alpha-Blockade improves symptoms suggestive of bladder outlet obstruction but fails to relieve it

Pharmacokinetics and Bioequivalence Estimation of Two Formulations of Alfuzosin Extended-Release Tablets

Alfuzosin is a medication approved by the US Food and Drug Administration to treat benign prostatic hyperplasia symptoms. Bioequivalence studies are demanded by regulatory authorities to evaluate the expected in vivo biological similarity of 2 formulations of a medication. The aim of this study is to assess the bioavailability of the generic (test) and branded (reference) formulations of 10-mg alfuzosin extended-release tablets after oral administration to healthy adults under fed conditions. The study used a comparative randomized, single-dose, 2-way crossover open-label study design. Thirty-three participants were recruited and completed the clinical assessment. The pharmacokinetic parameters maximum plasma concentration (C_max ), area under the plasma concentration-time curve (AUC_0-t ), AUC extrapolated to infinity (AUC_0-∞ ), time to maximum concentration, and elimination half-life were estimated to prove bioequivalence. The confidence intervals for the log-transformed test/reference ratios for alfuzosin 110.7% (98.0-124.9) and 112.0% (101.9-123.1) for C_max and AUC_0-t respectively, which are within the allowed limits specified by the regulatory authorities (80-125% for C_max and AUC_0-t ). The test formulation can therefore be prescribed as an alternative to the reference for symptomatic treatment of benign prostatic hyperplasia.

Elevated hydrostatic pressure stimulates ATP release which mediates activation of the NLRP3 inflammasome via P2X4 in rat urothelial cells

Partial bladder outlet obstruction (pBOO) is a prevalent urological condition commonly accompanied by increased intravesical pressure, inflammation, and fibrosis. Studies have demonstrated that pBOO results in increased NLRP3 inflammasome and caspase-1 activation and that ATP is released from urothelial cells in response to elevated pressure. In the present study, we investigated the role of elevated pressure in triggering caspase-1 activation via purinergic receptors activation in urothelial cells. Rat urothelial cell line, MYP3 cells, was subjected to hydrostatic pressures of 15 cmH₂O for 60 min, or 40 cmH₂O for 1 min to simulate elevated storage and voiding pressure conditions, respectively. ATP concentration in the supernatant media and intracellular caspase-1 activity in cell lysates were measured. Pressure experiments were repeated in the presence of antagonists for purinergic receptors to determine the mechanism for pressure-induced caspase-1 activation. Exposure of MYP3 cells to both pressure conditions resulted in an increase in extracellular ATP levels and intracellular caspase-1 activity. Treatment with P2X₇ antagonist led to a decrease in pressure-induced ATP release by MYP3 cells, while P2X₄ antagonist had no effect but both antagonists inhibited pressure-induced caspase-1 activation. Moreover, when MYP3 cells were treated with extracellular ATP (500 µM), P2X₄ antagonist inhibited ATP-induced caspase-1 activation, but not P2X₇ antagonist. We concluded that pressure-induced extracellular ATP in urothelial cells is amplified by P2X₇ receptor activation and ATP-induced-ATP release. The amplified ATP signal then activates P2X₄ receptors, which mediate activation of the caspase-1 inflammatory response.

Benign Prostatic Obstruction Relief in Patients with Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Enlargement Undergoing Endoscopic Surgical Procedures or Therapy with Alpha-Blockers: A Review of Urodynamic Studies

Benign prostatic obstruction (BPO) contributes to the genesis of lower urinary tract symptoms as well as to pathologic remodeling of the lower and upper urinary tract in patients with benign prostate enlargement. Urodynamic studies demonstrate that both medical therapy with alpha-blockers (ABs) and endoscopic surgical procedures provide BPO relief. However, the magnitude of improvement is higher after surgery. Among ABs, silodosin is associated with the highest improvement of bladder outlet obstruction index (BOOI). A complex relationship exists between BOOI improvement and variations of both maximum urinary flow (Q _max) and detrusor pressure. When the reduction of BOOI is small, the improvement of Q _max is clinically irrelevant and the BOOI is mainly influenced by a decrease of detrusor pressure. In contrast, when the magnitude of BOOI reduction is robust, a meaningful improvement of both detrusor pressure and urinary flow is evident. When clustering ABs according to their receptor pharmacologic selectivity and urodynamic efficacy, three subgroups can be identified,with silodosin being the only member of a subgroup characterized by the highest levels of BOOI improvement and α-1A/α-1B receptor affinity ratio.

Simple Modification of the Bladder Outlet Obstruction Index for Better Prediction of Endoscopically-Proven Prostatic Obstruction: A Preliminary Study

Purpose

The bladder outlet obstruction index (BOOI), also known as the Abrams-Griffiths (AG) number, is the most widely used index for predicting BOO. However, the obstructed prostatic urethra determined by the BOOI is often inconsistent with endoscopically-proven obstruction. We assessed abdominal straining pattern as a novel parameter for improving the prediction of BOO.

Materials and Methods

We retrospectively reviewed the pressure-flow studies (PFS) and cystourethroscopy in 176 BPH/LUTS patients who were unresponsive to medical therapy. During PFS, some groups of patients tried to urinate with abdominal straining, which can increases intravesical pressure and underestimate BOOI theoretically. Accordingly, the modified BOOI was defined as (P_detQ_max+ΔP_abd)-2Q_max.

