Use of an alpha 1-blocker, YM617, in the treatment of benign prostatic hypertrophy. YM617 Clinical Study Group

Determination of tamsulosin in plasma of healthy Chinese male subjects by a novel and simple LC-MS/MS method and its application to pharmacokinetic studies

Tamsulosin, the first highly selective α1-adrenoceptor antagonist, is widely used for urination disorders caused by benign prostatic hyperplasia (BPH). The pharmacokinetics and safety of 0.2 mg tamsulosin hydrochloride sustained-release capsules were evaluated in 60 healthy Chinese male subjects under fasting and fed conditions in this study. A simple, sensitive, and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of tamsulosin in human plasma, which has been applied to pharmacokinetic study. The analyte and internal standard (tamsulosin-d5) were extracted by protein precipitation, and separated on a ZORBAX Eclipse XDB-C18 column (4.6 × 50 mm,1.8 µm; Agilent Tech) using a gradient elution with mobile phases methanol and 5 mM ammonium acetate. The linear range was 0.05-15.0 ng/mL. It showed good selectivity in normal, hyperlipidemic, and hemolyzed blank matrices. The CV (%) of intra-batch precision was <4.4% and the RE (%) of accuracy was in the range of -5.0%-6.7%; the CV (%) of inter-batch precision was <-5.8% and the RE (%) of accuracy was in the range of 1.2%-4.0%. The mean extraction recovery for the analyte was 102.1 ± 3.75% and for the IS was 102.2 ± 2.00%. Two formulations were considered bioequivalent under fasting and fed conditions, and the 90% confidence intervals for the geometric mean test/reference ratios were within the predetermined range of 80%-125%. A single oral dose of 0.2 mg tamsulosin hydrochloride sustained-release capsule was well-tolerated throughout the clinical trial, and no > Grade 1 adverse events (AEs) and serious AEs occurred during the trial.

Efficacy and safety of tamsulosin 0.4 mg single pills for treatment of Asian patients with symptomatic benign prostatic hyperplasia with lower urinary tract symptoms: a randomized, double-blind, phase 3 trial

OBJECTIVE

To verify the efficacy and safety of tamsulosin 0.4 mg and tamsulosin 0.2 mg compared with those of placebo in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH).

METHODS

A total of 494 patients from multiple centers participated in this double-blind, randomized, phase 3 trial. Eligible patients were randomly assigned to the tamsulosin 0.4 mg group, tamsulosin 0.2 mg group or placebo group. The International Prostate Symptom Score (IPSS), maximum flow rate (Qmax), post-void residual (PVR) urine volume, blood pressure, heart rate and adverse events were compared among the three groups at 4, 8 and 12 weeks.

RESULTS

A total of 494 BPH patients were analyzed. There were no differences in the baseline characteristics among the three groups. After 12 weeks of treatment, total IPSS was improved in the 0.2 mg and 0.4 mg tamsulosin groups; however, the extent of improvement was greater in the 0.4 mg group than in the 0.2 mg group (0.4 mg: -9.59 vs. 0.2 mg: -5.61; least-squares mean difference [95% confidence interval]: -3.95 [-5.01, -2.89], p < .0001). In addition, in the patients with severe symptoms (IPSS ≥20), total IPSS was improved the most in the 0.4 mg group (-11.27 ± 5.00, p < .0001). Qmax and PVR were improved in the 0.4 mg and 0.2 mg groups; however, the differences were not statistically significant between treatment groups. No patients experienced any serious adverse effects in any of the three groups.

CONCLUSIONS

Tamsulosin 0.4 mg and 0.2 mg appear to be superior to placebo treatment, and tamsulosin 0.4 mg is more effective than 0.2 mg in terms of total IPSS improvement. Tamsulosin 0.4 mg has favorable efficacy and tolerability in Asian men with symptomatic BPH. ClinicalTrials.gov Identifier: NCT02390882.

Evidence Is Enough?: A Systematic Review and Network Meta-Analysis of the Efficacy of Tamsulosin 0.2 mg and Tamsulosin 0.4 mg as an Initial Therapeutic Dose in Asian Benign Prostatic Hyperplasia Patients

Purpose

We compared the efficacy of tamsulosin between 0.2 mg and 0.4 mg in Asian prostatic hyperplasia (BPH) patients using network meta-analysis due to lack of studies with direct comparison.

Methods

The literature search was conducted using the MEDLINE, Embase, and Cochrane Library. Keywords used were “BPH,” “tamsulosin,” “placebo.” Experimental groups were defined as tamsulosin 0.2 mg (Tam 0.2) and 0.4 mg (Tam 0.4) and common control group was defined as placebo for indirect treatment comparison. Mixed treatment comparison was performed including one direct comparison study.

Results

Seven studies met the eligible criteria. Indirect treatment comparison revealed that total International Prostate Symptoms Score (IPSS) and quality of life score of IPSS were not significantly different in Tam 0.2 and Tam 0.4 (P>0.05). There was no significant difference of maximal flow rate and postvoid residual urine volume in Tam 0.2 and Tam 0.4 (P>0.05). Mixed treatment comparison including one direct comparison study showed inconsistency (P<0.001). Therefore, analysis using direct treatment comparison effect sizes of Tam 0.2 vs. placebo and Tam 0.4 vs. placebo was done and there was no significant difference.

Conclusions

Network meta-analysis showed no difference of efficacy between tamsulosin 0.2 mg and 0.4 mg and the evidence of tamsulosin 0.4 mg as initial dose for Asian BPH patient seems to be insufficient. Therefore, initial dose of tamsulosin for Asian BPH patient should be 0.2 mg.

Rate and associated factors of solifenacin add-on after tamsulosin monotherapy in men with voiding and storage lower urinary tract symptoms

AIM

To explore the rate of add-on therapy with solifenacin in men with voiding and storage lower urinary tract symptoms (LUTS) after tamsulosin monotherapy and to explore predictive factors for starting solifenacin add-on therapy.

METHODS

Men aged ≥ 45 years with IPSS ≥ 12 and symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 2/24 h) were enrolled to receive tamsulosin 0.2 mg once daily. After 4 weeks, men with residual symptoms of OAB and reported 'dissatisfied' or 'a little satisfied' were received solifenacin 5 mg in combination with tamsulosin monotherapy. Subjects completed an IPSS, a Quality of life (QoL) index, OAB V8, and an International Consultation of Incontinence Questionnaire (ICIQ)-Male LUTS, and patient perception of bladder condition (PPBC) at baseline and week 4.

