Effect of naftopidil on urethral obstruction in benign prostatic hyperplasia: assessment by urodynamic studies

Association of silodosin, tamsulosin, and naftopidil with delirium: analysis of the pharmacovigilance database in Japan

BACKGROUND

An association between adrenergic alpha-1 receptor antagonists and delirium has been suggested, but the details are unclear.

AIM

This study investigated the association between adrenergic alpha-1 receptor antagonists and delirium in patients with benign prostatic hyperplasia using the Japanese Adverse Drug Event Report database.

METHOD

First, disproportionality analysis compared the frequency of delirium in the adrenergic alpha-1 receptor antagonists silodosin, tamsulosin, and naftopidil. Next, multivariate logistic analysis was performed to examine the association between delirium and adrenergic alpha-1 receptor antagonists where disproportionality was detected.

RESULTS

A disproportionality in delirium was observed in patients receiving tamsulosin (reporting odds ratio [ROR] 1.85, 95% confidence interval [CI] 1.38-2.44, P < 0.01) compared with those who did not, and also in patients receiving naftopidil (ROR 2.23, 95% CI 1.45-3.28, P < 0.01) compared with those who did not. Multivariate logistic analysis revealed that in addition to previously reported risk factors for delirium, delirium in patients receiving tamsulosin was significantly increased with concomitant use of anticholinergics (odds ratio 2.73, 95% CI 1.41-5.29, P < 0.01) and delirium in patients receiving naftopidil was significantly increased with concomitant use of beta3-adrenergic receptor agonists (odds ratio 4.19, 95% CI 1.66-10.6, P < 0.01).

CONCLUSION

Anticholinergics or beta3-adrenergic receptor agonists to treat overactive bladder in patients receiving tamsulosin and naftopidil was strongly associated with delirium. Confirming the medical history and concomitant medications of patients receiving tamsulosin or naftopidil may contribute to preventing delirium in patients with benign prostatic hyperplasia and to improving their outcomes.

Management of benign prostate hyperplasia (BPH) by combinatorial approach using alpha-1-adrenergic antagonists and 5-alpha-reductase inhibitors

Currently, the main available treatments for benign prostate hyperplasia (BPH) are alpha-1 adrenergic receptor antagonists (ARAs), 5-alpha reductase inhibitors (5-αRI), anticholinergics, and Phosphodiesterase-5 inhibitors. Recent studies support the combined therapy approach using ARAs with 5-αRI for lower urinary tract symptoms (LUTS) in BPH patients at risk of clinical progression. We aimed to review BPH management in select group of randomized controlled trials by combination therapy with ARAs and 5-αRIs compared to monotherapy with either drug with respect to the safety and efficacy. A total of 6 randomized controlled trials (RCTs) involving comparison of combination therapy with monotherapy using ARAs and 5-αRIs were retrieved from PubMed Central and reviewed for international prostate symptom score (IPSS), quality of life (QoL), post-residual urinary flow rate (PUF), and clinical progression. The results significantly favour the treatment group that received the combination therapy in comparison with the groups receiving monotherapy. However, outcome with regard to prostate volume showed insignificant improvement when the combination therapy is compared with 5- αRIs alone, rather than ARAs. In conclusion, combination therapy using ARAs and 5-αRI is better than monotherapy in the patients of BPH. Fixed dose combination (FDC), a type of combination, is also cost-effective and its side-effects profile resembles to that of monotherapy.

Emerging drugs to target lower urinary tract symptomatology (LUTS)/benign prostatic hyperplasia (BPH): focus on the prostate

OBJECTIVES

The benign prostatic syndrome, comprising lower urinary tract symptomatology secondary to benign prostatic hyperplasia/enlargement, represents a major health care issue in westernized countries. The pharmacological management involves alpha-adrenoceptor antagonists, intervention into the hormonal control of prostate growth using inhibitors of the enzyme 5-alpha-reductase, and stimulation of the nitric oxide/cyclic GMP pathway by tadalafil, an inhibitor of the phosphodiesterase type 5.

METHODS

This review summarizes the achievements which have been made in the development of drug candidates assumed to offer opportunities as beneficial treatment options in the management of the benign prostatic syndrome.