Results

Ultimately, 130 patients were eligible for the analysis. In PFS, ΔP_abd (P_abdQ_max-initial P_abd) was 11.81±13.04 cmH₂O, and it was 0–9 cmH₂O in 75 (57.7%), 10–19 cmH₂O in 23 (17.7%) and ≥20 cmH₂O in 32 (24.6%) patients. An endoscopically obstructed prostatic urethra in 92 patients was correctly determined in 47 patients (51.1%) by the original BOOI versus 72 patients (78.3%) based on the modified BOOI. Meanwhile, an “unobstructed” urethra according to the original BOOI was present in 11 patients (12.0%), whereas according to the modified BOOI, only 2 (2.1%) would be labeled as “unobstructed”. In receiver operating characteristic curves, the area under the curve was 0.906 using the modified BOOI number versus 0.849 in the original BOOI (p<0.05).

Conclusions

The change in abdominal pressure was correlated with endoscopically-proven obstruction. Our simple modification of the BOOI on the basis of this finding better predicted bladder outlet obstruction and, therefore, should be considered when evaluating BOO in patients with LUTS/BPH.

Neurological status predicts response to alpha-blockers in men with voiding dysfunction and Parkinson's disease

OBJECTIVES

To evaluate predictors of the response to doxazosin, a selective alpha-adrenoceptor antagonist, when used for the treatment of lower urinary tract symptoms in men with Parkinson's disease.

METHODS

In a prospective study, 33 consecutive men (mean age 59.2 ± 7.0 years) with Parkinson's disease and lower urinary tract symptoms were evaluated. Neurological dysfunction was assessed with the Unified Parkinson's Disease Rating Scale. Urological assessment was performed at baseline and after 12 weeks of treatment with 4 mg/day of extended-release doxazosin, including symptom evaluation with the International Continence Society male short-form questionnaire, an assessment of the impact of lower urinary tract symptoms on quality of life and urodynamics. Clinical and urodynamic predictors of response were specifically evaluated.

RESULTS

Compared with the score at baseline, the total International Continence Society male short-form score was reduced after doxazosin administration, from 17.4 ± 7.5 to 11.1 ± 6.9 (p<0.001). The impact of lower urinary tract symptoms on quality of life was also significantly reduced, from 1.8 ± 1.1 to 1.0 ± 1.0 (p<0.001) and the maximum urinary flow varied from 9.3 ± 4.4 to 11.2 ± 4.6 ml/s (p=0.025). The severity of neurological impairment was the only predictor of the clinical response. Additionally, patients with a Unified Parkinson's Disease Rating Scale score lower than 70 had a significantly higher chance of clinical improvement with doxazosin treatment than those with higher Unified Parkinson's Disease Rating Scale scores did (RR=3.10, 95% CI=[1.15 to 5.37], p=0.011).

CONCLUSIONS

Doxazosin resulted in the improvement of lower urinary tract symptoms and the maximum flow rate and was well tolerated in men with Parkinson's disease. The response to treatment is dependent on the severity of neurological disability.

Thermoanalytical investigation of terazosin hydrochloride

PURPOSE

Thermal analysis (TGA, DTG and DTA) and differential scanning calorimetry (DSC) have been used to study the thermal behavior of terazosin hydrochloride (TER).

METHODS

Thermogravimetric analysis (TGA/DTG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were used to determine the thermal behavior and purity of the used drug. Thermodynamic parameters such as activation energy (E*), enthalpy (∆H*), entropy (∆S*) and Gibbs free energy change of the decomposition (∆G*) were calculated using different kinetic models.

RESULTS

The purity of the used drug was determined by differential scanning calorimetry (99.97%) and specialized official method (99.85%) indicating to satisfactory values of the degree of purity. Thermal analysis technique gave satisfactory results to obtain quality control parameters such as melting point (273 ºC), water content (7.49%) and ash content (zero) in comparison to what were obtained using official method: (272 ºC), (8.0%) and (0.02%) for melting point, water content and ash content, respectively.

CONCLUSION

Thermal analysis justifies its application in quality control of pharmaceutical compounds due to its simplicity, sensitivity and low operational costs. DSC data indicated that the degree of purity of terazosin hydrochloride is similar to that found by official method.

Statistical approach for assessing the influence of calcium silicate and HPMC on the formulation of novel alfuzosin hydrochloride mucoadhesive-floating beads as gastroretentive drug delivery systems

