A prospective, randomized, open-label, parallel trial comparing the efficacy of α-blocker or 5α-reductase inhibitor withdrawal to continued combination therapy on the maintenance of lower urinary tract symptoms in men with benign prostatic hyperplasia.

BACKGROUND: It is uncertain how long combination therapy should be continued in patients with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). We investigated the withdrawal effects of α1-adrenergic receptor blocker (AB) or 5α-reductase inhibitor (5ARI) following successful combination therapy. METHODS: This prospective, randomized, open-label, parallel trial enrolled 222 patients with BPH/LUTS who showed at least a seven-point improvement in International Prostate Symptom Score-total (IPSS-T) and a ≥ 20% reduction in prostate volume (PV) following the initiation of combination therapy. Patients were randomized in a 1:1:1 ratio into continued-combination, AB-withdrawal, and 5ARI-withdrawal groups. IPSS, overactive bladder symptom score, EuroQol-five-dimensional questionnaire (EQ-5D-5L), EuroQol-visual analog scale (EQ-VAS), prostate volume (PV), maximal flow rate, postvoid residual urine (PVR), and prostate-specific antigen level were assessed every 6 months for 24 months. The predictors of IPSS-T deterioration were evaluated. RESULTS: At Month 24, IPSS-T deterioration (≥2 point) was observed in 20/72 (27.8%) and 19/72 (26.4%) patients in the AB- and 5ARI-withdrawal groups, respectively. Among them, 4/72 (5.6%) and 4/70 (5.7%) patients required readdition of the withdrawn drug (p = 0.868). In the continued combination group, EQ-VAS improved at Month 24 compared to baseline (p = 0.028). At Month 24, the AB-withdrawal group showed improvements in EQ-5D-5L, EQ-VAS, and PVR (all p < 0.005), while the 5ARI-withdrawal group showed improvement in IPSS-S (p = 0.011). Diabetes mellitus was associated with IPSS-T deterioration at Month 24 (p = 0.020). CONCLUSIONS: In patients with BPH/LUTS who are reluctant to continue combination therapy, AB or 5ARI withdrawal may be offered in men with improvement in IPSS-T by at least seven points and reduction in PV by at least 20%.

Association of alpha-1-adrenergic antagonist use with the risk of gout development in benign prostatic hyperplasia patients: a population-based cohort study.

BACKGROUND: Men are more likely to develop benign prostatic hyperplasia (BPH) and gout as they age. However, the role of alpha-1-adrenergic antagonists, the medication for BPH, in the development of gout is uncertain. OBJECTIVE: To investigate the effect of alpha-1-adrenergic antagonist use on the risk of developing gout in BPH patients. METHODS: Data of patients with newly diagnosed BPH were retrieved from Taiwan's 2000-2013 National Health Insurance Research Database (total number: 15,390 patients; 7,695 patients in each cohort). Propensity score matching was conducted according to age, comorbidities, medication history for cohorts that received or did not receive alpha-1-adrenergic antagonists. Hazard ratios (HRs) were assessed for gout development using Cox proportional hazards regression models. RESULTS: Use of alpha-1-adrenergic antagonists was not associated with gout development in BPH patients (HR = 0.92; 95% confidence interval [CI], 0.78-1.10; P = 0.35). However, after stratification according to the average number of days of alpha-1-adrenergic antagonist use per year, patients with an average of >300 days had a significantly higher risk of gout development than patients who did not receive alpha-1-adrenergic antagonists (adjusted HR = 1.57; 95% CI, 1.25-1.97; P < 0.001). Patients with more days of medication use per year had a higher risk of gout development than those with fewer days of medication use (P < 0.001). CONCLUSION: Patients who received more doses of alpha-1-adrenergic antagonists per year had a higher risk of developing gout. A causal proof of the role of alpha-1-adrenergic antagonists use in gout development should be analysed in future studies designed as double blind randomized controlled trials.