RESULTS

A review of the literature has revealed that the line of development is focusing on drugs interfering with peripheral neuromuscular/neuronal mechanisms (nitric oxide donor drugs, agonists/antagonists of endogenous peptides, botulinum toxin, NX-1207), the steroidal axis (cetrorelix) or the metabolic turn-over (lonidamine), as well as the combination of drugs already established in the treatment of lower urinary tract symptomatology/benign prostatic hyperplasia (phosphodiesterase 5 inhibitor plus alpha-adrenoceptor antagonist).

CONCLUSION

Many research efforts have provided the basis for the development of new therapeutic modalities for the management of lower urinary tract dysfunctions, some of which might be offered to the patients in the near future.

Naftopidil improves locomotor activity and urinary frequency in rats with pelvic venous congestion

The α1D/A receptor antagonist, naftopidil, inhibits micturition reflex by acting on various different sites. We examined the effects of naftopidil on bladder activity and changes in the induced urinary frequency using female rats with pelvic venous congestion (PC). Twenty-four female rats were divided into sham, PC, and PC/naftopidil groups. After anesthetizing rats in the PC and PC/naftopidil groups, the bilateral common iliac veins and uterine veins were ligated. Rats in the sham and PC groups were fed a standard diet, while rats in the PC/naftopidil group were fed diets containing 0.04% naftopidil. After 4 weeks of treatment, locomotor activity, urinary nitric oxide metabolites (NOx), continuous cystometry, and plasma monoamine measurements were performed. PC rats exhibited a decrease of locomotor activity, a shorter interval between bladder contractions on continuous cystometry, and decreased urinary NOx and plasma serotonin levels than the sham rats. The PC/naftopidil rats exhibited an increase of locomotor activity, a longer interval between bladder contractions, and increased urinary NOx and plasma serotonin levels. Therefore, naftopidil might improve bladder dysfunction induced by pelvic venous congestion due to several actions in the central nervous system and bladder tissue, as well as acting as an α1 blocker to cause pelvic venous dilation.

Spinal mechanism of micturition reflex inhibition by naftopidil in rats

AIM

We investigated the spinal mechanism through which naftopidil inhibits the micturition reflex by comparing the effects of noradrenaline and naftopidil in rats.

METHODS

The following were investigated: the influence of oral naftopidil on plasma monoamine and amino acid levels, the distribution of oral 14C-naftopidil, the effects of intravenous (IV) or intrathecal (IT) injection of noradrenaline or naftopidil on isovolumetric bladder contractions, amino acid levels in the lumbosacral spinal cord after IT noradrenaline or naftopidil, and the effects of IT naftopidil and strychnine and/or bicuculline on isovolumetric bladder contractions.

KEY FINDINGS

Oral naftopidil decreased the plasma adrenaline level, while it increased the serotonin and glycine levels. After oral administration, 14C-naftopidil was detected in the spinal cord and cerebrum, as well as in plasma and the prostate gland. When the bladder volume was below the threshold for isovolumetric reflex contractions, IV (0.1mg) or IT (0.1μg) noradrenaline evoked bladder contractions, but IV (1mg) or IT (0.01-1μg) naftopidil did not. When the bladder volume was above the threshold for isovolumetric reflex contractions, IV or IT noradrenaline transiently abolished bladder contractions. IT noradrenaline decreased the levels of glycine and gamma-aminobutyric acid (GABA) in the lumbosacral cord, while IT naftopidil increased the GABA level. IT strychnine and/or bicuculline blocked the inhibitory effect of IT naftopidil on bladder contractions.

SIGNIFICANCE

Naftopidil inhibits the micturition reflex by blocking α1 receptors, as well as by the activation of serotonergic, glycinergic, and GABAergic neurons in the central nervous system.

The role of naftopidil in the management of benign prostatic hyperplasia

Naftopidil, which to a certain extent shows an affinity to α1D-adrenoceptor subtype in addition to a high affinity to α1A-adrenoceptor, has been used for the treatment of benign prostatic obstruction and benign prostatic hyperplasia (BPH) associated lower urinary tract symptoms (LUTS). The aim of the present review is to systematically refer to the published studies on this unique agent for BPH. Based on a randomized prazosin-controlled study and another double-blind placebo-controlled study, which verified the dose-dependent effects of naftopidil, the Japanese Ministry of Health, Labor and Welfare approved naftopidil for treating men with BPH in 1996. Several tamsulosin-controlled studies have suggested treatment effects of naftopidil similar to those of tamsulosin and potentially higher efficacy for alleviating storage symptoms by naftopidil. Although well-designed, randomized studies are warranted to confirm the long-term outcomes and effector/target of naftopidil, the α1A-antagonist naftopidil, which also blocks α1D-adrenoceptor, improves voiding symptoms, and may also be useful for the management of men with storage symptoms represented by nocturia, retrieving their quality of life impaired by BPH-associated LUTS.