Multiparticulate floating drug delivery systems have proven potential as controlled-release gastroretentive drug delivery systems that avoid the "all or none" gastric emptying nature of single-unit floating dosage forms. An objective of the presence investigation was to develop calcium silicate (CaSi)/calcium alginate (Ca-Alg)/hydroxypropyl methylcellulose (HPMC) mucoadhesive-floating beads that provide time- and site-specific drug release of alfuzosin hydrochloride (Alf). Beads were prepared by simultaneous internal and external gelation method utilizing 3(2) factorial design as an experimental design; with two main factors evaluated for their influence on the prepared beads; the concentration of CaSi as floating aid (X (1)) and the percentage of HPMC as viscosity enhancer and mucoadhesive polymer (X (2)), each of them was tested in three levels. Developed formulations were evaluated for yield, entrapment efficiency, particle size, surface topography, and buoyancy. Differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro drug release, as well as in vitro mucoadhesion using rat stomach mucosal membrane were also conducted. Percentage yield and entrapment efficiency ranged from 57.03% to 78.51% and from 49.78% to 83.26%, respectively. Statistical analysis using ANOVA proved that increasing the concentration of either CaSi or HPMC significantly increased the beads yield. Both CaSi and HPMC concentrations were found to significantly affect Alf release from the beads. Additionally, higher CaSi concentration significantly increased the beads diameter while HPMC concentration showed significant positive effect on the beads mucoadhesive properties. CaSi/Ca-Alg/HPMC beads represent simple floating-mucoadhesive gastroretentive system that could be useful in chronopharmacotherapy of benign prostatic hyperplasia.

Effect of tamsulosin versus prazosin on clinical and urodynamic parameters in women with voiding difficulty: a randomized clinical trial

Objective

To compare the effects of tamsulosin and prazosin on clinical and urodynamic parameters in women with voiding dysfunction.

Methods

Forty women aged 20–65 years with a clinical diagnosis of voiding dysfunction were blindly randomized to two equal groups for treatment with tamsulosin 0.4 mg or 1–2 mg of prazosin daily. Symptom assessment with the American Urological Association Symptom Score (AUASS) and urodynamic evaluation was performed initially and after three months of treatment. Patient satisfaction was evaluated and severe adverse drug effects recorded. Statistical analysis was carried out using the Student’s t-test and Mann–Whitney U test.

Results

Although AUASS improved in both groups, the rate of improvement was larger in the tamsulosin group. Urodynamic parameters improved but did not normalize in both groups. Adverse side effects from medication in the prazosin group were more common than in the tamsulosin group. Most of the patients in the tamsulosin group (80%) were satisfied with their treatment compared with those in the prazosin group (45%).

Conclusion

Tamsulosin and prazosin are both effective in palliating symptoms of women with voiding dysfunction and improving their urodynamic parameters. Tamsulosin may be the preferred drug to prescribe because of its more amenable side effect profile and greater patient satisfaction.

Urodynamic effects of silodosin, a new alpha 1A-adrenoceptor selective antagonist, for the treatment of benign prostatic hyperplasia

AIMS

To investigate urodynamically the effects of silodosin, a new alpha(1A)-adrenoceptor-selective antagonist, in the treatment of benign prostatic hyperplasia (BPH).

METHODS

Thirty six male patients with BPH (69.9 +/- 7.3 years), who were referred as candidates for surgery, were treated with silodosin (4 mg twice daily). The total International Prostate Symptom Score (IPSS) was 20.7 +/- 7.4, maximum flow rate (Q(max)) was 6.7 +/- 3.0 ml/sec, and prostate volume was 45.6 +/- 24.5 ml.

RESULTS

Total IPSS, storage and voiding symptom subscores and QOL score decreased significantly, and Q(max) increased significantly after 1-12 months of therapy (all P < 0.05). In urodynamic study (n = 29), maximum cystometric capacity increased significantly (P = 0.0027), and detrusor overactivity disappeared in 8 of 20 patients (40%) and improved (bladder capacity increased more than 50%) in 7 (35%) after the therapy. In pressure/flow studies (n = 27), the obstruction grade was improved in 15 patients (56%). Detrusor opening pressure, detrusor pressure at Q(max), bladder outlet obstruction index, and Schäfer's obstruction class decreased significantly after therapy (all P < 0.01). After 12 months, 16 patients (44%) are still on silodosin for 23.3 +/- 7.0 (range 12-36) months, and the improvements in IPSS and Q(max) were stable. Twenty patients withdrew because of insufficient effectiveness in 13 patients (12 patients underwent surgery), side effects in 3, and unknown reasons in 4.

CONCLUSION

Silodosin appears to improve detrusor overactivity and obstruction grade in patients with BPH. With silodosin treatment, LUTS could be managed effectively for more than a year in at least 44% of the patients.

The concept of neurogenic inflammation

Neurogenic inflammatory responses have recently been linked to both acute and chronic pathological conditions in the urinary tract. Neurogenic inflammation encompasses a series of vascular and non-vascular inflammatory responses, triggered by the activation of primary sensory neurons and the subsequent release of inflammatory neuropeptides, including substance P and calcitonin gene-related peptide. The reduction of neurogenic inflammatory responses may be key in the mode of action of the adrenergic alpha(1)-adrenoceptor antagonists used to treat lower urinary tract symptoms (LUTS). Indeed, the alpha(1)-adrenoceptor antagonist alfuzosin inhibits expression of the oncogene c-fos- a marker of nociceptive pathway activation - evoked by cyclophosphamide in rats. Capsaicin ameliorates urinary bladder symptoms through its stimulatory action on the transient receptor potential vanilloid 1 (TRPV1) calcium channel, resulting in desensitization of bladder sensory nerve terminals. Involvement of the TRP cation channel, subfamily A, member 1 (TRPA1) has also been reported in models of neurogenic inflammation and nociception promoted by the cyclophosphamide metabolite, acrolein. Blockade by alfuzosin demonstrates the beneficial effects of alpha(1)-adrenoceptor antagonists on neurogenic inflammation via the transient receptor potential family of ionic channels. Consequently, these drugs may have an important role in reducing LUTS.