Silodosin versus Tamsulosin for Medical Expulsive Therapy of Ureteral Stones: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background and Objectives: This systematic review and meta-analysis of randomized controlled trials was performed to compare the therapeutic effects and safety profiles of silodosin and tamsulosin for medical expulsive therapy (MET) of ureteral stones. Materials and Methods: We searched PubMed, EMBASE, the Cochrane Library, and Web of Science to identify articles published before July 2022 that described randomized controlled trials comparing silodosin and tamsulosin for MET of ureteral stones. Endpoints were stone expulsion rate, stone expulsion time, and total complication rate. Results: In total, 14 studies were included in our analysis. The size of ureteral stones was <1 cm. Compared with tamsulosin, silodosin resulted in a significantly higher stone expulsion rate (p < 0.01, odds ratio (OR) = 2.42, 95% confidence interval (CI) = 1.91 to 3.06, I2 = 0%) and significantly shorter stone expulsion time (p < 0.01, mean difference = −3.04, 95% CI = −4.46 to −1.63, I2 = 89%). The total complication rate did not significantly differ between silodosin and tamsulosin (p = 0.33, OR = 1.15, 95% CI = 0.87 to 1.52, I2 = 7%). Conclusions: Compared with tamsulosin, silodosin resulted in significantly better expulsion of ureteral stones <1 cm. The total complication rate did not significantly differ between silodosin and tamsulosin. Thus, silodosin may be superior to tamsulosin for MET of ureter stones <1 cm.

Otorhinolaryngological adverse effects of urological drugs.

PURPOSE: To describe the otorhinolaryngological adverse effects of the main drugs used in urological practice. MATERIALS AND METHODS: A review of the scientific literature was performed using a combination of specific descriptors (side effect, adverse effect, scopolamine, sildenafil, tadalafil, vardenafil, oxybutynin, tolterodine, spironolactone, furosemide, hydrochlorothiazide, doxazosin, alfuzosin, terazosin, prazosin, tamsulosin, desmopressin) contained in publications until April 2020. Manuscripts written in English, Portuguese, and Spanish were manually selected from the title and abstract. The main drugs used in Urology were divided into five groups to describe their possible adverse effects: alpha-blockers, anticholinergics, diuretics, hormones, and phosphodiesterase inhibitors. RESULTS: The main drugs used in Urology may cause several otorhinolaryngological adverse effects. Dizziness was most common, but dry mouth, rhinitis, nasal congestion, epistaxis, hearing loss, tinnitus, and rhinorrhea were also reported and varies among drug classes. CONCLUSIONS: Most of the drugs used in urological practice have otorhinolaryngological adverse effects. Dizziness was most common, but dry mouth, rhinitis, nasal congestion, epistaxis, hearing loss, tinnitus, and rhinorrhea were also reported. Therefore, doctors must be aware of these adverse effects to improve adherence to the treatment and to minimize damage to the health of patients.

Preoperative Use of Alpha-1 Receptor Blockers in Male Patients Undergoing Extracorporeal Shock Wave Lithotripsy for a Ureteral Calculus.

In this retrospective single-center cohort study, we investigated the impact of preoperative use of an alpha-1 adrenergic receptor (AR) blocker on the outcome of single-session extracorporeal shock wave lithotripsy (SWL) in 193 male patients who underwent SWL for a single ureteral calculus between 2006 and 2016. We reviewed their medical records to obtain the data on the preoperative use of alpha-1 AR blockers. The primary outcome was treatment success after single-session SWL. We performed a multivariable logistic regression analysis adjusting for clinically important confounders to examine the association between preoperative use of alpha-1 AR blockers and the treatment success of SWL. Among the 193 patients, 15 (7.8%) were taking an alpha-1 AR blocker preoperatively. A multivariable analysis showed that preoperative use of an alpha-1 AR blocker was a significant negative predictor for treatment success of SWL (adjusted odds ratio 0.17; 95% confidence intervals, 0.04-0.74). Our findings suggest that the preoperative use of an alpha-1 AR blocker was a negative predictor of treatment success of SWL in male patients with a single ureteral calculus. Clinicians should pay more attention to the preoperative drug use in determining an appropriate stone therapy modality.

Inhibitory effects of silodosin on the bladder mechanosensitive afferent activities and their relation with bladder myogenic contractions in male rats with bladder outlet obstruction.