Naftopidil for the treatment of urinary symptoms in patients with benign prostatic hyperplasia

Naftopidil, approved only in Japan, is an α1-adrenergic receptor antagonist (α1-blocker) used to treat lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). Different from tamsulosin hydrochloride and silodosin, in that it has higher and extremely higher affinity respectively, for the α1A-adrenergic receptor subtype than for the α1D type, naftopidil has distinct characteristics because it has a three times greater affinity for the α1D-adrenergic receptor subtype than for the α1A subtype. Although well-designed large-scale randomized controlled studies are lacking and the optimal dosage of naftopidil is not always completely determined, previous reports from Japan have shown that naftopidil has superior efficacy to a placebo and comparable efficacy to other α1-blockers such as tamsulosin. On the other hand, the incidences of ejaculatory disorders and intraoperative floppy iris syndrome induced by naftopidil may be lower than for tamsulosin and silodosin having high affinity for the α1A-adrenergic receptor subtype. However, it remains unknown if the efficacy and safety of naftopidil in Japanese is applicable to white, black and Hispanic men having LUTS/BPH in western countries.

Clinical feature of men who benefit from dose escalation of naftopidil for lower urinary tract symptoms: a prospective study

Objectives. To examine the feature of men who benefit from dose escalation of naftopidil for lower urinary tract symptoms (LUTSs). Methods. Based on the IPSS, men reporting LUTS were prospectively studied using 50 mg/day of naftopidil for the first 4 weeks; satisfied patients continued its 50 mg/day (n = 11), and those reporting unsatisfactory improvement received its 75 mg/day (n = 35) for the next 4 weeks. Results. The 75 mg group showed improvement in the total IPSS and QOL score in a dose-dependent manner (at 4 weeks: P < .001, at 4 weeks versus 8 weeks: P < .05). In the 50 mg group, both scores reduced at 4 weeks, thereafter unchanged. The baseline slow stream score alone was higher in the 75 mg group (P = .013). The rate of change in the QOL score during the initial 4 weeks (ΔQOL) and Δnocturia was smaller in the 75 mg group (P < .05). Conclusions. Men with high slow stream score and unsatisfactory improvement in nocturia may benefit from dose escalation of naftopidil.

Naftopidil for the treatment of lower urinary tract symptoms compatible with benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is a common condition in aging men causing lower urinary tract symptoms (LUTS). Treatment aims are to relieve symptoms and prevent disease progression. Of the different alpha-1 adrenergic receptors (ARs) in the prostate, alpha-1a receptors are known to be central to prostatic smooth-muscle contraction. Recent studies have shown that patients with BPH may also have a predominance of alpha-1d receptors.

OBJECTIVES

To evaluate the efficacy and adverse effects of naftopidil, a selective alpha-1d oral alpha-blocking agent for the treatment of LUTS associated with BPH.

SEARCH STRATEGY

Systematic review of trials published January 1950 to January 2009. Sources included MEDLINE and bibliographies of retrieved articles and review articles.

SELECTION CRITERIA

Eligible trials included: men diagnosed with symptomatic BPH; compared Naftopidil to placebo, control, or combination therapy; evaluated clinically relevant outcomes between randomized groups; had at least 4-weeks follow up; and were published in English language.

DATA COLLECTION AND ANALYSIS

Participant demographics and comorbidities, enrollment criteria, outcomes, adverse events, numbers and reasons for dropouts were extracted onto standardized extraction forms by one reviewer. The mean change and per cent improvement from baseline in AUA (American Urological Association Symptom Score) and IPSS (International Prostate Symptom Score) scores and other efficacy outcomes for treatment and control groups were calculated. If feasible, the efficacy outcomes and adverse events data were pooled.