Natural course of lower urinary tract symptoms following discontinuation of alpha-1-adrenergic blockers in patients with benign prostatic hyperplasia

OBJECTIVE

alpha1-adrenergic blockers (alphab) remain the first-line therapy in men with lower urinary tract symptoms (LUTS). The current published work advocates continued use of alphab for their effect to be maintained. However, some patients decide to discontinue use of the medication after their symptoms are relieved and can keep good conditions. In this study, we investigated the natural course of LUTS after the discontinuation of successful treatment of alphab.

METHODS

Among 75 patients with LUTS who stopped alphab medication once their symptoms improved, 60 patients (age, 50-87 years; median, 70) who could be followed for at least 12 months after discontinuation of alphab were analyzed in this study. Evaluations included a clinical determination of the International Prostate Symptom Score (IPSS), peak flow rate (Qmax) and postvoid residual urine volume (PVR). Upon patient request or in cases of PVR more than 100 mL, administration of alphab was resumed.

RESULTS

Eighteen out of the 60 patients (30%) asked for re-treatment within 12 months after discontinuation (re-treatment group). The other 42 patents were able to maintain good condition without medication (discontinuation group). The IPSS was 15.9, 8.7, 10.1, 10.2, 9.7, 8.8 and 9.0, on the first visit, just before discontinuation, and 1, 3, 6, 9 and 12 months after stopping treatment among the discontinuation group, respectively. Similarly, Qmax was 10.6, 14.8, 14.2, 14.3, 14.7, 13.2 and 13.6 mL/ s, respectively. Treatment periods, prostatic volume and peak flow rates just before discontinuation of medication differed significantly between the re-treatment and discontinuation group.

CONCLUSIONS

In spite of the short follow-up periods, these results suggest that selected patients with relatively small prostatic volume and good flow rates after therapy can discontinue alphab medication after their symptoms improve.

alpha-Blockers improve chronic ischaemia of the lower urinary tract in patients with lower urinary tract symptoms

OBJECTIVE

To investigate whether a mechanism of action of alpha-blockers on lower urinary tract symptoms (LUTS) involves improved perfusion of the LUT.

PATIENTS, SUBJECTS AND METHODS

The accuracy of perfusion measurements using transrectal colour Doppler ultrasound (TRCDUS) and colour pixel density (CPD) was initially confirmed in a porcine model. Following this confirmation, measurements were taken from four healthy male volunteers and 19 patients with LUTS. The urinary bladder was filled slowly (50 mL/min) with 0.2 m KCl, which resembles the osmolarity of concentrated urine, and evaluated by cystometry. In parallel, TRCDUS and measurement of the CPD of the LUT were performed. The patients with LUTS were then treated with daily alpha-blocker (0.4 mg tamsulosin) for 5 weeks and urodynamic variables as well as perfusion were evaluated again.

RESULTS

In the healthy men, perfusion of the LUT increased considerably (157%) during filling of the bladder to a mean (sd) maximum cystometric capacity (C(max)) of 481 (28.9) mL. All the patients with LUTS had a reduced mean C(max) during filling with KCl at 322.4 (58.5) mL. The mean CPD in the urinary bladder and the prostate were only increased by 58.4% during filling with KCl. After alpha-blocker therapy the mean C(max) during filling with KCl rose to 382.5 (42.9) mL; furthermore, perfusion of the LUT measured by CPD was significantly increased (132.8%).

CONCLUSIONS

The present data strongly suggest that LUTS are associated with chronic ischaemia of the prostate and urinary bladder. alpha-blockers increase perfusion in the LUT and C(max). These results might explain the therapeutic effects of alpha-blockers on LUTS.

The Influence of Alpha1-Adrenoreceptors on Neuropeptide Release from Primary Sensory Neurons of the Lower Urinary Tract

OBJECTIVES

Adrenergic alpha(1)-receptors agonists and antagonists have been reported to increase and reduce, respectively, neurogenic inflammatory responses mediated by capsaicin-sensitive sensory neurons. However, the precise role and localization of the alpha(1)-adrenoceptors involved in these effects are not known.

METHODS

We have studied in the rat whether functional alpha(1)-adrenoreceptors are expressed in primary sensory neurons, and whether they regulate neurogenic inflammation and nociceptive responses in the urinary bladder.

RESULTS

The alpha(1)-adrenoreceptor agonist phenylephrine (1 micromol/l) (1) mobilized intracellular Ca(2+) in cultured lumbar and sacral dorsal root ganglia neurons, (2) caused the release of substance P (SP) from terminals of capsaicin-sensitive sensory neurons from the lumbar enlargement of the dorsal spinal cord and urinary bladder, and (3) increased plasma protein extravasation in the urinary bladder. All these effects were abolished by the alpha(1)-adrenoceptor antagonist alfuzosin (10 micromol/l). Furthermore, alfuzosin (30 microg/kg, i.v.) partially, but significantly, inhibited cyclophosphamide-induced plasma protein extravasation in the rat urinary bladder. Phenylephrine-induced Ca(2+) mobilization in cultured dorsal root ganglia neurons was exaggerated by pretreating the rats in vivo with cyclophosphamide. Finally, cyclophosphamide increased c-fos expression in the rat lumbar spinal cord. Also these in vitro and in vivo effects were inhibited by pretreatment with alfuzosin.