RESULTS

Of a total of 305 patients, 254 patients completed 4 weeks of tamsulosin treatment. For 176 patients, solifenacin was added (69.3%). Significant predictive factors of solifenacin add-on therapy included long LUTS duration, high IPSS, number of micturitions per 24 h, more urgency episodes, high urgency severity score in a voiding diary and high OAB V8 score. Based on multivariable analysis, potential predictive factors of solifenacin add-on therapy included long LUTS duration (OR = 1.008, 95% CI: 1.001-1.014), high serum PSA (OR = 1.543, 95% CI: 1.136-2.095) and small prostate size (OR = 0.970, 95% CI: 0.947-0.994) (p < 0.05). IPSS, daytime micturitions and urgency episodes, OAB V8 scores, ICIQ and PPBC were improved after tamsulosin monotherapy.

CONCLUSIONS

Two thirds of men with voiding and storage LUTS needed to add anticholinergics after 4 weeks of tamsulosin monotherapy. Patients with longer lasting symptoms and storage symptoms with small prostate volume may require the anticholinergic add-on.

Persistence with solifenacin add-on therapy in men with benign prostate obstruction and residual symptoms of overactive bladder after tamsulosin monotherapy

AIMS

In spite of the reported efficacy and safety of antimuscarinics in men with OAB (overactive bladder) and BPO (benign prostatic obstruction), many patients do not persist with the treatment. We aimed to evaluate persistence and the reasons for the discontinuation of solifenacin add-on therapy in men with residual symptoms of OAB after tamsulosin monotherapy for BPO in a real clinical environment.

METHODS

Men aged ≥ 45 years with IPSS ≥ 12 and symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 2/24 h) were prescribed tamsulosin 0.2 mg. After 4 weeks, men who had residual symptoms of OAB (OAB-V8 ≥ 8, micturition ≥ 8/24 h, urgency ≥ 1/24 h) and reported that they were 'dissatisfied' or 'a little satisfied' with the therapy were enrolled and prescribed solifenacin 5 mg in combination with tamsulosin. After 52 weeks, persistence and the reasons for the discontinuation of solifenacin were evaluated. Factors related to persistence were analysed.

RESULTS

Of the 305 men who had been treated with tamsulosin, 176 were prescribed solifenacin. After 52 weeks, 44 (25%) remained on solifenacin therapy. Of the 132 who discontinued solifenacin, 85 were evaluated on the reason for discontinuation. The three most common reasons for discontinuation were adverse events (AEs) (35%), lack of efficacy (33%), and improvement in symptoms (16%). The aggravation of voiding symptoms was the most common AE leading to discontinuation. Retention was observed in 11 men. None of the demographical or clinical characteristics were significantly related to persistence.

CONCLUSIONS

Only 25% men with OAB and BPO remained on antimuscarinic add-on therapy after 1 year, mostly because of AEs and lack of efficacy. Realistic data should be added to what is already known about antimuscarinic treatment in men by including patients who were excluded or who dropped out of well-designed clinical trials.

Tadalafil once daily for lower urinary tract symptoms suggestive of benign prostatic hyperplasia: a randomized placebo- and tamsulosin-controlled 12-week study in Asian men

OBJECTIVES

To examine the efficacy and safety of tadalafil in Asian men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

METHODS

Asian men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia were randomized to once-daily placebo (n=154), tadalafil 2.5 mg (n=151), tadalafil 5.0 mg (n=155) or tamsulosin 0.2 mg (active control, n=152) for 12 weeks.

RESULTS

Total International Prostate Symptom Score least-squares mean changes from baseline to end-point significantly improved with tadalafil 2.5 mg (-4.8, P=0.003) and 5 mg (-4.7, P=0.004) versus placebo (-3.0). Significant improvement in the International Prostate Symptom Score versus placebo was observed earlier (week 2) for tadalafil 5.0 mg than for tadalafil 2.5 mg (week 8). Significant improvements (P<0.05) in both tadalafil groups versus placebo were observed for the International Prostate Symptom Score voiding subscore, International Prostate Symptom Score Quality of Life, and for Patient and Clinician Global Impressions of Improvement. Significant improvements versus placebo were observed in the International Prostate Symptom Score storage subscore for tadalafil 5.0 mg (-1.7, P=0.021), but not tadalafil 2.5 mg (-1.5, P=0.072). No significant improvements in benign prostatic hyperplasia Impact Index or improvements in peak urinary flow rates were observed with tadalafil 2.5 mg or 5.0 mg versus placebo. Tamsulosin treatment resulted in significant improvements versus placebo across all efficacy parameters, except for peak urinary flow rates. Safety results were consistent with the known tadalafil and tamsulosin safety profiles.

CONCLUSIONS

Tadalafil once daily represents an effective and well tolerated medical treatment for Asian men presenting with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

The role of nocturia in the quality of life of men with lower urinary tract symptoms

OBJECTIVES

To determine the role of treatment-associated improvement in nocturia in health-related quality of life (HRQL) in patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia, and secondarily to confirm the role of nocturia in HRQL at baseline and to compare the effects of watchful waiting, transurethral microwave treatment (TUMT) and transurethral resection of the prostate (TURP) to those of α1-adrenoceptor antagonists (α-blockers) on nocturia.

PATIENTS AND METHODS

We retrospectively analysed using multiple regression a large single-centre database of patients receiving routine care for treatment-associated alterations of symptoms and HRQL (assessed at baseline, 2611 men) and 6-12 months after initiation of treatment (1258 men).

RESULTS

Among the symptoms assessed using the International Prostate Symptom Score, nocturia (together with urgency and weak stream) had the strongest correlation with HRQL at baseline and after treatment. Watchful waiting, α-blockers, TUMT and TURP reduced nocturia episodes by a mean (sd) of 7 (53)%, 17 (40)%, 32 (47)% and 75 (23)%, respectively. The treatment-associated improvements in nocturia (together with those of weak stream) had the strongest association with those of HRQL.

CONCLUSIONS

We conclude that among all LUTS assessed in the IPSS, nocturia has one of the strongest associations with HRQL, and that treatment-associated improvements in nocturia contribute considerably to overall improvements in HRQL.