MAIN RESULTS

Eight trials were eligible (N = 744 participants). All trials were conducted in Japan. Study duration ranged from 4 to 17 weeks. The mean age of participants was 68 years; pretreatment mean IPSS = 17.8 and mean peak urine flow (Qmax) = 9.5 mL/s (milliliters/second). No trials compared naftopidil to placebo. In 5 trials (N = 419), naftopidil in doses of 25 to 75 mg/d (milligrams/day) showed a mean IPSS improvement similar to low-dose tamsulosin (0.2 mg/d) (8.4 versus 8.9 points). Compared to a phytotherapy preparation (eviprostat), naftopidil significantly improved total IPSS (-5.9 versus 0.4; P < 0.0002). In one trial, the addition of anticholinergic drugs (oxybutynin or propiverine hydrochloride) to naftopidil did not offer any significant improvement for IPSS or Qmax in comparison to treatment with naftopidil alone. Although IPSS did not significantly differ between high- (75 mg/d) and low-dose (25mg/d) naftopidil, high dose significantly improved Qmax compared to low dose (1.2 mL/s versus 0.2 mL/s). Adverse events reported were few, mild and similar to those seen with 0.2 mg/d tamsulosin.

AUTHORS' CONCLUSIONS

There are no data from placebo controlled trials regarding the efficacy of naftopidil in men with symptomatic BPH. Limited information suggests that treatment with naftopidil provides short-term improvement in urinary symptom-scale scores (total IPSS/AUA), QoL (quality of life) score, and urinary symptoms from baseline comparable to low-dose tamsulosin. Adverse effects due to naftopidil were few and usually mild.

Management of benign prostatic hyperplasia with silodosin

It has been reported that blockade of α1A-adrenoceptor (AR) relieves bladder outlet obstruction, while blockade of α1D-AR is believed to alleviate storage symptoms due to detrusor overactivity. Silodosin, (-)-1-(3-hydroxypropyl)-5-[(2R)-2-({2-[2-(2,2,2trifluoroethoxy) phenoxy]ethyl}amino)propyl]-2,3-dihydro-1H-indole-7- carboxamide, is a new α1A-AR selective antagonist. Silodosin is highly selective for the α1A-AR subtype, showing an affinity for the α1A-AR that is 583- and 55.5-fold higher than its affinity for the α1B-and α1D-ARs, respectively. In randomized, double-blind, placebo-controlled phase III studies performed in Japan and the United States, silodosin has been shown to be effective for both storage and voiding symptoms associated with benign prostatic hyperplasia. Early effects of silodosin (after 2-6 hours or day 1) on lower urinary tract symptoms have also been reported. In urodynamic studies, detrusor overactivity disappeared in 40% and improved in 35% of patients after administration. In pressure flow studies, the grade of obstruction on the International Continence Society nomogram showed improvement in 56% of patients. The rate of adverse events in the silodosin, tamsulosin and placebo groups was 88.6%, 82.3%, and 71.6%, respectively. The most common adverse event was (mostly mild) abnormal ejaculation (28.1%). However, few patients (2.8%) discontinued silodosin because of abnormal ejaculation. Orthostatic hypotension showed a similar incidence in the silodosin (2.6%) and placebo (1.5%) groups. In conclusion, silodosin improves detrusor overactivity and obstruction and thus may be effective for both storage and voiding symptoms in patients with benign prostatic hyperplasia.

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.

Change of expression levels of alpha1-adrenoceptor subtypes by administration of alpha1d-adrenoceptor-subtype-selective antagonist naftopidil in benign prostate hyperplasia patients

BACKGROUND

We examined whether the change of alpha(1)-adrenoceptor (alpha(1)-AR) subtype expression levels in the prostate occurred by administration of the alpha(1d)-AR-subtype-selective antagonist naftopidil to benign prostate hyperplasia (BPH) patients, and discussed the possible alternation of its effectiveness by the chronic administration of alpha(1)-AR antagonists.