CONCLUSIONS

Alpha(1)-adrenoceptors are functionally expressed by capsaicin-sensitive, nociceptive, primary sensory neurons of the rat urinary tract, and their activation may contribute to signal irritative and nociceptive responses arising from the urinary tract. It is possible that, at least, part of the beneficial effects of alpha(1)-adrenoceptor antagonists in the amelioration of storage symptoms in the lower urinary tract derives from their inhibitory effect on neurogenic inflammatory responses.

Prediction of alpha1-adrenoceptor occupancy in the human prostate from plasma concentrations of silodosin, tamsulosin and terazosin to treat urinary obstruction in benign prostatic hyperplasia

Alpha1-adrenoceptor antagonists are clinically useful for the improvement of urinary obstruction due to benign prostatic hyperplasia (BPH), and their therapeutic effects are mediated through the blockade of prostatic alpha(1)-adrenoceptors. The present study was undertaken to predict the magnitude and duration of alpha(1)-adrenoceptor occupancy in the human prostate after oral alpha(1)-adrenoceptor antagonists. Prostatic alpha(1)-adrenoceptor-binding parameters of silodosin were estimated by measuring specific [(3)H]prazosin binding in rat prostate after oral administration of this drug. The plasma concentration of silodosin after oral administration in rats and healthy volunteers was measured using a high-performance liquid chromatographic method. The alpha(1)-adrenoceptor-binding affinities (K(i)) of silodosin, tamsulosin, and terazosin in the human prostate and plasma concentrations of tamsulosin and terazosin were obtained from the literature. Using the alpha(1)-adrenoceptor binding parameters of silodosin in rat prostate, alpha(1)-adrenoceptor occupancy in the human prostate was estimated to be around 60-70% at 1-6 h after oral administration of silodosin at doses of 3.0, 8.1, and 16.1 micromol. Thereafter, the receptor occupancy was periodically decreased, to 24% (8.1 micromol) and 54% (16.1 micromol) 24 h later. A similar magnitude and time course of alpha(1)-adrenoceptor occupancy by silodosin in the human prostate were estimated using alpha(1)-adrenoceptor-binding affinities (K(i)) in the human prostate. Despite about two orders of differences in the plasma unbound concentrations after clinically effective oral dosages of silodosin, tamsulosin, and terazosin, there was a comparable magnitude of prostatic alpha(1)-adrenoceptor occupancy by these drugs. In conclusion, the prediction of alpha(1)-adrenoceptor occupancy in the human prostate by alpha(1)-adrenoceptor antagonists may provide the rationale for the optimum dosage regimen of these drugs in the therapy of BPH.

Pharmacology of α1-adrenoceptor antagonists in the lower urinary tract and central nervous system

The main use of alpha(1)-adrenoceptor (AR) antagonists in urology has been to treat lower urinary tract symptoms (LUTS) in men with benign prostatic obstruction (BPO). The beneficial effects of these agents are primarily assumed to be because of relaxation of prostatic and urethral smooth muscle. The weak correlation between LUTS and prostatic enlargement, outflow obstruction, or both, however, has refocused interest on the role of extraprostatic alpha-ARs in the pathogenesis of LUTS and their treatment. The alpha(1)-ARs present in the bladder, urethra, vas deferens, peripheral ganglia, nerve terminals, and in the central nervous system could all potentially influence LUTS and, when the receptors are blocked, contribute to both the therapeutic and adverse effects of alpha(1)-AR antagonists. The relevance of alpha(1)-AR-subtype selectivity on the clinical usefulness of existing drug therapies has not been firmly established but it seems that blockade of both alpha(1A/L)- and alpha(1D)-ARs is necessary for the optimum balance between clinical efficacy and adverse effects.

An evaluation of the economic costs and patient-related consequences of treatments for benign prostatic hyperplasia

OBJECTIVE

To compare the costs and effectiveness of treatments for benign prostatic hyperplasia (BPH), including watchful waiting, pharmaceuticals (alpha-blockers, 5-alpha-reductase inhibitors, combined therapy), transurethral microwave thermotherapy (TUMT), and transurethral resection of the prostate (TURP).

PATIENTS AND METHODS

This study used a Markov model over a 20-year period and the societal perspective to evaluate the costs of treatment alternatives for BPH. Markov states include urinary symptom improvement, symptom improvement with adverse effects, or no urinary symptom improvement. For the analysis, patients could remain on their initial treatment, change to a different treatment, have treatment failure that required TURP, or die (all-cause mortality). We used published data for outcomes, including systematic reviews when possible. Costs were estimated using a managed-care claims database and Medicare fee schedules. Costs and effectiveness outcomes were discounted at 3%/year where appropriate. Men (aged > or = 45 years) with moderate-to-severe lower urinary tract symptoms and uncomplicated BPH were included in the analysis, and results were stratified by age. Outcomes include costs, disease progression, surgery, hospitalization, and catheterization time.