WITHDRAWN: Tamsulosin for benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is a nonmalignant enlargement of the prostate which can result in bothersome lower urinary tract symptoms. The treatment goal for men with BPH is to relieve these bothersome symptoms.

OBJECTIVES

This systematic review assessed the effects of tamsulosin in the treatment of lower urinary tract symptoms (LUTS) compatible with BPH.

SEARCH STRATEGY

Trials were searched in computerized general and specialized databases (MEDLINE, EMBASE, Cochrane Library), by checking bibliographies, and by contacting manufacturers and researchers.

SELECTION CRITERIA

Trials were eligible if they (1) randomized men with BPH to receive tamsulosin in comparison with placebo, other BPH medications or surgical interventions and (2) included clinical outcomes such as urologic symptom scales, symptoms, or urodynamic measurements, and (3) had a treatment duration of 30 days or longer. Eligibility was assessed by at least two independent observers.

DATA COLLECTION AND ANALYSIS

Information on patients, interventions, and outcomes were extracted by at least two independent reviewers using a standard form. The main outcome measure for comparing the effectiveness of tamsulosin with placebo, medical or surgical interventions was the change in urologic symptom scale scores. Secondary outcomes included changes in urinary flow measures (peak urine flow rate). The main outcome measure for adverse effects was the number of men reporting adverse effects.

MAIN RESULTS

Fourteen studies involving 4122 subjects met inclusion criteria. Study duration ranged from 4 to 26 weeks, and no placebo-controlled study lasted longer than 13 weeks. The mean age of subjects was 64 years. Baseline symptom scores and urine flow rates demonstrated that men had moderate LUTS. Tamsulosin improved symptoms and peak urine flow relative to placebo. The weighted mean differences (WMD) for mean change from baseline for the Boyarsky symptom score for 0.4 mg and 0.8 mg doses of tamsulosin relative to placebo were -1.1 points (95% CI = -1.49 to -0.72; 12% improvement) and -1.6 points (95% CI = -2.3 to -1.0; 16% improvement), respectively. The WMD for mean change from baseline in peak urine flow were 1.1 mL/sec (95% CI = 0.59 to 1.51) and 1.1 mL/sec (95% CI= 0.65 to 1.48) for 0.4 mg and 0.8 mg, respectively. Tamsulosin (0.2 mg to 0.4 mg) was as effective as other alpha antagonists and the phytotherapeutic agent Permixon® in improving symptoms and flow rates though the doses of all alpha-antagonists studied may not have been optimal. Discontinuations from treatment for any reason and discontinuations "due to adverse events" were similar in the low dose tamsulosin (0.2 mg) and placebo groups but increased to 16% in trials utilizing a 0.8 mg dose of tamsulosin. Low dose tamsulosin was generally well tolerated although not all the trials reported specific adverse events. The most frequently reported adverse events that were significantly greater than placebo included dizziness, rhinitis and abnormal ejaculation. Adverse effects increased markedly as tamsulosin dosing increased, and were reported in 75% of men receiving the 0.8 mg dose. Men receiving a 0.2 mg dose tamsulosin were less likely to discontinue treatment compared to men receiving terazosin.

AUTHORS' CONCLUSIONS

Tamsulosin provided a small to moderate improvement in urinary symptoms and flow compared to men receiving placebo in men with BPH. Effectiveness was similar to other alpha antagonists and increased only slightly with higher doses. Long term effectiveness and ability to reduce complications due to BPH progression could not be determined. Adverse effects were generally mild but their frequency, including withdrawals, increased substantially with the higher doses that are generally available for treatment.

Non-inferiority of silodosin to tamsulosin in treating patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH)

What's known on the subject? and What does the study add? Silodosin administered by 4 mg twice daily is as effective as tamsulosin 0.2 mg daily in treating patients with LUTS associated with BPH. Relative to tamsulosin, silodosin has less cardiovascular side effects as judged by the minimal changes of blood pressure and pulse rats after treatment.

OBJECTIVE

• To test the hypothesis that the efficacy of silodosin would not be inferior to tamsulosin in treating patients with lower urinary tract symptoms associated with benign prostate hyperplasia (BPH).

PATIENTS AND METHODS

• At nine medical centres, 209 patients with an International Prostate Symptom Score (IPSS) of ≥13 were randomized to silodosin (4 mg twice daily) or tamsulosin (0.2 mg once daily) for 12 weeks. • The primary efficacy measure was the mean change from baseline to endpoint in IPSS. • The non-inferiority margin of the IPSS change was set at 1.0. • Secondary efficacy measures included change in maximal urinary flow rate (Q(max)) and health-related quality of life (HRQL) score.

RESULTS

• Of the 170 (81.3%) patients who completed the study, 86.2% in the silodosin group vs 81.9% in the tamsulosin group achieved a ≥25% decrease in IPSS (P= 0.53). • The mean difference (silodosin minus tamsulosin) in IPSS change from baseline was -0.60 (95% confidence interval -2.15, 0.95), inferring the non-inferiority of silodosin to tamsulosin. • The mean changes in the Q(max) and HRQL score from baseline were comparable between the groups (both, P > 0.05). Although patients receiving silodosin had a significantly higher incidence of abnormal ejaculation (9.7% vs tamsulosin 1.0%, P= 0.009), only 1.9% discontinued treatment. • Tamsulosin treatment resulted in a significant reduction in mean systolic blood pressure (-4.2 mmHg, within-group P= 0.004) relative to the negligible change of silodosin (-0.1 mmHg, within-group P= 0.96)

CONCLUSION

• The trial shows the non-inferiority of silodosin 4 mg twice daily to tamsulosin 0.2 mg once daily in patients with symptoms of BPH.