METHODS

Fifteen patients with untreated BPH aged 58-76 (mean age, 68.2 +/- 7.4 years) underwent prostate biopsy from the transition zone before and after 50 mg naftopidil administration daily for 12 weeks. Taqman quantitative reverse transcription polymerase chain reaction was performed using these biopsy specimens to estimate the expression level of each alpha(1)-AR subtype. Comparison was made of the expression level of alpha(1)-AR subtypes before and after naftopidil administration. We also examined the correlation between the change of alpha(1)-AR subtype expression levels and the short-term efficacy of naftopidil.

RESULTS

Naftopidil administration for 12 weeks down-regulated the expression of alpha(1a)-AR and alpha(1b)-AR mRNA and up-regulated the expression of alpha(1d)-AR mRNA without a change in the total alpha(1)-AR mRNA expression level. There was no correlation between the change of alpha(1)-AR subtype expression levels and the short-term efficacy of naftopidil for BPH patients.

CONCLUSION

The change of alpha(1d)-AR expression level may be regarded as a compensatory adaptation to chronic alpha(1d)-AR antagonist naftopidil administration. This may mean that long-term use of the same alpha(1)-AR antagonist for BPH patients induces therapeutic tolerance.

Alpha1 Adrenoceptors in Human Urinary Tract: Expression, Distribution and Clinical Implications

Adrenergic receptors (ARs) are a class of proteins belonging to the G protein-coupled receptor family. Pharmacological and molecular studies allowed dividing ARs into three different categories: α1, α2 and β. In this review, we focused on α1 ARs and α1 AR antagonists, since α 1 ARs play an important role in the pathophysiology of a number of urinary tract (UT) dysfunctions. α1 ARs are widely expressed in human UT; in particular, the three ureter areas (distal, medial and proximal) show different patterns of receptor expression (i.e. distal > medial = proximal), giving the molecular basis for the use of α1 ARs antagonist in the expulsive therapy of distal ureter calculi. Bladder areas are characterized by important differences among trigone, detrusor and neck, the first showing a different pattern of expression compared to the other parts. Further, there are evidences of both density and subtype gender-dependent expressions. α1 ARs expression in prostate and detrusor is a widely investigated area of research, mainly due to the clinical impact of benign prostatic hyperplasia (BPH). Urethra has not been well studied in human, although it plays a role in the control of continence.

Studies carried out on α1 AR subtype expression in the UT indicate that, although the presence of each subtype is observed, α1A firstly and then α1D ARs seem to be more expressed than α1B ARs. Thus, drugs that demonstrate high α1A/D AR selectivity have drawn the researchers’ attention. As it relates specifically to the α1 AR antagonists used in the treatment of lower UT symptoms, the concept of uroselectivity has been operationally defined; indeed, in a number of recent publications uroselectivity has been defined as the degree to which a given compound inhibits norepinephrine-induced increase in urinary muscle contractions and/or its propensity to generate unwanted cardiovascular effects, such as decreases in blood pressure.

Ejaculatory disorder caused by alpha-1 adrenoceptor antagonists is not retrograde ejaculation but a loss of seminal emission

AIM

The etiology of the ejaculatory disorder induced by alpha-1 blockers is still controversial, although it has been suggested to be retrograde ejaculation. The aim of this study was to investigate the distribution of alpha-1 adrenoceptor subtype mRNA in human seminal vesicles, and to analyze the prevalence and etiology of the disorder in healthy men.

METHODS

Experimental Study. Seminal vesicles from 10 surgical specimens (eight radical prostatectomy, two radical cystectomy) were dissected. Real-time PCR was conducted for quantification of mRNA expression of each alpha-1 adrenoceptor subtype. Clinical Study. Ejaculatory disorder was investigated using 17 healthy male volunteers. Tamsulosin (0.2 mg and 0.4 mg) and naftopidil (50 mg and 100 mg) were administered in a crossover manner for 3 days. The ejaculatory volume, sperm count in midstream urine after ejaculation, and fructose concentration in seminal plasma were investigated.

RESULTS

Real-time PCR revealed that alpha-1a mRNA was significantly predominant in seminal vesicles (P < 0.001; 1a, 75.0%; 1b, 11.7%; 1d, 13.3%). Ejaculatory volume (baseline 2.72 +/- 0.28 mL) significantly decreased in the tamsulosin group (0.2 mg, 1.75 +/- 0.31 mL; 0.4 mg, 1.51 +/- 0.39 mL; P < 0.05), but not in the naftopidil group (50 mg, 2.70 +/- 0.24 mL; 100 mg, 2.48 +/- 0.26 mL; P = NS). There was no sperm in midstream urine after any ejaculation.

