily or a combination of tamsulosin 0.2 mg and chlormadinone 50 mg daily for 16 weeks. Greater improvement in subjective symptoms of BPH was obtained with either tamsulosin alone or in combination with chlormadinone than with chlormadinone alone. However, the greatest improvement in objective uroflowmetric data was obtained with chlormadinone in combination with tamsulosin. Thus, the combination of tamsulosin with chlormadinone appears to be more beneficial than either of these agents used as monotherapy. Further investigation is required to fully evaluate the therapeutic effects of this combination. After the trial period one-third of the chlormadinone and tamsulosin/chlormadinone-treated patients needed no further treatment due to the satisfactory relief of symptoms. At 12 months follow-up, however, one-fourth of the patients had undergone transurethral resection of the prostate (TUR-P) regardless of medication. This suggests a limitation of the medical treatment of BPH.

Androgens are not major down-regulators of androgen receptor levels during growth of the immature rat penis

This study was undertaken to investigate the prevalent hypothesis that androgens are responsible for the organ-specific down-regulation of penile androgen receptors (ARs) and decline of penile growth in the rat during sexual maturation. Sexually immature male rats (21 days old) were castrated and treated for 3 days ("short-term"), with high doses of: (a) testosterone and the alpha-reductase inhibitor finasteride (T/F); (b) dihydrotestosterone (DHT); or (c) finasteride alone (F). Intact and castrate controls received vehicle only. PolyA + RNA was analysed by Northern blot hybridization and ARs were estimated in the penis and ventral prostates by (3-H)R-1881 binding in the cytosol. Short-term castration, with or without F, increased penile AR mRNA, whereas high doses of T/F and DHT reduced it considerably. Although penile cytosol AR concentration in the control castrates, with or without F, paralleled the AR mRNA rise, treatment with androgens left cytosol AR content per organ and AR concentration above those of the intact rat penis despite the drop in AR mRNA. A "long-term" treatment (10 days) on 19-day-old rats with either medium or high doses of T/F and DHT also failed to down-regulate penile cytosol ARs below the intact controls. Western blot analysis of penile cytosol AR levels confirmed these results. Block of pituitary FSH and LH release by a GnRH antagonist in castrates receiving T/F or DHT at high doses did not modify the response. In the case of intact rats, high doses of T/F or DHT actually increased penile cytosol AR content. No difference was observed between T/F and DHT effects. In contrast to what occurs during sexual maturation, the prostate ARs and growth rate responded to all treatments in a similar way to what was observed in the penis. Our results suggest that increases in serum T or DHT are not major factors in the physiological down-regulation of ARs and androgen-dependent growth in the rat corpora cavernosa.

Drugs for treatment of benign prostatic hyperplasia: affinity comparison at cloned alpha 1-adrenoceptor subtypes and in human prostate

1. We have previously shown that among alpha 1-adrenoceptor antagonists used or investigated for the treatment of benign prostatic hyperplasia, tamsulosin discriminates alpha 1-adrenoceptor subtypes in rat tissues whereas alfuzosin and naftopidil do not. We now expand these studies to additional drugs (doxazosin, terazosin) being used and/or investigated for this purpose, and have evaluated all of these drugs at cloned subtypes and in human prostate. 2. Competition binding studies were performed with [3H]-prazosin in membrane samples from rat spleen, kidney and cerebral cortex and human prostate and with cloned alpha 1-adrenoceptors expressed in COS cells. Doxazosin and terazosin did not discriminate alpha 1-adrenoceptor subtypes in rat kidney and cerebral cortex. In contrast, the subtypes present in the tissues were well discriminated by the alpha 1A-adrenoceptor-selective reference drug WB 4101. 3. Alfuzosin, doxazosin, naftopidil and terazosin did not discriminate cloned alpha 1-adrenoceptor subtypes transiently expressed in COS cells whereas tamsulosin and WB 4101 did. 4. In human prostate, alfuzosin, doxazosin, naftopidil and terazosin did not discriminate the alpha 1-adrenoceptor subtypes present in this tissue whereas tamsulosin and the alpha 1A-adrenoceptor-selective reference drugs WB 4101, phentolamine and 5-methylurapidil did. Based on data with the alpha 1A-adrenoceptor-selective drugs, human prostate contains alpha 1A- and alpha 1B-adrenoceptors in an approximate 70:30% ratio. 5. We conclude that tamsulosin, in common with WB 4101, but in contrast to alfuzosin, doxazosin, naftopidil, and terazosin is selective for alpha 1A-adrenoceptors which appear to dominate in the human prostate; the therapeutic relevance of this selectivity remains to be assessed in clinical studies.