A Randomized Crossover Study Comparing Patient Preference for Tamsulosin and Silodosin in Patients with Lower Urinary Tract Symptoms Associated with Benign Prostatic Hyperplasia

Patient preference for benign prostatic hyperplasia (BPH) treatment with the α1-blockers, tamsulosin or silodosin, was compared using patient-reported outcomes. Japanese patients with lower urinary tract symptoms associated with BPH were randomly allocated to either the T–S group (tamsulosin 0.2 mg orally once daily for 4 weeks then silodosin 4 mg orally twice daily for 4 weeks) or the S–T group (silodosin 4 mg orally twice daily for 4 weeks then tamsulosin 0.2 mg orally once daily for 4 weeks). The primary endpoint was the preferred drug for treatment continuation at 8 weeks, determined by a patient-reported questionnaire. In total, 102 patients (mean age 70.3 years) were enrolled and 84 ( n = 42 per group) completed the study. A significant difference was observed between the proportion of patients who preferred tamsulosin (59/84 patients; 70.2%) and those who preferred silodosin (18/84 patients; 21.4%). A major reason for preference of either drug was ‘good efficacy’. Incidence of adverse effects was significantly lower with tamsulosin (3/91 patients; 3.3%) than with silodosin (25/88 patients; 28.4%). These findings indicate that tamsulosin is very effective for BPH, has few adverse effects and that patients want to continue to use it.

Facilitation of expulsion of ureteral stones by addition of α1-blockers to conservative therapy

OBJECTIVE

An antispasmodic agent and a medicine that facilitates stone expulsion are given commonly as conservative therapy for ureteral stones in Japan. The goal of this study was to compare the efficacy of the addition of various α(1)-blockers to the conservative therapy for spontaneous passage of ureteral stones.

MATERIAL AND METHODS

The subjects were 132 patients with stones from the upper to the lower ureter who were randomly placed into one of four groups and followed for 1 month to assess spontaneous passage of stones. The control group received daily doses of 240 mg flopropione as an antispasmodic agent and 1350 mg extract of Quercus salicina Blume/Quercus stenophylla Makino as a medicine that facilitates stone expulsion. The other three groups received this therapy and daily doses of 30 mg urapidil, 0.2 mg tamsulosin or 50 mg naftopidil, respectively. The characteristics of the stones and stone expulsion were evaluated by urinalysis, a kidney, ureter and bladder (KUB) X-ray, ultrasound and computed tomography.

RESULTS

All patients completed the study and there were no major side-effects. There was no difference in age, stone position or stone size among the groups. Multivariate analysis using a Cox proportional hazards model indicated that the probability of stone expulsion for 1 month was increased 2.38 times (95% confidence interval 1.23-4.61) by naftopidil compared with control therapy alone (p = 0.01).

CONCLUSION

Naftopidil in combination with an antispasmodic agent and a medicine that facilitates stone expulsion produces a significantly increased rate of ureteral stone expulsion.

Effects of tamsulosin on bladder blood flow and bladder function in rats with bladder outlet obstruction

OBJECTIVES

To investigate the mechanism underlying the ameliorating effect of tamsulosin, an alpha(1)-adrenoceptor antagonist, on storage symptoms associated with benign prostatic hyperplasia, the effects of tamsulosin on bladder blood flow (BBF) and bladder function was evaluated in rats with bladder outlet obstruction (BOO).

METHODS

BOO was produced by partial ligature of the proximal urethra, which was maintained for 2 weeks. Tamsulosin was subcutaneously administered via an osmotic pump for 2 weeks immediately after the BOO surgery. The BBF in the sham-operated rats, the control BOO rats, and the tamsulosin-treated BOO rats was measured using the fluoromicrosphere method. Each rat was kept in a metabolic cage for observation of micturition behavior. Expression of the alpha(1)-adrenoceptor subtype mRNA in the vesical artery was measured by reverse transcriptase-polymerase chain reaction.

RESULTS

BBF was significantly reduced in BOO rats compared with sham-operated rats, and tamsulosin significantly increased the BBF in BOO rats. Tamsulosin ameliorated the decrease in mean voided volume in BOO rats with bladder masses < 500 mg. Expression of the alpha(1)-adrenoceptor subtype in the vesical artery was alpha(1a)- > alpha(1d)-adrenoceptors; almost no expression was observed of alpha(1b)-adrenoceptors in either sham-operated or BOO rats.

CONCLUSIONS

Tamsulosin increased BBF in BOO rats via an antagonistic effect, presumably on the alpha(1A)- and/or alpha(1D)-adrenoceptor in the vesical artery mainly, and improved the decrease in mean voided volume. Therefore, the results of this study suggest that tamsulosin improves bladder overactivity via improvement of BBF.

A meta-analysis of the vascular-related safety profile and efficacy of alpha-adrenergic blockers for symptoms related to benign prostatic hyperplasia

OBJECTIVES

To evaluate the safety profile and efficacy of alpha1-adrenergic receptor blockers (A1Bs) currently prescribed for benign prostatic hyperplasia (BPH).

DATA SOURCES

A systematic literature search of MEDLINE, the Cochrane Database and the Food and Drug Administration Web site through December 2006 identified double-blinded, prospective, placebo-controlled trials, evaluating agents commercially available by prescription for the symptomatic treatment of BPH.

REVIEW METHODS

Data were reviewed by two investigators with the use of a standardised data abstraction form. Studies were evaluated for methodological quality using the Jadad scale. Studies with a score of < 3 were considered of weaker methodology.

RESULTS

Of 2389 potential citations, 25 were usable for evaluation of safety data, 26 for efficacy. A1B use was associated with a statistically significant increase in the odds of developing a vascular-related event [odds ratio (OR) 2.54; 95% confidence interval (CI): 2.00-3.24; p < 0.0001]. The odds of developing a vascular-related adverse event were: alfuzosin, OR 1.66, 95% CI: 1.17-2.36; terazosin, OR 3.71, 95% CI: 2.48-5.53; doxazosin, OR 3.32, 95% CI: 2.10-5.23 and tamsulosin, OR 1.42, 95% CI: 0.99-2.05. A1Bs increased Q(max) by 1.32 ml/min (95% CI: 1.07-1.57) compared with placebo. Difference from placebo in American Urological Association symptom index/International Prostate Symptom Score was -1.92 points (95% CI: -2.71 to -1.14).

CONCLUSIONS

Alfuzosin, terazosin and doxazosin showed a statistically significant increased risk of developing vascular-related events compared with placebo. Tamsulosin showed a numerical increase that was not statistically significant. All agents significantly improved Q(max) and symptom signs compared with placebo.

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.