CONCLUSIONS

The current study demonstrates that alpha-1a mRNA is predominant among the adrenoceptor subtypes in human seminal vesicles. Decreased capacity of contraction of the seminal vesicles is proposed as the cause of the ejaculatory disorder induced by alpha-1 blockers.

Emerging drug therapies for benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is the nonmalignant enlargement of the prostate gland caused by increases in number of both epithelial and stromal cells. Clinically, BPH leads to voiding dysfunction, which is most often referred to as lower urinary tract symptoms (LUTS). Historically, the only treatments for LUTS due to BPH were watchful waiting or surgery (transurethral or open prostatectomy). However, over the last 20 years medical therapy has taken a prominent role in the management of BPH. Current medical treatments for BPH include alpha-adrenergic receptor antagonists, inhibitors of the 5-alpha reductase enzyme and various phytotherapies. These agents are generally effective and safe; however, many patients are unable to tolerate the side effects or are refractory to medical management and require surgery. In light of this, many potential new therapies for the treatment of BPH are under development. Some represent a variation of current treatments, whereas others target novel molecular pathways within the prostate. The aim of this review is to examine current pharmacotherapies as well as to highlight emerging drugs that may improve our treatment of patients with LUTS secondary to BPH.

Clinical efficacy of an alpha1A/D-adrenoceptor blocker (naftopidil) on overactive bladder symptoms in patients with benign prostatic hyperplasia

AIM

We evaluated the efficacy of an alpha1a/d blocker, naftopidil, on storage symptoms in patients with benign prostatic hyperplasia (BPH), using frequency/volume charts (FVC).

METHODS

A total of 81 patients with BPH (52-91 years, mean age 69.0 years) were studied. The inclusion criteria were: (i) one or more episode(s) of urinary urgency/day; (ii) a score of eight or more points on the International Prostate Symptom Score (I-PSS); and (iii) three or more points in any of the scores for three items (frequency, nocturia, and urgency) of the I-PSS. The patients received 50-75 mg/day of naftopidil for 6 weeks. All the patients were examined for 2-day FVC before and after the administration of naftopidil. I-PSS, quality of life index, and uroflowmetry were also evaluated.

RESULTS

Total I-PSS decreased from 19.1 to 10.5 points (P < 0.0001), with significant improvement of both storage and voiding symptom scores (P < 0.0001, both). The score for urgency decreased from 3.1 to 1.4 (P < 0.0001). Daytime and night-time frequency decreased from 9.3 to 8.0 (P < 0.0001) and from 2.7 to 2.0 (P = 0.0009), respectively. Mean volume/void increased from 174.0 to 188.6 mL (P = 0.0453). Nocturia decreased from 3.2 to 2.3 (P < 0.0001) in 40 patients who suffered from nocturia two times or more. Notably, significant improvement of nocturia was observed in the patients both with and without nocturnal polyuria (P = 0.0006 and 0.0135, respectively).

CONCLUSION

The alpha1a/d blocker naftopidil improves not only voiding symptoms but also storage symptoms, and is effective for nocturia in patients with BPH regardless of the existence of nocturnal polyuria.

Quantification of alpha1-adrenoceptor subtypes by real-time RT-PCR and correlation with age and prostate volume in benign prostatic hyperplasia patients

BACKGROUND

We used a real-time reverse transcriptase polymerase chain reaction (RT-PCR) method for quantification of each alpha(1)-adrenoceptor (alpha(1)-AR) subtype expression level, and examined whether age and prostate volume influence human prostate alpha(1)-AR subtype expression.

METHODS

Enrolled in our study were 75 men with lower urinary tract symptoms (LUTS) secondary to untreated benign prostatic hyperplasia (BPH). Real-time RT-PCR was performed using prostate biopsy specimens to quantify the expression level of each alpha(1)-AR subtype.

RESULTS

The median expression level (interquartile range) was 1.24 (0.66-2.32), 0.16 (0.10-0.33), and 1.11 (0.75-2.27) x 1,000 copies/beta-actin for alpha(1a)-, alpha(1b)-, and alpha(1d)-AR mRNA, respectively. The expression levels differed with the individual. The expression levels of alpha(1a)-AR, alpha(1d)-AR, and total alpha(1)-AR mRNA showed a significant positive correlation with patient age, but did not correlate with prostate volume.