Mechanisms involved in the spasmolytic effect of extracts from Sabal serrulata fruit on smooth muscle

1. The effects of two extracts from Sabal serrulata fruits [total lipidic (L) and saponifiable (S)] on smooth muscle contractions have been assayed. 2. Both extracts (0.1-1 mg/ml) relaxed the tonic contraction induced by norepinefrine (30 nM) on rat aorta [EC50, 0.53 +/- 0.05 mg/ml (L) and 0.5 +/- 0.04 mg/ml (S)] and by KCl (60 mM) on rat uterus. The Sabal extracts (0.3-1 mg/ml) also antagonized the dose-response curve of contractions induced by acetylcholine (0.1-100 microM) on urinary bladder. 3. dL-Propranolol (1 microM) but not the inactive (R)-(+)-propranolol(1 microM) potentiated the Sabal extracts relaxant effect by lowering the EC50 (0.35 +/- 0.2 vs 0.20 +/- 0.01 mg/ml for L and 0.43 +/- 0.02 vs 0.19 +/- 0.02 mg/ml, P < 0.01, for S extract). 4. Cycloheximide (10 micrograms/ml) antagonized the effect of extracts from Sabal. However, actinomycin D (5 micrograms/ml) significantly (P < or = 0.01) antagonized the effect of the total lipidic extract without modifying that of the saponifiable extract. 5. The relaxant effect of both extracts was not modified by the tyrosine kinase inhibitor genistein (10 microM) or the ornithine decarboxylase inhibitor alpha-difluoromethyl-ornithine (10 mM).

Tamsulosin, a selective alpha 1c-adrenoceptor antagonist: a randomized, controlled trial in patients with benign prostatic 'obstruction' (symptomatic BPH). The European Tamsulosin Study Group

OBJECTIVE

To evaluate the efficacy and safety of tamsulosin 0.4 mg once daily (as a modified-release formulation) compared with placebo in patients with benign prostatic enlargement, lower urinary tract symptoms and prostatic 'obstruction' (symptomatic benign prostatic hyperplasia [BPH]).

PATIENTS AND METHODS

Of 313 patients with symptomatic BPH enrolled in a 2-week placebo run-in period, 296 were subsequently randomized to receive either placebo (98 patients) or tamsulosin 0.4 mg once daily (198 patients) for 12 weeks. The primary variables assessed to determine efficacy were maximum urinary flow rate (Qmax) from free-flow measurements and the total Boyarsky symptom score.

RESULTS

Tamsulosin produced greater improvements in Qmax (1.4 mL/s, 13.1%) than did placebo (0.4 mL/s, 3.8%) (P = 0.028) and a greater decrease in total symptom score (3.4 points, 35.8% reduction) than did placebo (2.2 points, 23.7% reduction) (P = 0.002). Significantly more tamsulosin-treated patients (67%) than placebo-treated patients (44%) had a > or = 25% decrease in total symptom score after 12 weeks (P < 0.001). Treatment with tamsulosin for 12 weeks also produced significant improvements in average urinary flow rate (P = 0.040), irritative (P = 0.013) and obstructive (P = 0.014) symptom scores and symptoms of nocturia (P = 0.022) and hesitancy (P = 0.004). Tamsulosin was tolerated well by the patients. The incidence of adverse events emerging during treatment was comparable in the tamsulosin- and placebo-treated groups (34% and 24% respectively, P = 0.109), as was the incidence of cardiovascular-related adverse events (5% and 7% respectively; P = 0.596). There were no significant differences in changes in blood pressure or pulse rates between the tamsulosin- and placebo-treated groups.

CONCLUSION

Tamsulosin 0.4 mg once daily is safe, well tolerated and clinically effective in improving symptoms and urinary flow rate in patients with symptomatic BPH.