Hepatic metabolism of two alpha-1A-adrenergic receptor antagonists, phthalimide-phenylpiperazine analogs (RWJ-69205 and RWJ-69471), in the rat, dog and human

The In vitro metabolism of two alpha-1A-adrenergic antagonists, RWJ-69205 and RWJ-69471 (phthalimide-phenylpiperazine analogs), was assessed after 30 and 60 min incubations with rat, dog and human hepatic S9 fractions in the presence of an NADPH-generating system. Unchanged RWJ-69205 (> or = 72% of the sample in all species) plus 3 metabolites from the RWJ-69205 incubations, and unchanged RWJ-69471 (> or = 60% of the sample in all species) and 7 metabolites from the RWJ-69471 incubations, were profiled, quantified, and tentatively identified on the basis of API-MS and MS/MS data. The formation of RWJ-69205 and RWJ-69471 metabolites are via the following five metabolic pathways: 1. phenylhydroxylation, 2. O-dealkylation, 3. oxidative N-dealkylation, 4. N-dephenylation, and 5. dehydration. Pathway 1 formed 2 major/moderate hydroxy-phenyl metabolites of 2 analogs (4-17%) in all species, and pathway 2 produced 2 O-desisopropyl metabolites of 2 analogs in major/moderate (7-16%) in rat and human, and in trace (< 1%) in dog; in conjunction with pathway 1, yielded a minor diphenolic metabolite (< 1-2%) in RWJ-69471. Pathway 3 formed a minor N-dealkylated metabolite, isopropoxyphenyl piperazine (< 1-6%) in all species of 2 analogs. Pathways 4 and 5 produced 2 minor N-desphenyl metabolite and dehydrated metabolite, respectively, in rat and human S9 (< or = 1-2%) in RWJ-69471. Both RWJ-69205 and RWJ-69471 were less extensively metabolized in the dog. However, rat and human appeared to metabolize RWJ-69471 more extensively than RWJ-69205 in this hepatic system.

Silodosin, a new alpha1A-adrenoceptor-selective antagonist for treating benign prostatic hyperplasia: results of a phase III randomized, placebo-controlled, double-blind study in Japanese men

OBJECTIVE

To verify the efficacy and safety of the new alpha1A-adrenoceptor-selective antagonist silodosin compared with tamsulosin and placebo in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

This randomized, double-blind, placebo-controlled study was conducted at 88 centres in Japan. Men aged > or = 50 years with an International Prostate Symptom Score (IPSS) of > or = 8, a quality-of-life (QoL) score of > or = 3, a maximum urinary flow rate (Qmax) of < 15 mL/s, a prostate volume of > or = 20 mL and a postvoid residual urine volume of < 100 mL were eligible for enrolment. Patients were randomized to receive silodosin 4 mg twice daily, tamsulosin 0.2 mg once daily, or placebo, for 12 weeks. The primary endpoint was the change in IPSS from baseline. Safety was assessed by adverse events, physical examination, vital signs and laboratory tests.

RESULTS

In all, 457 patients were randomized (silodosin 176, tamsulosin 192 and placebo 89). The change in the total IPSS from baseline in the silodosin, tamsulosin and placebo groups was -8.3, -6.8 and -5.3, respectively. There was a significant decrease in the IPSS vs placebo in the silodosin group from 1 week. In the early-stage comparison, silodosin showed a significant decrease in IPSS vs tamsulosin at 2 weeks. The change in QoL from baseline was -1.7, -1.4 and -1.1 in the silodosin, tamsulosin and placebo groups, respectively; silodosin showed a significant improvement in the QoL score vs placebo. In the subgroup of patients with severe symptoms (IPSS > or = 20) silodosin also gave a significantly better improvement than placebo (-12.4 vs -8.7). The incidence rates of adverse events and drug-related adverse events were, respectively, 88.6%, 82.3% and 71.6% and 69.7%, 47.4% and 36.4%, respectively. The most common adverse event in the silodosin group was abnormal ejaculation, which occurred more often in the silodosin than in the tamsulosin group (22.3% vs 1.6%). However, only five men (2.9%) discontinued treatment for abnormal ejaculation.

CONCLUSION

Silodosin was generally effective in the absence of obtrusive side-effects. This study suggests that silodosin is clinically useful for treating LUTS associated with BPH.

Comparison of 25 and 75 mg/day naftopidil for lower urinary tract symptoms associated with benign prostatic hyperplasia: A prospective, randomized controlled study

BACKGROUND

The present study investigated the efficacy, safety, and utility of starting an alpha(1d)-selective antagonist, naftopidil, at 75 or 25 mg/day in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH).

METHODS

In this prospective comparative study, the subjects comprised 153 patients with LUTS associated with BPH. Patients were randomized to receive either 25 mg/day (Group LD) or 75 mg/day (Group HD) of naftopidil for 4 weeks. The lower urinary tract disease symptom score (LUTDSS), the International Prostate Symptom Score (IPSS), the Quality of life assessment index, the maximum flow rate (Q(max)), and the residual urine volume were compared between the groups.

RESULTS

In both groups, the LUTDSS and the IPSS were significantly improved at the endpoint and no significant intergroup differences were identified. However, the improvement in the Q(max) was significantly better for Group HD than for Group LD. The overall efficacy did not differ significantly between the groups. The degree of improvement in voiding symptoms and LUTDSS among patients with moderate symptoms was significantly greater for Group HD than for Group LD. The frequency of adverse reactions did not differ significantly between the groups.

CONCLUSIONS

Starting administration at 75 mg/day rather than 25mg/day is helpful for LUTS associated with BPH for patients with moderate symptoms, particularly in improving voiding symptoms. The 75 mg/day administration was considered to be a recommendable therapeutic dose in some patients.

[Alpha1-adrenoceptor subtypes and alpha1-adrenoceptor antagonists]

Alpha(1)-adrenoceptors are widely distributed in the human body and play important physiologic roles. Three alpha(1)-adrenoceptor subtypes (alpha(1A), alpha(1B) and alpha(1D)) have been cloned and show different pharmacologic profiles. In addition, a putative alpha(1)-adrenoceptor (alpha(1L) subtype) has also been proposed. Recently, three drugs (tamsulosin, naftopidil, and silodosin) have been developed in Japan for the treatment of urinary obstruction in patients with benign prostatic hyperplasia. In this review, we describe recent alpha(1)-adrenoceptor subclassifications and the pharmacologic characteristics (subtype selectivity and clinical relevance) of alpha(1)-adrenoceptor antagonists.

