Expressions and mechanical functions of α1-adrenoceptor subtypes in hamster ureter

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.

Meta-Analysis of the Safety and Efficacy of α-Adrenergic Blockers for Pediatric Urolithiasis in the Distal Ureter

OBJECTIVE

Pediatric urolithiasis is a common condition, and medical expulsive therapy has grown to be accepted by many parents. We carried out a meta-analysis to identify the efficacy and safety of α-adrenergic blockers for the treatment of pediatric urolithiasis.

METHODS

We identified related articles from the PubMed, Embase, and Cochrane Library databases. All published randomized controlled trials (RCTs) describing the use of α-adrenergic blockers and placebo treatment for pediatric distal urolithiasis were involved. The outcomes included stone expulsion rate, stone expulsion time, pain episodes, need for analgesia, adverse events, and related subgroup analyses.

RESULTS

A total of nine RCTs were involved in our study, including 586 patients. We found that α-adrenergic blockers could significantly increase the rate of stone expulsion [odds ratio (OR), 3.49; 95% confidence interval (CI), 2.38-5.12; p < 0.00001], reduce the stone expulsion time [mean difference (MD), -5.15; 95% CI, -8.51 to -1.80; p = 0.003], and decrease pain episodes (MD, -1.02; 95% CI, -1.33 to -0.72; p < 0.00001) and analgesia demand (MD, -0.92; 95% CI, -1.32 to -0.53; p < 0.00001) but had a higher incidence of side effects (MD, 2.83; 95% CI, 1.55 to 5.15; p = 0.0007). During subgroup analyses, different medications (tamsulosin, doxazosin, and silodosin) also exhibited better efficiencies than placebo, except for doxazosin, which showed no difference in expulsion time (MD, -1.23; 95% CI, -2.98 to 0.51; p = 0.17). The three kinds of α-adrenergic blockers also appeared to be better tolerated, except for tamsulosin with its greater number of adverse events (MD, 2.85; 95% CI, 1.34 to 6.03; p = 0.006). Silodosin led to a better expulsion rate than tamsulosin (OR, 0.42; 95% CI, 0.20 to 0.92; p = 0.03). In addition, α-adrenergic blockers increased the stone expulsion rate regardless of stone size and decreased the expulsion time of stones measuring <5 mm (MD, -1.71; 95% CI, -2.91 to -0.52; p = 0.005), which was not the case for stones measuring >5 mm in expulsion time (MD, -3.61; 95% CI, -10.17 to 2.96; p = 0.28).

CONCLUSION

Our review suggests that α-adrenergic blockers are well-tolerated and efficient for treating pediatric distal urolithiasis. We also conclude that silodosin is the best choice of drug, offering a better expulsion rate, but it remains to be evaluated further by future studies.

The safety and efficacy of doxazosin in medical expulsion therapy for distal ureteric calculi: A meta-analysis

Purpose

Alpha-adrenergic receptor blockers can be effectively used in the context of medical expulsion therapy (MET) to treat ureteric stones. This study was designed to evaluate the safety and efficacy of doxazosin in MET relative to placebo or tamsulosin.

Methods

We systematically searched the PubMed, the Cochrane Library, EMBASE, Chinese Academic Database, and Web of Science databases to select randomized controlled trials (RCT) that compared the use of doxazosin with placebo or tamsulosin to treat ureteric stones. All patients we included were limited to those diagnosed with visible stones in the distal ureter. The diameter of ureteric stones does not exceed 10 mm.

Results

Eight trials comparing doxazosin with placebo or tamsulosin containing 667 patients were assessed in the final analysis. The meta-analysis showed that doxazosin effectively treated ureteric stones and was better than placebo in terms of efficacy. Relative to the placebo group, the expulsion rate of stones from the distal ureter (OR = 3.00, 95% CI [2.15, 4.19], I2 = 0%, P < 0.00001) was significantly increased, and the expulsion time (days) was shortened (mean difference) (MD) = −4.03, 95% CI [−4.53, −3.53], P < 0.00001). The doxazosin group experienced fewer pain episodes (MD = −0.78, CI = [−0.94, −0.23], I2 = 0%, P < 0.00001) than the placebo group. A subgroup analysis showed that the doxazosin group had a higher expulsion rate (of 5–10 mm stones) compared with the placebo group. Although doxazosin resulted in significantly more adverse effects compared with the placebo, the patient’s symptoms were mild and no further medical interventions were required. Moreover, the expulsion time (days) was shorter for patients receiving doxazosin (MD = −0.61, 95% CI [−0.97, −0.24], I² = 39%, P = 0.001) than those receiving tamsulosin.

Conclusion

Compared with the placebo group, patients receiving doxazosin had a greater expulsion rate, a reduced expulsion time, and fewer pain episodes. The expulsion time of doxazosin was shorter than that of tamsulosin.