AIMS: We investigated the effects of silodosin, an α1A-adrenoceptor (AR) antagonist, on bladder function, especially on non-voiding contractions (NVCs), in a male rat model of bladder outlet obstruction (BOO) by evaluating cystometry (CMG) findings and bladder mechanosensitive single-unit afferent activities (SAAs), related with microcontractions, which may be similar with NVCs and to be of myogenic origin, in the rat model. METHODS: BOO was created by partial ligation of the posterior urethra. At 4 days after surgery for BOO, an osmotic pump filled with silodosin (0.12 mg/kg/day) or its vehicle was subcutaneously implanted. At 10 days after surgery, CMG and SAAs measurements were taken under conscious and urethane-anesthetized conditions, respectively. The SAAs of Aδ- and C-fibers, which were identified by electrical stimulation of the pelvic nerve and by bladder distention, and intravesical pressure were recorded during constant bladder-filling with saline. Microcontractions were divided into three phases: "ascending," "descending," and "stationary." RESULTS: The silodosin-treated group showed a smaller number of NVCs in CMG measurements and lower SAAs of both Aδ- and C-fibers than the vehicle-treated group during bladder-filling. Moreover, in the vehicle-treated groups, the SAAs of both fibers for the ascending phase of microcontractions were significantly higher than those for the other two phases. On the contrary, no significant change was found between any of these three phases in the silodosin-treated group. CONCLUSION: The present results suggest that silodosin inhibits the SAAs of mechanosensitive Aδ- and C-fibers at least partly due to suppressing myogenic bladder contractions in male BOO rats.

Efficacy and safety of PDE5-Is and α-1 blockers for treating lower ureteric stones or LUTS: a meta-analysis of RCTs.

BACKGROUND: Lower ureteric stones and lower urinary tract symptoms are common in urology.Drug treatment is one of standard therapy,but the efficacy was controversial.Thus we aimed to investigate the efficacy and safety of monotherapy or combination therapy of adrenoceptor1 blockers and phosphodiesterase5 inhibitors for treatment. METHODS: Randomized controlled trials up to November 2016 were retrieved from PubMed, the Cochrane Library, Web of Science and Embase. A total of 17 studies were included. We analyzed data through random or fixed effect models. The heterogeneity between studies was assessed by the I2 test statistic. RESULTS: As for lower ureter stones, our analysis demonstrated tadalafil had a significantly lower incidence of abnormal ejaculation than adrenoceptor1 blockers (2.31 95%CI 0.22to0.84, P = 0.01),while combination therapy had a higher expulsion rate (2.49 95%CI 1.44to4.29, P = 0.001) and shorter expulsion time (- 1.98 95%CI -3.08to0.88, P = 0.0004) than tamsulosin. As for lower urinary tract symptoms, our analysis indicated adrenoceptor1 blockers was more effective than phosphodiesterase5 inhibitors on decreasing International Prostate Symptom Score (1.96 95%CI 0.03to3.89, P = 0.05) and Post-Void Residual (9.41 95%CI 1.40to14.41, P = 0.02) and phosphodiesterase5 inhibitors showed a greater effect than adrenoceptor1 blockers on improving Erectile Dysfunction (2.23 95%CI 1.24to3.22, P<0.0001).Combination therapy had a significantly better effect on International Prostate Symptom Score (1.47 95%CI 1.25to1.69, P<0.0001), Maximum flow rate (0.87 95%CI 0.71to1.04, P<0.0001), Post-Void Residual (10.74 95%CI 3.53to17.96,P = 0.004) and Quality of life (0.59 95%CI 0.22to0.97, P = 0.002) but was associated with higher incidences of adverse events (3.40 95%CI 1.82to6.36, P = 0.0001) than adrenoceptor1 blockers. Combination therapy had a significantly better effect on International Prostate Symptom Score (4.19 95%CI 3.34to5.04, P<0.0001), Maximum flow rate (1.86 95%CI 1.32to2.39, P<0.0001), Post-Void Residual (22.58 95%CI 9.13to36.04, P = 0.001) and Quality of life (0.68 95%CI 0.37to1.00, P<0.0001) without higher incidences of adverse events than PDE5-Is. CONCLUSIONS: In conclusion, this meta-analysis suggested combination therapy had a best efficacy of therapy for lower ureteric stones or lower urinary tract symptoms correlated with benign prostatic hyperplasia than monotherapy. Adrenoceptor1 blockers was more effective than phosphodiesterase5 inhibitors on International Prostate Symptom Score and Post-Void Residual. Both monotherapy and combination therapy were safe.

Comparison of Silodosin and Naftopidil for Efficacy in the Treatment of Benign Prostatic Enlargement Complicated by Overactive Bladder: A Randomized, Prospective Study (SNIPER Study).