Comparison of two alpha1-adrenoceptor antagonists, naftopidil and tamsulosin hydrochloride, in the treatment of lower urinary tract symptoms with benign prostatic hyperplasia: a randomized crossover study

OBJECTIVES

To compare the efficacy of two alpha(1)-adrenoceptor antagonists, alpha(1A)-adrenoceptor-selective tamsulosin hydrochloride and alpha(1D)-adrenoceptor-selective naftopidil, in the treatment of lower urinary tract symptoms (LUTS) with benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Thirty-four patients (mean age 72.4 years, sd 4.3, range 66-79) with LUTS (International Prostate Symptom Score, IPSS >8) secondary to BPH were enrolled in a randomized crossover study. Seventeen patients were initially prescribed naftopidil 50 mg for 4 weeks, followed by tamsulosin 0.2 mg for 4 weeks (group A); another 17 were initially prescribed tamsulosin 0.2 mg, followed by naftopidil 50 mg (group B). Patients changed to the alternative treatment after a 1-week washout period. Efficacy criteria were improvement in LUTS (IPSS), quality of life (QoL), uroflowmetry, and pressure-flow study (PFS) values based on the treatment with each agent.

RESULTS

At baseline there were no significant differences between the groups in IPSS, QoL, uroflowmetry values or PFS values, except for the volume at maximum desire to void. After treatment with each agent, the IPSS and QoL were significantly improved and the reduction in bladder outlet obstruction confirmed by PFS. Naftopidil was significantly more effective than tamsulosin in relieving nocturia. The increases from baseline (before treatment) to the endpoint (after treatment with each agent) in the volume at first desire and maximum desire to void were significantly higher with naftopidil than with tamsulosin. Involuntary contractions disappeared in two patients with relief of nocturia with naftopidil, but not with tamsulosin. The decrease in other symptoms of the IPSS, QoL, increase in uroflowmetry values and changes in other PFS values were similar for both agents.

CONCLUSIONS

The two agents provided similar efficacy in the treatment of LUTS with BPH. However, naftopidil was better than tamsulosin for nocturia. The disappearance of involuntary contraction and the greater increase in first-desire volume with naftopidil may be associated with the relief of nocturia. The alpha(1D)-adrenoceptor antagonist is effective in alleviating both voiding and storage symptoms. The alpha(1D)-adrenoceptor antagonist may be more effective than the alpha(1A)-adrenoceptor antagonist in LUTS with BPH.

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.

Metabolism of the alpha-1A-adrenergic receptor antagonist, pyridine-phenylpiperazine analog (RWJ-69597), in rat, dog and human hepatic S9 fractions -API-MS/MS identification of metabolites

The In vitro metabolism of the alpha-1A-adrenergic antagonist, RWJ-69597, an analog of pyridine-phenylpiperazines, was conducted after incubation with rat, dog and human hepatic S9 fractions in the presence of an NADPH-generating system. Unchanged RWJ-69597 (> or =43% of the sample in all species) plus 9 metabolites were profiled, quantified, and tentatively identified on the basis of API-MS and MS/MS data. The four metabolic pathways for the formation of RWJ-69597 metabolites are: 1. methyl/phenyl/piperazinylhydroxylation, 2. N/Odealkylation, 3. N-dephenylation, and 4. dehydration. Pathway 1 formed 1 major (8-36%) and 3 minor (<1-3%) hydroxylated metabolites. Pathway 2 produced 2 moderate/minor N/O-dealkylated metabolites (<1- < or =11%), and in conjunction with pathway 1, formed 1 minor diol metabolites (< or =2%). Pathways 3 and 4 generated 2 minor metabolites, N-desphenyl RWJ-69597 (< or =4%) and dehydrated RWJ-69597 (< or =2%), respectively. RWJ-69597 is more extensively metabolized in the rat than the dog or the human in this hepatic system.

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.

Metabolism of the new α-1A-adrenergic receptor antagonist, phthalimide-phenylpiperazine analog (RWJ-69442), in rat, dog and human hepatic S9 fractions, and in rats

The in vitro and in vivo metabolism of RWJ-69442, an alpha-1A-adrenergic receptor antagonist, was investigated after incubation with rat, dog, and human hepatic S9 fractions in the presence of NADPH-generating system, and a single oral/iv dose administration to rats (oral: 100 mg/kg; iv: 10 mg/kg). Unchanged RWJ-69442 (> or =30% of the sample in vitro; < or =47% of the sample in vivo) plus 14 metabolites were profiled, quantified and tentatively identified on the basis of API-MS and MS/MS data. The metabolic pathways for RWJ-69442 are proposed via the 4 steps: 1. phenyl/piperazinylhydroxylation, 2. N/O-dealkylation, 3. N-dephenylation, and 4. dehydration. Pathway 1 formed OH-phenyl-RWJ-69442 (M1, 4-32% in vitro & in vivo), and diOH-RWJ-69442 (M4, <1-4% in vitro & in vivo). Pathway 2 generated O-desisopropyl-RWJ-69442 (M2, <1-21% in vitro & in vivo), N-desmethyl-RWJ-69442 (M3, 2-3% in vitro & in vivo), N-desmethyl-M2 (M6, 1-8% in vitro & in vivo), and N-dealkylated RWJ-69442 (M9, < or =1-17% in vitro & in vivo), and in conjunction with pathway 1 produced 6 minor to major oxidized metabolites, OH-M2 (M5, 1-2% in vitro), OH-M3 (M11, 4-6% in vivo), OH-M9 (M10, <1-34% in vitro & in vivo), O-desisopropyl-M9 (M12, 3-21% in vivo), O-desisopropyl-M10 (M13,2-12% in vivo), and dehydro-M13 (M14, 25% in vivo). Pathways 3 and 4 formed 2 minor metabolites, N-desphenyl-RWJ-69442 (M7, <1-12% in vitro & in vivo) and dehydrated-RWJ-69442 (M8, <1-2% in vitro), respectively. RWJ-69442 is extensively metabolized in vitro in the rat and human (except dog), and in vivo in the rat.