RESULTS

What is the 'best' treatment depends on the value that an individual and society place on costs and consequences. alpha-Blockers are less expensive than the alternatives, and are effective at relieving patient-reported symptoms. Unfortunately, they have little effect on clinical outcomes and have the highest BPH progression rate. Other treatments have lower disease progression and better clinical outcomes, but are more expensive and entail more invasive treatments, and/or more uncertainty.

CONCLUSIONS

Treatment decisions are made using a variety of information, including the cost and consequences of treatment. The best treatment depends on the patient's preference and the outcome considered most important. alpha-Blockers are very effective at treating urinary symptoms but do not improve clinical outcomes, including disease progression, relative to other treatments. TURP remains the 'gold standard' for surgical procedures. The desire to avoid TURP or the 2 weeks of catheterization associated with TUMT might affect a patient's treatment decision when symptoms are severe. Therefore, more information about patient preferences and risk aversion is needed to inform treatment decision-making for BPH.

Management of Benign Prostate Hyperplasia: An Overview of α-Adrenergic Antagonist

Benign prostate hyperplasia (BPH) is common among above 50 years age group, interfere with normal activities of lower urinary tract function and reduce the sense of well being. It can also be progressive, with a lost of urinary retention, bladder infection, bladder calculus and renal failure. Although many men with mild to moderate symptoms to well without therapy, others have gradually increasing symptoms and require medical therapy or surgery. BPH is the non-malignant, uncontrolled growth of cells in the prostate gland. This cell growth usually occurs in the tissue that surrounds the urethra as it passes through the prostate gland to the bladder. As BPH progresses, the gland constricts the urethra and obstructs the urine outflow. The bladder no longer empties completely, creating an environment in which infections, bladder stones, and chronic prostatities may develop. If left untreated, chronic obstruction can lead to the back up of urine into the ureters and compromise kidney function. In hyperplastic prostate tissue, the prostate capsule, and the bladder neck are blocked, by using alpha-adrenergic antagonist drugs; the smooth muscle tone of these structures is decreased. As a result, resistance to urinary flow through the bladder neck and the prostatic urethra decreases and urinary flow increases. A variety of alpha-adrenergic antagonists with distinct properties have been investigated as possible treatments for benign prostate hyperplasia.

Efficacy of the combination of an α1-blocker with an anticholinergic agent in the treatment of lower urinary tract symptoms associated with bladder outlet obstruction

The combination of an alpha1-blocker with an anticholinergic is a new and promising therapeutic approach for bladder outlet obstruction and detrusor overactivity. Both placebo-controlled and comparative studies have demonstrated that the addition of an anticholinergic in the conventional treatment of patients with bladder outlet obstruction is safe, as the likelihood of acute urinary retention is low. Although the pathophysiology of detrusor overactivity is unknown and most probably multifactorial, it is not expected that the voiding phase is influenced by regular doses of anticholinergics, although high doses may affect detrusor contraction. However, safety issues must be studied further. The combination of tamsulosin with propiverine or tolterodine, and of doxasosin with tolterodine has been shown to cause a significant improvement of lower urinary tract symptoms when compared with alpha1-blocker monotherapy. Indisputably, the existing literature provides clear evidence that the combination of an alpha1-blocker with an anticholinergic extends physicians ability to manage lower urinary tract symptoms caused by bladder outlet obstruction and overactive bladder syndrome.

Effects of TAK-802, a novel acetylcholinesterase inhibitor, and tamsulosin, an alpha1-adrenoceptor antagonist, and their synergistic effects on the urodynamic characteristics in a guinea-pig model of functional bladder outlet obstruction

OBJECTIVE

To investigate the effects of TAK-802, a potent acetylcholinesterase inhibitor, and tamsulosin, an alpha1-adrenoceptor antagonist, and their concomitant administration on the urodynamic characteristics in a guinea-pig model of functional bladder outlet obstruction.

MATERIALS AND METHODS

Cystometry was performed in urethane-anaesthetized guinea pigs, and various urodynamic variables, including the maximum flow rate (Qmax), voiding efficiency, maximum intravesical pressure (Pvesmax) and intravesical pressure at Qmax (PvesQmax), were measured before and after administration of the drugs in combination and alone.

RESULTS

Continuous intravenous infusion of phenylephrine, an alpha1-adrenoceptor agonist (1-6 microg/animal/min), dose-dependently decreased the Qmax and voiding efficiency, and increased the Pvesmax and PvesQmax, possibly by constricting urethral smooth muscle. In this functional urethral constriction model, both TAK-802 at 1 and 10 microg/kg and tamsulosin at 3 and 10 microg/kg (intravenously) caused increasing effects on the Qmax and voiding efficiency. The effects were more apparent with combined exposure. Although the Pvesmax was dose-dependently increased by TAK-802 alone, the effects were completely abolished by concomitant treatment with tamsulosin.

CONCLUSION

These results suggest that TAK-802 and tamsulosin have synergistic effects in increasing the Qmax and voiding efficiency, and TAK-802 does not inhibit the decreasing effect of tamsulosin on urethral resistance. That TAK-802 increased Pves when administered alone implies that monotherapy using an acetylcholinesterase inhibitor should be withheld in patients with voiding dysfunction caused by obvious bladder outlet obstruction with benign prostatic hyperplasia, to avoid disorders of the upper urinary tracts, and it should be used with an alpha1-adrenoceptor antagonist. Whether TAK-802 combined with an alpha1-adrenoceptor antagonist confers additional clinical benefit is not yet known.