PURPOSE: We investigated the efficacy of 2 α1-blockers with different affinities for the α1-adrenoceptor subtypes silodosin and naftopidil in the treatment of benign prostatic enlargement complicated by overactive bladder. MATERIALS AND METHODS: This was a prospective, open label, randomized, multicenter study of 350 outpatients with untreated benign prostatic enlargement associated with urinary urgency at least once per week and an OABSS (Overactive Bladder Symptom Score) of 3 or greater. Patients were randomly assigned to receive silodosin 8 mg per day or naftopidil 75 mg per day. Changes in parameters from baseline to 4 and 12 weeks were assessed based on I-PSS (International Prostate Symptom Score), I-PSS quality of life, OABSS and voiding functions measured by uroflowmetry. RESULTS: On efficacy analysis a total of 314 patients were included in the 2 groups. No significant difference in adverse effects was observed between the groups. Mean I-PSS and I-PSS quality of life scores, and OABSS significantly improved in both groups. Statistically significantly greater improvement in the silodosin group than in the naftopidil group was observed in total OABSS (p = 0.03), I-PSS quality of life score (p = 0.005) and OABSS urgency score (p <0.001) at 12 weeks. In regard to voiding function the maximum urinary flow rate showed significant improvements in both groups but the change in the maximum flow rate in the silodosin group at 12 weeks was significantly greater than in the naftopidil group (3.6 vs 2.1 ml per second). CONCLUSIONS: Silodosin, a pure α1A-adrenoceptor blocker, showed greater improvement in overactive bladder symptoms along with the urinary flow rate in patients with benign prostatic enlargement complicated by overactive bladder compared to naftopidil, an α1D>A-adrenoceptor blocker.

Safety and efficacy of the combination of once-daily tadalafil and alpha-1 blocker in Japanese men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia: A randomized, placebo-controlled, cross-over study.

OBJECTIVES: To evaluate the safety and efficacy of tadalafil plus α1 -blocker combination therapy in Japanese patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. METHODS: The present multicenter, randomized, double-blind, placebo-controlled, two-period cross-over study compared the effects of tadalafil and a placebo added to ongoing α1 -blocker therapy. A total of 171 Japanese patients were randomized. RESULTS: Tadalafil combined with an α1 -blocker did not decrease blood pressure in the orthostatic test. The only statistically significant differences in vital signs between the combination and monotherapy groups were diastolic blood pressure and pulse (P = 0.0194 and 0.0313, respectively). However, these changes were not considered clinically meaningful. Treatment-related adverse events occurred in 28.1% (47/167) and 24.2% (39/161) of patients in the combination therapy and α1 -blocker monotherapy groups, respectively. Additionally, 56.7% (89/157) of patients preferred combination therapy to monotherapy, though this was not statistically significant (P = 0.0937). There was a statistically significant reduction in the International Prostate Symptom Score voiding subscore in the combination therapy group (P = 0.0442). CONCLUSIONS: Concurrent treatment with tadalafil and an α1 -blocker seems to be safe and well tolerated in Japanese patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. Adding tadalafil to baseline α1 -blocker therapy does not translate in adverse effects on the blood pressure. Patients tend to prefer combination therapy over monotherapy, and there seems to be a clinical benefit when using combination therapy.

[How to act when an alpha-blocker is associated with a potent inhibitor of CYP3A4]. / Conduite à tenir en cas d'association d'un alpha-bloquant et d'un inhibiteur puissant du cytochrome 3A4.

OBJECTIVE: Combination of alpha-blockers with potent CYP3A4 inhibitors is either contra-indicated or not recommended. We searched data supporting this classification and guiding prescribers when such an interaction occurs. METHODS: We analyzed reports published by the French agency for drug safety, reference books and performed search in databases of pharmacokinetics studies and case or case series related with these interactions. RESULTS: The classification of the potential severity of these interactions defined by the French agency for drug safety evolved over time. Our literature search did not identify any cases or case series reporting serious clinical consequences of such interactions and no pharmacoepidemiological studies on the association between alpha-blockers and inhibitors of CYP3A4. The content of the summaries of product characteristics indicate that the combination of ketoconazole with alfuzosin, silodosin and tamsulosin increases the area under the curve of the alpha-blocker 3 fold. CONCLUSION: Data demonstrating the clinical consequences of an association between alpha-blocker and a potent CYP3A4 inhibitor are lacking. The 3 fold increase of the area under the curve for alfuzosin, silodosin and tamsulosin associated with ketoconazole while the association with the two first is contra-indicated and is not recommended with the third raises questions. This lack of data leaves doctors and pharmacists in a situation of uncertainty on how to proceed when such an interaction occurs.