Medical therapy for benign prostatic hyperplasia: sexual dysfunction and impact on quality of life

Therapies for benign prostatic hyperplasia (BPH) may either improve or exacerbate sexual function with an ensuing impact on quality of life. Here we review a total of 73 papers on medical therapies for BPH with a focus on the effects of different pharmacological agents on sexual function. For example, certain alpha(1)-adrenergic receptor blockers may improve erectile function; however, ejaculatory dysfunction with one of these agents, tamsulosin, occurs at a rate of 4-18%, rising to 30% with long-term use. In addition, treatment with the 5 alpha-reductase inhibitor finasteride is associated with problems of ejaculation (2.1-7.7%), erection (4.9-15.8%), and libido (3.1-5.4%). Such significant and undesirable complications in relation to sexual function produce a well-documented negative impact on quality of life. Thus, optimal treatment for men with BPH requires the use of agents that demonstrate efficacy and safety with fewer sexual side effects.

Tamsulosin for benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is a nonmalignant enlargement of the prostate which can result in bothersome lower urinary tract symptoms. The treatment goal for men with BPH is to relieve these bothersome symptoms.

OBJECTIVES

This systematic review assessed the effects of tamsulosin in the treatment of lower urinary tract symptoms (LUTS) compatible with BPH.

SEARCH STRATEGY

Trials were searched in computerized general and specialized databases (MEDLINE, EMBASE, Cochrane Library), by checking bibliographies, and by contacting manufacturers and researchers.

SELECTION CRITERIA

Trials were eligible if they (1) randomized men with BPH to receive tamsulosin in comparison with placebo, other BPH medications or surgical interventions and (2) included clinical outcomes such as urologic symptom scales, symptoms, or urodynamic measurements, and (3) had a treatment duration of 30 days or longer. Eligibility was assessed by at least two independent observers.

DATA COLLECTION AND ANALYSIS

Information on patients, interventions, and outcomes were extracted by at least two independent reviewers using a standard form. The main outcome measure for comparing the effectiveness of tamsulosin with placebo, medical or surgical interventions was the change in urologic symptom scale scores. Secondary outcomes included changes in urinary flow measures (peak urine flow rate). The main outcome measure for adverse effects was the number of men reporting adverse effects.

MAIN RESULTS

Fourteen studies involving 4,122 subjects met inclusion criteria. Study duration ranged from 4-26 weeks, and no placebo-controlled study lasted longer than 13 weeks. The mean age of subjects was 64 years. Baseline symptom scores and urine flow rates demonstrated that men had moderate LUTS. Tamsulosin improved symptoms and peak urine flow relative to placebo. The weighted mean differences (WMD) for mean change from baseline for the Boyarsky symptom score for 0.4 mg and 0.8 mg doses of tamsulosin relative to placebo were -1.1 points (95% CI = -1.49, -0.72; 12% improvement) and -1.6 points (95% CI = -2.3, -1.0; 16% improvement), respectively. The WMD for mean change from baseline in peak urine flow were 1.1 mL/sec (95% CI = 0.59, 1.51) and 1.1 mL/sec (95% CI= 0.65, 1.48) for 0.4 mg and 0.8 mg, respectively. Tamsulosin (0.2 mg-0.4 mg) was as effective as other alpha antagonists and the phytotherapeutic agent Permixon in improving symptoms and flow rates though the doses of all alpha-antagonists studied may not have been optimal. Discontinuations from treatment for any reason and discontinuations "due to adverse events" were similar in the low dose tamsulosin (0.2 mg) and placebo groups but increased to 16% in trials utilizing a 0.8 mg dose of tamsulosin. Low dose tamsulosin was generally well tolerated although not all the trials reported specific adverse events. The most frequently reported adverse events that were significantly greater than placebo included dizziness, rhinitis and abnormal ejaculation. Adverse effects increased markedly as tamsulosin dosing increased, and were reported in 75% of men receiving the 0.8 mg dose. Men receiving a 0.2 mg dose tamsulosin were less likely to discontinue treatment compared to men receiving terazosin.

REVIEWER'S CONCLUSIONS

Tamsulosin provided a small to moderate improvement in urinary symptoms and flow compared to men receiving placebo in men with BPH. Effectiveness was similar to other alpha antagonists and increased only slightly with higher doses. Long term effectiveness and ability to reduce complications due to BPH progression could not be determined. Adverse effects were generally mild but their frequency, including withdrawals, increased substantially with the higher doses that are generally available for treatment.

Tamsulosin: a review of its pharmacology and therapeutic efficacy in the management of lower urinary tract symptoms

Tamsulosin is a subtype-selective alpha(1A)- and alpha(1D )-adrenoceptor antagonist. alpha(1)-Receptors predominate in the prostate gland, prostatic capsule, prostatic urethra and bladder, and the relaxation of prostate and bladder smooth muscles is associated with improved maximal urine flow (Q(max)) and alleviation of lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH). Tamsulosin 0.4 mg once daily in a modified-release formulation increased Q(max) and improved symptom scores relative to baseline to a greater extent than placebo in 12- and 13-week double-blind, randomised, multicentre, clinical trials in patients with LUTS, with statistical significance between treatments for Q(max) values in two of three published US and European studies. Tamsulosin is effective in patients with mild to severe LUTS associated with BPH, in patients with diabetes mellitus and in the elderly, and does not interfere with concomitant antihypertensive therapy. Pooled data based on patients receiving tamsulosin 0.4 or 0. 8mg once daily indicate maintenance of efficacy for up to 6 years. Tamsulosin 0.4 mg once daily was of similar efficacy to alfuzosin 2.5 mg three times daily, with less tendency to cause hypotensive effects, in a double-blind, randomised 12-week trial. Benefit of the drug has also been shown in patients with acute urinary retention or chronic abacterial prostatitis, those receiving high energy transurethral microwave thermotherapy, and in patients with prostate cancer with radiation-induced urethritis. Dizziness and abnormal ejaculation are stated to be the most common adverse events, with asthenia, postural hypotension and palpitations being seen less frequently (1 to 2% incidence), in patients receiving tamsulosin 0.4 mg once daily. Tamsulosin has not been associated with clinically significant changes in blood pressure in clinical trials.