CONCLUSION

The difference in the expression of the alpha(1)-AR subtype with the patient may be the cause of the difference in the effectiveness of several subtype-selective alpha(1)-AR antagonists from patient to patient. The increase of alpha(1)-AR mRNA expression level with age could be an important factor in the pathogenesis of clinically significant BPH.

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.

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.

Single-blind, randomized controlled study of the clinical and urodynamic effects of an alpha-blocker (naftopidil) and phytotherapy (eviprostat) in the treatment of benign prostatic hyperplasia

AIM

The aim of our study was to examine the efficacy of naftopidil in terms of the international prostate symptom score (IPSS) and urodynamic parameters in the treatment of benign prostatic hyperplasia (BPH). Eviprostat was used as a control to study the efficacy of naftopidil.

METHODS

Forty-nine patients with BPH (mean age 67.9 +/- 7.8 years) were involved in the study. Patients were randomly assigned either to the naftopidil group, which was treated with the alpha-blocker naftopidil (50-75 mg daily, 36 patients), or the eviprostat group, which was treated with phytotherapy (six tablets of eviprostat daily, 13 patients).

RESULTS

The mean total IPSS, the total storage and voiding symptom scores, and the quality of life score decreased significantly (P < 0.0001 for each variable) in the naftopidil group, but not in the eviprostat group. In the naftopidil group, analyses showed significant increases in average and maximum flow rate and bladder capacity at first desire to void (P < 0.001, P = 0.001 and P = 0.024, respectively), and significant decreases in the postvoid residual, the percent of residual and the Abrams-Griffiths number (P = 0.009, P = 0.008 and P = 0.042, respectively). However, in the eviprostat group, no significant changes were noted in terms of these symptomatic and urodynamic parameters. In the pressure/flow study, an improvement in the International Continence Society nomogram grade was noted in 29% of the naftopidil group, but in only 16% of the eviprostat group. Among the 14 patients in the naftopidil group, detrusor overactivity disappeared in 21% and cystometric capacity increased in 36%, but no improvement in detrusor overactivity was noted in the eviprostat group.

CONCLUSIONS

Naftopidil appears to have been effective in this short-term treatment of BPH.

α1-Adrenergic Receptors and Their Inhibitors in Lower Urinary Tract Symptoms and Benign Prostatic Hyperplasia

PURPOSE

We provide a comprehensive overview of the role of alpha1-adrenergic receptors (alpha1ARs) as critical mediators of lower urinary tract symptoms (LUTS) and pathophysiology in benign prostatic hyperplasia (BPH), and we review the pharmacological antagonists of alpha1ARs.

MATERIALS AND METHODS

A review was performed of pertinent studies in the literature relating to the pathophysiology of LUTS and BPH, focusing on the role of alpha1ARs, and of clinical trial and practice data evaluating the different agents that inhibit these receptors.

RESULTS

Further characterization of the alpha1AR gene family indicates that 3 receptor subtypes exist in humans. Their different distribution between urinary tract and cardiovascular tissues has provided a strategy for the development of improved therapeutic agents. Since excessive activity of the alpha1aAR and alpha1dAR subtypes appears to be a common feature in symptomatic BPH and alpha1aARs are enriched in prostatic tissue, drugs that demonstrate high alpha1aAR selectivity have attracted attention. Tamsulosin, which has high affinity for alpha1aAR and alpha1dAR subtypes but not for alpha1bAR, shows efficacy similar to the nonsubtype selective agents terazosin and doxazosin. It is associated with fewer cardiovascular side effects, although it has some ejaculatory side effects. The nonsubtype selective agent alfuzosin also demonstrates efficacy and offers an enhanced side effect profile, particularly minimizing hypotension. Other agents with super selective specificity for the alpha1aAR subtype are under investigation.

CONCLUSIONS

Further advances in the treatment of LUTS associated with BPH may depend not only on receptor subtype selectivity, but also on other pharmacokinetic and pharmacodynamic factors.