Change in parameters before and after alpha-1-blocker therapy for men with lower urinary tract symptoms using color doppler ultrasound urodynamics: possible application for prediction of clinical outcome

INTRODUCTION

We previously developed a noninvasive video urodynamic study using color Doppler ultrasonography. We sought the best flow velocity-related parameter which would allow prediction of an improvement in lower urinary tract symptoms (LUTS) after alpha 1-blocker treatment.

METHODS

Twenty-two men with benign prostatic hyperplasia who were treated with a nonselective alpha 1-blocker (urapidil) were included. Subjective symptoms were evaluated using the International Prostate Symptom Score (IPSS) before and after alpha 1-blocker treatment. We measured the flow velocities using a transperineal ultrasound technique in the distal prostatic urethra just proximal to the external urethral sphincter (V1) and in the sphincteric urethra (V2), and used them to obtain the velocity ratio (VR=V1/V2). The corresponding functional cross-sectional areas of the urethra at these two sites (A1 and A2) were calculated as Q(max)/V. All these parameters obtained by the velocity-flow urodynamics were compared before treatment and after 4 weeks.

RESULTS

After treatment, V1 and VR were decreased, and A1 was increased. V2 correlated best with the change in IPSS before and after alpha 1-blocker therapy, with Spearman's rho of 0.584. All men with V2 exceeding 50 cm/s did not show an improvement in the LUTS.

CONCLUSIONS

The maximum flow velocity at the sphincteric urethra (V2) can predict the subjective outcome of alpha 1-blocker treatment. The velocity-flow parameters changed after alpha 1-blocker treatment. We confirmed that the transperineal ultrasound urodynamic study is not only noninvasive but also informative.

Long-term treatment outcome of tamsulosin for benign prostatic hyperplasia

BACKGROUND

The present study assessed the long-term efficacy (>12 months) of tamsulosin in 123 patients with lower urinary tract symptoms caused by benign prostatic hyperplasia (BPH).

METHODS

The patients received a starting dose of tamsulosin of 0.2 mg/day, with a further titration up to 0.4 mg/day until symptom relief. Subjective and objective clinical variables were assessed using the international prostate symptom score (IPSS), IPSS quality of life (QoL) score, BPH impact index score, peak urinary flow rate (Q(max)) and postvoid residual urine volume.

RESULTS

Except for Q(max), all clinical variables showed significant sustained improvements from baseline throughout the study period (median follow up, 43 months). Thirty patients (24.4%) withdrew because of surgical interventions. The Cox proportional hazards model showed that a baseline IPSS total score >or=15 (HR [hazard ratio] 2.13; 95% CI 1.04-4.34) was predictive of failure for tamsulosin therapy. Furthermore, during the first 12 months, a lowest IPSS total score >or=13 (HR 2.34; 95% CI 1.12-4.89), a lowest IPSS QoL score >or=3 (HR 4.16; 95% CI 1.26-13.68), and a lowest BPH impact index score >or=4 (HR 3.54; 95% CI 1.62-7.75) were also predictive of failure for tamsulosin therapy.

CONCLUSIONS

Tamsulosin treatment of BPH patients for more than 12 months showed a sustained, stable efficacy. Patients without short-term effects were prone to withdraw from tamsulosin therapy, but so did patients with a high baseline IPSS total score, even if therapy was effective for at least 12 months.

Formulary Conversion from Doxazosin to Terazosin for the Treatment of Benign Prostatic Hyperplasia in a Small Veterans Hospital

Doxazosin and terazosin are alpha1-adrenergic blockers that are commonly used for the treatment of benign prostatic hyperplasia (BPH). Doxazosin or terazosin can both be given once daily because of their relatively long elimination half-lives (approximately 22 hours for doxazosin, and 9 to 12 hours for terazosin). Common adverse effects of these two drugs include orthostatic hypotension and syncope, especially with the first dose or initial therapy. Based on cost and equivalent efficacy between the two alpha1 blockers, terazosin was selected as the formulary agent for a long-acting alpha1-adrenergic blocker in the Cheyenne Veterans Administrative Medical Center (Cheyenne VAMC). The study was conducted with 12 patients with symptomatic BPH to evaluate the appropriate doses of terazosin when patients taking doxazosin are switched for the treatment of BPH. The results indicated that the two alpha1 blockers provided similar control of BPH symptoms. The mean differences of symptom scores obtained after the two treatment regimens (doxazosin vs terazosin) were not significant (mean ± S.D. 11.17 ± 7.93 vs 9.67 ± 7.48, 95% confidence interval [CI] of the mean difference −1.18 ± 4.18; P = 0.243). No dosage titration was needed at the time of initial switching from doxazosin to terazosin. Additionally, it appears that terazosin doses of 1, 2, 5, 7, and 10 mg can be used initially when doxazosin (at corresponding doses of 1, 2, 4, 6, and 8 mg, respectively) is converted to terazosin for the management of BPH.