Combination therapy only shows short-term superiority over monotherapy on ureteral stent-related symptoms - outcome from a randomized controlled trial.

BACKGROUND: Controversy remains on the superiority of combination therapy over monotherapy on ureteral stent-related symptoms (SRSs). We tend to explore if there is a necessity of combination therapy. METHODS: One hundred cases of unilateral upper urinary tract calculi with stent insertion (pre and post flexible ureteroscopy) were randomized into 4 groups, given non-treatment, solifenacin, tamsulosin or combination respectively. Eight times of follow-ups were given after each insertion. RESULTS: SRSs released spontaneously within 4 days after insertion (p = 0.017) but then stay with no further improvement. Benefit of solifenacin on flank pain started showing after day4 (p = 0.002), which was comparable to that of tamsulosin and combination (p = 0.914 vs 0.195). Combination therapy showed superiority over both monotherapy before day4, but after then solifenacin and tamsulosin showed similar effectiveness with the combination therapy on both bladder pain (p = 0.229 vs 0.394) and urgency (p = 0.813 vs 0.974). No improvement on hematuria or frequency was observed in each group. CONCLUSIONS: Combination therapy takes effect faster but shows no supervisory after the first few days compared with monotherapy. TRIAL REGISTRATION: The study protocol was registered on Chinese Clinical Trial Register on April 17th, 2013 (registration number: ChiCTR-TRC-13003148 ).

Non-inferiority of silodosin 4 mg once daily to twice daily for storage symptoms score evaluated by the International Prostate Symptom Score in Japanese patients with benign prostatic hyperplasia: a multicenter, randomized, parallel-group study.

OBJECTIVES: To compare the effect of treatment with silodosin 4 mg once daily versus that of silodosin 4 mg twice daily on storage symptoms in Japanese patients with benign prostatic hyperplasia. METHODS: A prospective, multicenter, 12-week, open-labeled study randomized a total of 268 men aged 50 years or older with benign prostatic hyperplasia and overactive bladder to silodosin 4 mg/day or 8 mg/day. Changes in the end-points of the average value of International Prostate Symptom Score, quality of life index in the International Prostate Symptom Score, Overactive Bladder Symptom Score and urodynamic parameters were evaluated. The change in the storage symptom subtotal score of the International Prostate Symptom Score was considered as the primary end-point. RESULTS: Silodosin 4 mg/day was not inferior to silodosin 8 mg/day in regard to the primary end-point. In contrast, the efficacy of treatment with silodosin 4 mg twice daily was greater than that of 4 mg once daily, based on both the quality of life index and the Overactive Bladder Symptom Score total score. There was a discrepancy between the scores evaluated using the International Prostate Symptom Score and Overactive Bladder Symptom Score questionnaires. CONCLUSIONS: Silodosin 4 mg once daily is not inferior to silodosin 4 mg twice daily in regard to storage symptoms score evaluated by the International Prostate Symptom Score. In contrast, silodosin 4 mg twice daily is more effective on storage symptoms evaluated by the Overactive Bladder Symptom Score than silodosin 4 mg once daily.

Effects of silodosin, a selective α1A-adrenoceptor antagonist, on bladder blood flow and bladder function in a rat model of atherosclerosis induced chronic bladder ischemia without bladder outlet obstruction.