Influence of hypertension on lower urinary tract symptoms in benign prostatic hyperplasia

AIM

To clarify the influence of hypertension on lower urinary tract symptoms (LUTS) we examined the relationship between blood pressure, LUTS, and the effect of terazosin on LUTS in patients with benign prostatic hyperplasia (BPH).

METHODS

The subjects were patients who had LUTS and BPH. They were treated with terazosin (1 mg, twice-a-day) for 12 weeks. Calculation of the International Prostate Symptom Score (IPSS), measurement of blood pressure, and uroflowmetry were performed before and after 12 weeks of therapy. Patients were divided into a normotensive (NT) group and a hypertensive (HT) group at the time of first examination.

RESULTS

The IPSS for urinary frequency and nocturia in BPH-HT patients (n = 21; mean age, 71 years) were significantly higher than those in the BPH-NT patients (n = 21; mean age, 69 years) before the administration of terazosin. The total IPSS the BPH-HT patients was also significantly higher than that of the BPH-NT patients. There were no differences of uroflowmetric parameters between the two groups. After 12 weeks of therapy, systolic and diastolic blood pressure decreased in the BPH-HT patients, but not in the BPH-NT patients. However, the systolic pressure of the BPH-HT patients was still significantly higher than that of the BPH-NT patients. The score for each IPSS parameter decreased in both groups, but the difference of the score between the two groups increased.

CONCLUSION

Hypertension may worsen LUTS and may decrease the improvement of symptoms by terazosin.

Evidence-based meta-analysis of pharmacotherapy for benign prostatic hypertrophy

Evidence-based diagnosis and treatment have been proposed recently in various medical fields. Evidence-based diagnostic and therapeutic guidelines for benign prostatic hypertrophy (BPH), one of the most common urological diseases, have been proposed in foreign countries. This paper examines common therapeutic drugs for BPH in Japan from the viewpoint of evidence-based medicine (EBM). The term 'BPH' and drugs indicated for BPH were used as key words to search related articles in the PubMed website. A total of 813 articles extracted as of October 2001 were examined. The articles were ranked in levels ranging from I-V, where Level I indicated a large randomized controlled trial and Level V indicated a non-controlled case accumulation study. Among the 813 articles extracted, 132 clinical articles were suitable for evaluation. There were many reliable articles on the effectiveness of alpha-blockers. However, it seemed necessary to examine further how to choose the optimum alpha-blocker for each clinical case and the combination of antiandrogen drugs with alpha-blockers. It was also considered necessary to evaluate the effectiveness of drugs, such as eviprostat and hachimi-jio-gan, that are available only in Japan. The present study evaluated the effectiveness of commonly available therapeutic drugs for BPH in Japan from a viewpoint of EBM.

Naftopidil, a novel alpha1-adrenoceptor antagonist, displays selective inhibition of canine prostatic pressure and high affinity binding to cloned human alpha1-adrenoceptors

The pharmacological profiles of the alpha1-adrenoceptor antagonists naftopidil, tamsulosin and prazosin were studied in an anesthetized dog model that allowed the simultaneous assessment of their antagonist potency against phenylephrine-mediated increases in prostatic pressure and mean blood pressure. The intravenous administration of each of these compounds dose-dependently inhibited phenylephrine-induced increases in prostatic pressure and mean blood pressure. To further assess the ability of the three compounds to inhibit phenylephrine-induced responses, the doses required to produce a 50% inhibition of the phenylephrine-induced increases in prostatic and mean blood pressure and the selectivity index obtained from the ratio of those two doses were determined for each test compound. Forty minutes after the intravenous administration of naftopidil, the selectivity index was 3.76, and those of tamsulosin and prazosin were 1.23 and 0.61, respectively. These findings demonstrated that naftopidil selectively inhibited the phenylephrine-induced increase in prostatic pressure compared with mean blood pressure in the anesthetized dog model. The selectivity of naftopidil for prostatic pressure was the most potent among the test compounds. In addition, using cloned human alpha1-adrenoceptor subtypes, naftopidil was selective for the alpha1d-adrenoceptor with approximately 3- and 17-fold higher affinity than for the alpha1a- and alpha1b-adrenoceptor subtypes, respectively. The selectivity of naftopidil for prostatic pressure may be attributable to its high binding affinity for alpha1a- and alpha1d-adrenoceptor subtypes.