CONCLUSION

The alpha(1A)- and alpha(1D)-adrenoceptor antagonist tamsulosin, given at a dosage of 0.4 mg once daily in a modified-release formulation, is effective and well tolerated in the treatment of LUTS associated with BPH. Although the drug has been directly compared to date with one other agent only, data show overall that tamsulosin clearly offers advantages over other alpha(1)-adrenoceptor antagonists in terms of the need for a single daily dose only, and its low potential for hypotensive effects or interference with concomitant antihypertensive therapy. Dosage titration at the start of treatment is not necessary. Tamsulosin has a rapid onset of action and is effective in patients with moderate or severe symptoms. The drug is therefore a valuable therapeutic option, with both demonstrated and potential advantages over older nonselective agents, in the management of patients with LUTS associated with BPH.

Tamsulosin: an update of its role in the management of lower urinary tract symptoms

Tamsulosin is a selective alpha1A- and alpha1D-adrenoceptor antagonist. These alpha1-receptors are predominant in the prostate, prostatic capsule, prostatic urethra and bladder. The relaxation of prostate and bladder smooth muscles may result in improvement in maximum urine flow (Qmax) and reduction of lower urinary tract symptoms (LUTS). Tamsulosin 0.4 and 0.8 mg/day in a modified-release formulation was significantly more effective than placebo in large (n >250) double-blind, randomised, multicentre, 12- to 13- week clinical trials in patients with LUTS. A greater increase in Qmax from baseline was seen in patients receiving tamsulosin 0.4 or 0.8 mg/day (1.4 to 1.79 ml/sec from a baseline of 9.46 to 10.7 ml/sec) than in placebo recipients (0.4 to 0.93 ml/sec from a baseline of 9.75 to 10.4 ml/sec); the between-group difference was significant in two of three studies. Tamsulosin 0.4 or 0.8 mg/day improved total Boyarsky symptom scores from baseline by a significantly greater extent (by 3.0 to 5.2 points from a baseline of 9.5 to 11.1 points) than placebo (1.9 to 3.2 points from a baseline of 9.3 to 11.0 points). In noncomparative extension studies, the improvement in efficacy parameters with tamsulosin treatment was maintained for up to 4 years. Tamsulosin is effective in patients with mild to severe LUTS, patients with diabetes mellitus or those aged > or = 65 years and does not interfere with the antihypertensive action of nifedipine, enalapril or atenolol. Tamsulosin 0.4 mg/day for 12 weeks and tamsulosin 0.2 mg/day for 4 weeks were as effective as alfuzosin 2.5mg three times daily and terazosin 2 mg/day, respectively, in improving Qmax and symptom scores in randomised comparative trials. With the exception of a numberically greater incidence of abnormal ejaculation, dizziness and rhinitis, the incidence of adverse events with tamsulosin 0.4 mg/day was similar to that seen with placebo in randomised, double-blind studies. The overall incidence of symptoms indicative of orthostasis was 1.4% with tamsulosin 0.4 or 0.8 mg/day treatment. Tamsulosin had less effect on blood pressure than alfuzosin or terazosin.

CONCLUSION

Tamsulosin, an alpha1-adrenoceptor antagonist, has a well established place in the treatment of LUTS and has a tolerability profile similar to that of placebo (apart from a higher incidence of abnormal ejaculation, dizziness and rhinitis). Comparative data have shown tamsulosin to be as effective as other alpha1-adrenoceptor antagonists at increasing Qmax and improving symptom scores. However, tamsulosin is unlikely to produce orthostatic hypotensive adverse effects or interfere with concomitant antihypertensive drug therapy. Therefore, tamsulosin is a useful therapeutic option in the management of patients with moderate to severe LUTS.

Effects of the concomitant administration of tamsulosin (0.8 mg) on the pharmacokinetic and safety profile of intravenous digoxin (Lanoxin) in normal healthy subjects: a placebo-controlled evaluation

A 20-day, nonrandomized, open-label, placebo-controlled study was performed to investigate whether concomitant administration of tamsulosin (0.8 mg) affects the pharmacokinetic and safety profile of intravenous digoxin (0.5 mg) in healthy subjects. Ten healthy subjects aged 21-39 years received a single oral dose of placebo on study days 1-8 and tamsulosin on days 9-18. Tamsulosin was initiated at 0.4 mg/day and the dose was increased to 0.8 mg/day from day 11. On days 2 and 15, subjects received a single intravenous dose of digoxin (0.5 mg). Safety monitoring was carried out throughout the study. Following digoxin administration, blood was drawn and urine collected over a 96-h period for pharmacokinetic determinations. Plasma tamsulosin concentrations were measured at regular intervals after dosing on day 15. The digoxin pharmacokinetic parameters with and without concomitant tamsulosin were compared. No significant difference was observed, and no irregularity was found in the plasma tamsulosin concentration data. Six subjects experienced adverse events while receiving placebo and seven while on tamsulosin. The most frequent adverse event was mild dizziness reported by four subjects. Moderate chest pain was reported in two subjects, but this was not considered to be related to the administration of the study medications. Some significant changes in vital signs were observed; however, none was accompanied by symptoms of medical concern. These changes were not temporally related to the administration of study drugs. Thus, concurrent administration of digoxin with tamsulosin did not produce any change in the pharmacokinetics of digoxin and the safety profile was acceptable. As reflected in the prescribing information for tamsulosin, no adjustment in tamsulosin dosing is required when it is administered concomitantly with digoxin.

Effects of the concomitant administration of tamsulosin (0.8 mg/day) on the pharmacokinetic and safety profile of theophylline (5 mg/kg): a placebo-controlled evaluation

We performed a single-blind, sequential-design study to investigate the effects of concomitant oral tamsulosin 0.8 mg/day on the pharmacokinetics and safety of intravenous theophylline 5 mg/kg in healthy subjects. Ten healthy volunteers aged 19-39 years received placebo on study days 0, 1, 2 and 10 and tamsulosin on days 3-9. Theophylline was administered intravenously on days 1 and 9. Theophylline and tamsulosin pharmacokinetic data were determined following administration of the drugs on days 1 and 9 and day 9, respectively. No differences were observed in theophylline pharmacokinetic parameters with and without concomitant tamsulosin, and there were no abnormalities in tamsulosin pharmacokinetic data. Some significant changes in vital signs and a number of mild adverse reactions were reported, but the overall safety profile of tamsulosin and theophylline was acceptable. The results of the study suggest that no dose adjustment in tamsulosin is necessary when it is administered concomitantly with theophylline.