PURPOSE: We investigated the effects of the selective α1A-adrenoceptor antagonist silodosin on bladder blood flow and bladder function in a rat model of atherosclerosis induced chronic bladder ischemia without bladder outlet obstruction. MATERIALS AND METHODS: The chronic bladder ischemia model was prepared by creating balloon endothelial injury of the bilateral iliac arteries in male rats. Using an osmotic pump, chronic bladder ischemia rats received silodosin subcutaneously at a rate of 0.1 or 0.3 mg/kg per day, or vehicle for 8 weeks. All groups received a 2% cholesterol diet throughout the experiment. For each α1-adrenoceptor subtype mRNA expression in bladder microvessels was examined by in situ hybridization. Bladder blood flow was measured using a laser speckle blood flow imager. Malondialdehyde in bladder tissue and 8-hydroxy-2'-deoxyguanosine in urine were measured as markers of oxidative stress. A metabolic cage study and cystometry were performed in conscious rats. RESULTS: The expression of all α1-adrenoceptor subtype mRNA was observed in rat bladder microvessels. Silodosin abrogated the decreased bladder blood flow in the empty bladder and during bladder distention that were evident in rats with chronic bladder ischemia. Levels of oxidative stress markers in these rats were significantly decreased by silodosin administration. Silodosin ameliorated bladder dysfunction in rats with chronic bladder ischemia in the metabolic cage study and on cystometry. CONCLUSIONS: Results suggest that in ischemic conditions α1-adrenoceptor antagonists such as silodosin may improve bladder function by restoring bladder blood flow.

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.

Differential Effects of Alpha 1-Adrenoceptor Antagonists on the Postsynaptic Sensitivity: Using Slice Patch-Clamp Technique for Inhibitory Postsynaptic Current in Substantia Gelatinosa Neurons From Lumbosacral Spinal Cord in Rats.

PURPOSE: Alpha1-adrenoceptors participate in improving storage symptoms of male lower urinary tract symptoms. However, the mechanism of action of these compounds remains unclear. The goal of the present study was to clarify the effect of α1- adrenoceptor antagonists on γ-aminobutyric acid (GABA)/glycine-mediated outward currents of the inhibitory postsynaptic current (IPSC) in substantia gelatinosa (SG) neurons from the lumbosacral spinal cord in rats. METHODS: Male adult Sprague-Dawley rats were used. Blind whole-cell patch-clamp recordings were performed in SG neurons from isolated spinal cord slice preparations. IPSCs were recorded in individual SG neurons to which naftopidil (100µM), tamsulosin (100µM), silodosin (30µM), or prazosin (10µM) were applied sequentially with intervening washout periods. Strychnine (2µM), bicuculline (10µM), or tetrodotoxin (TTX)(1µM) were added before naftopidil. Individual outward currents were analyzed. RESULTS: The bath application of naftopidil, yielded outward IPSCs in 13 of 52 SG neurons. The naftopidil response was unchanged in the presence of TTX. Regression analysis of the outward currents between the 1st and 2nd applications of naftopidil revealed a Pearson correlation coefficient of 0.996 with a line slope of 0.983. The naftopidil-induced outward current was attenuated in the presence of strychnine and/or bicuculline. The GABA/glycine-mediated outward currents induced by tamsulosin, silodosin, and prazosin were smaller than those obtained with naftopidil. CONCLUSION: Naftopidil-induced GABA/glycine-mediated outward currents in a subset of SG neurons prepared from the L6- S1 level of rat spinal cord. The results indicated that α1-adrenoceptor antagonists, particularly naftopidil, induce neural suppression (in part) by mediating hyperpolarization. The response is associated with glycinergic and/or GABAergic neural transmission. Naftopidil may suppress the micturition reflex and improve urinary storage symptoms as a subsidiary effect resulting from hyperpolarization in SG neurons of the spinal cord.

Effect of Alpha 1-Adrnoceptor Antagonists on Postsynaptic Sensitivity in Substantia Gelatinosa Neurons From Lumbosacral Spinal Cord in Rats Using Slice Patch-Clamp Technique for mEPSC.