Overactive bladder and men: Indications for anticholinergics

Similar to bladder outlet obstruction (BOO), overactive bladder (OAB) symptoms are very common and increase in prevalence as men age. Whether or not OAB symptoms are thought to be secondary to BOO, the goal of treatment of symptoms should result in an improved quality of life and ultimately prevent clinical deterioration. A common dilemma when treating men with obstruction and OAB is the risk of acute urinary retention or morbidities related to increasing postvoid residuals. In this article, the relationship of OAB to BOO is examined and the role of urodynamics and data on the use of anticholinergics in men with OAB and obstruction are reviewed. An algorithm for managing men with OAB also is proposed. In men with OAB without evidence of obstruction (including OAB after treatment for BOO), first-line medical therapy with anticholinergics is indicated. However, in men with OAB and concomitant BOO, nomogram has been developed to assist in the management of patients at risk for urinary retention. Men with significant obstruction should be appropriately treated to decrease bladder outlet resistance before adding anticholinergics for the treatment of OAB.

Selective and sustained occupancy of prostatic alpha1-adrenoceptors by oral administration of KMD-3213 and its plasma concentration in rats

This study examined the ex-vivo occupancy by KMD-3213 of alpha1-adrenoceptors in the prostate and other tissues of rats in terms of tissue selectivity and duration of occupancy in relation to plasma concentration. Oral administration of KMD-3213 (0.2-20.2 micromol kg(-1), 0.5 h) dose-dependently decreased [3H]prazosin binding sites (Bmax) in the prostate (42-74%) and submaxillary gland (54-88%) compared with the control value. In contrast, there was only a slight change in the Bmax values in the spleen and cerebral cortex of KMD-3213-treated rats. The alpha1-adrenoceptor occupancy in the prostate and submaxillary gland was increased, with plasma free concentration of KMD-3213 at 0.5 h after oral administration of KMD-3213 (0.6-20.2 micromol kg(-1)). The receptor occupancy in these tissues was much greater than that in the spleen, heart or cerebral cortex. After oral administration of KMD-3213 (6.1 micromol kg(-1)), the alpha1-adrenoceptor occupancy in the prostate and submaxillary gland occurred rapidly, in parallel with the rise in the plasma concentration of the drug, and it lasted for at least 24 h, despite a remarkable decrease in the plasma concentration. It is concluded that KMD-3213 may produce fairly selective and sustained occupancy of alpha1-adrenoceptors in the prostate, a target organ for treatment of bladder outlet obstruction in patients with benign prostatic hyperplasia.

Tamsulosin: current clinical experience

During the past decade, our understanding of the epidemiology and natural history of benign prostatic hyperplasia (BPH) has improved considerably. Population-based studies confirm that lower urinary tract symptoms (LUTS) are very common among aging men. These studies have confirmed that men with moderate-to-severe symptoms have 4 to 6 times more trouble and interference with activities of daily living and twice the level of worry as those with mild symptoms. The realization by patients and their physicians that most men >50 years of age will develop LUTS, has resulted in increased awareness of pharmacologic agents, principally alpha-adrenergic antagonists, as a first line of therapy for this condition. Alpha blockers were introduced >30 years ago to treat LUTS and today are the mainstay in pharmacologic therapy. Among the alpha blockers, tamsulosin more selectively targets the alpha(1A)-adrenergic receptor subtype and is as effective as conventional alpha(1) blockers in treating LUTS caused by BPH. Its subselectivity and pharmacodynamic properties may provide advantages in safety, tolerability, and administration compared with other alpha blockers, such as terazosin and doxazosin. Unlike other alpha blockers, tamsulosin does not require titration to be efficacious. Because of its rapid onset of action and lack of clinically significant effect on blood pressure in normotensive and hypertensive patients, a therapeutic dose is delivered at the onset of treatment. Studies have documented that tamsulosin produces rapid improvements in LUTS and peak urinary flow rates, and these responses have been found to be durable.

Comparison of prazosin, terazosin and tamsulosin: functional and binding studies in isolated prostatic and vascular human tissues

BACKGROUND

Terazosin and tamsulosin are drugs currently used in the treatment of benign prostatic hypertrophy (BPH). The potency of these two alpha(1) receptor antagonists and that of prazosin to inhibit contractions induced by noradrenaline and the binding of [(3)H]-prazosin in human prostate and four different human arterial and venous vessels (saphenous and umbilical veins, renal and mesenteric arteries) was studied.

METHODS

By bioassay and binding studies, we examined the receptor affinities of different alpha(1) receptor antagonists in different human tissues.

RESULTS

pKb of terazosin, tamsulosin, and prazosin obtained in the prostatic tissues (8.15, 9.64, and 8.59, respectively) were not different from those obtained in the umbilical veins (8.07, 9.56, and 8.30, respectively), in the mesenteric artery (8.27, 10.29, and 9.01, respectively), renal artery (8.35, 10.13, and 8.76, respectively) and saphenous vein (7.8, 10.3, and 9.32, respectively). IC(50) (nM) of prazosin, terazosin, and tamsulosin obtained from binding studies in membrane preparations from prostate tissue were similar to those from umbilical veins, saphenous vein, and renal artery.

CONCLUSIONS

All of the evaluated drugs showed similar selectivity for prostatic vs. vascular tissues. Thus, different clinical profiles of the present drugs should not result from their differential affinity for prostatic versus vascular alpha(1)-adrenoceptors.