PURPOSE: Alpha1-adrenoceptors participate in improving storage symptoms of male lower urinary tract symptoms (LUTS). However, the mechanism of action of these compounds remains unclear. To clarify the mechanism of the α1-adrenoceptor antagonists, the amplitude of miniature excitatory postsynaptic currents (mEPSCs) was analyzed in the lumbosacral spinal cord in rats. METHODS: Male adult Sprague-Dawley rats were used. Blind whole-cell patch-clamp recordings were performed on substantia gelatinosa (SG) neurons in spinal cord slice preparations. The amplitude of mEPSCs was recorded in individual SG neurons to which α1-adrenoceptors (100µM naftopidil, 100µM tamsulosin, and 30µM silodosin) were applied sequentially with intervening washout periods. Individual amplitudes were analyzed. RESULTS: Pearson correlation coefficients (r) for the amplitudes of mEPSCs between the baseline and postadministration of α1- adrenoceptor antagonists indicated changes of the amplitude ranked in the order of naftopidil (r =0.393), tamsulosin (r=0.738), and silodosin (r=0.944). Together, the α1-adrenoceptor antagonists yielded significant increases in the amplitude of mEPSCs in SG neurons (n=108, P=0.012). However, the effects of each α1-adrenoceptor antagonist on the amplitude were as follows (relative to the baseline; n=36 each): naftopidil, P=0.129; tamsulosin, P=0.201; and silodosin, P=0.005. The rate of response to naftopidil for the outward current was relatively high among the α1-adrenoceptor blockers. An inward current was observed only with the naftopidil application. CONCLUSION: Alpha1-adrenoceptor antagonists changed the amplitudes of mEPSCs in a subset of SG neurons in slices prepared from the L6-S1 levels of rat spine. Although the α1-adrenoceptor antagonists generated inward or outward currents in the SG neurons, different rates of response were observed with each antagonist. These results are important for understanding the mechanisms of action (at the spinal level) of α1-adrenoceptor antagonists for the storage symptoms of male LUTS.

Expression of bladder α1-adrenoceptor subtype after relief of partial bladder outlet obstruction in a rat model.

Purpose: Many patients with benign prostatic hyperplasia require treatment for persistent storage symptoms, even when the obstruction is successfully relieved by surgery. Previous studies identified a characteristic increase in α1D-adrenoceptor levels in the bladder in a bladder outlet obstruction (BOO) model. Here, we investigated the expression of α1-adrenoceptor subtypes in the bladder after relief of partial BOO (pBOO) in a rat model. Materials and Methods: A total of 60 female Sprague-Dawley rats were randomly divided into three groups (sham-operated, pBOO, and pBOO relief groups), and the expression of α1-adrenoceptor subtypes in the urothelium and detrusor muscle tissues was examined by western blot. Results: The expression of the α1D-adrenoceptor was significantly higher in the urothelium and detrusor muscle tissue of the pBOO and pBOO relief groups than in the corresponding tissue of the sham-operated group. Additionally, the α1A-adrenoceptor was predominant in the sham-operated group but significantly decreased in the urothelium in the pBOO group. No significant differences were found in α1A-adrenoceptor levels in detrusor muscle or whole bladder. Conclusions: Our results showed that α1D-adrenoceptor levels were consistently increased with pBOO, even after relief, suggesting that the α1D-adrenoceptor might be a cause of persistent storage symptoms after relief of pBOO.

Alpha Blocker and 5-Alpha Reductase Inhibitor Prescribing Habits among Urologists and Primary Care Physicians.

INTRODUCTION: While primary care physicians often prescribe medical therapy for voiding symptoms attributed to benign prostate enlargement, it is not clear to what extent they use novel or varied agents. We describe alpha blocker and 5-alpha reductase inhibitor prescribing habits of primary care physicians and compare them with those of urologists. METHODS: Within Medicare Part D we identified providers who prescribed alpha blockers and 5-alpha reductase inhibitors in 2015. We determined the proportions that prescribed 1 versus multiple agents, different types of agents and both types of medications, and compared them between providers. RESULTS: Overall 94% (9,327) of urologists, 50% (54,253) of internal medicine physicians and 61% (60,063) of family medicine physicians prescribed an alpha blocker in 2015. Urologists were more likely to prescribe multiple alpha blockers. However, they were also more likely to predominantly use a single agent. A higher percentage of urologists prescribed newer agents (alfuzosin, silodosin) while a higher percentage of primary care physicians prescribed older agents (terazosin, doxazosin). For 5-alpha reductase inhibitors 87.5% (8,692) of urologists, 32.0% (34,598) of internal medicine physicians and 34.4% (33,720) of family medicine physicians issued prescriptions. Urologists were more likely to prescribe a single 5-alpha reductase inhibitor predominantly and prescribe multiple 5-alpha reductase inhibitors. More primary care physicians prescribed alpha blockers without also prescribing 5-alpha reductase inhibitors. CONCLUSIONS: Most primary care physicians prescribed alpha blockers to Medicare beneficiaries. Urologists were more likely to use diverse as well as newer agents, signaling greater awareness of medical options, although also more complex cases. Urologists were more likely to habitually prescribe single medications. As primary care physicians are involved in the initial treatment of these patients, further education regarding medical options and appropriate indications should be considered.