Silodosin versus tamsulosin for medical expulsive treatment of ureteral stones: A systematic review and meta-analysis

Silodosin, a recently introduced selective α-blocker, has a much higher selectivity for the α-1A receptor. The efficacy and safety of silodosin compared to tamsulosin in medical expulsive therapy (MET) are controversial. The objective of this study was to assess the efficacy and safety of silodosin compared to tamsulosin for treating ureteral stones <10 mm in diameter. We systematically searched the PubMed, EMBASE, Cochrane library, and Scopus databases from their inception to May 2018. We included randomized controlled studies (RCTs) and observational studies, which investigated stone expulsion rates using silodosin compared to tamsulosin. Data were synthesized using a random-effects model. Sixteen studies with 1824 patients were eligible for inclusion. Silodosin achieved significantly higher expulsion rates than tamsulosin (pooled risk difference (RD): 0.13, 95% confidence interval (CI): 0.09 to 0.18, GRADE: high). A subgroup analyses showed that silodosin has a significantly higher expulsion rate on stone sizes of 5-10 mm than tamsulosin (pooled RD: 0.14, 95% CI: 0.06 to 0.22, I2 = 0%). The superior effect was not observed on stone sizes <5 mm. A multivariate regression showed that the RD was negatively associated with the control expulsion rate after adjusting for age and gender (coefficient -0.658, p = 0.01). A sensitivity analysis showed that our findings were robust. Patients receiving silodosin also probably had a significantly shorter expulsion time (pooled mean difference (MD): -2.55 days, 95% CI: -4.06 to -1.04, I2 = 85%, GRADE: moderate) and may have fewer pain episodes (pooled MD: -0.3, 95% CI: -0.51 to -0.09, GRADE: low) but a higher incidence of retrograde ejaculation by 5% compared to those receiving tamsulosin. In conclusion, compared to tamsulosin, silodosin provided significantly better stone passage for patients with ureteral stones (particularly for sizes of 5~10 mm), shorter expulsion times, and fewer pain episodes but caused a higher incidence of retrograde ejaculation.

Do Preoperative Alpha Blockers Facilitate Ureteroscope Insertion at the Vesico-Ureteric Junction? An Answer from a Prospective Case-Controlled Study

Objective: To evaluate whether alpha blockers facilitate the navigation of the ureteroscope through the ureteric orifice, if administered preoperatively, based on the role of alpha blockers, mainly tamsulosin, in medical expulsive therapy of ureteric calculus. Methods: A prospective, case-control study of 174 patients who underwent ureteroscopic stone removal for lower or mid ureteral calculi between November 2014 and March 2016 was carried out. We included patients >14 years of age who were planned for ureteroscopic stone removal. We divided the patients into two groups, including those who were not prescribed alpha blockers prior to surgery (Group A: no alpha blocker) and those patients who were started on alpha blockers, tamsulosin 0.4 mg, 3 days prior to surgery (Group B: alpha blocker). We excluded patients with stone size >1 cm, spontaneous stone passage prior to surgery, unable to perform ureteroscopy (URS), and previous history of ureteroscopic intervention. Results: Our study included 124 patients, among whom 60 patients were prescribed alpha blockers preoperatively (Group B). The mean age of the study population was 37.62+9.74 (15–64 years) and the mean stone burden was 38.92+8.21 (15.94–58.12 mm2). The difference in rate of ureteroscope negotiation through the ureteric orifice between Groups A and B was not statistically significant (p=0.57). Conclusions: In URS, preoperative administration of alpha blockers failed to improve technical ease and lower complication rate. Further large group, multi-centre studies are required todiscover a definitive role of alpha blockers prior to URS.

Efficacy and safety of silodosin in the medical expulsion therapy for distal ureteral calculi: a systematic review and meta-analysis

AIMS

Using a selective α-adrenoceptor blocker for medical expulsive therapy (MET) is an effective treatment approach widely used for ureteral stones. The aim of the review was to assess the efficacy and safety of silodosin in medical expulstion therapy compared with placebo and tamsulosin.

METHODS

A systematic search was performed in PubMed, Cochrane Library and Embase to identify randomized controlled trials that compared silodosin with a placebo or tamsulosin for ureteral calculi.

RESULTS

Eight publications involving a total of 1048 patients were used in the analysis, which compared silodosin with placebo and tamsulosin. We found that silodosin was effective in treating ureteral calculi in our meta-analysis and was superior to tamsulosin in its efficacy. The expulsion rate of all ureteral stones (OR 1.59, 95% CI 1.08, 2.36, P = 0.02), the expulsion rate of distal ureteral stones (OR 2.82, 95% CI 1.70, 4.67, P < 0.0001) and the expulsion time (days) of distal ureteral stones (standard mean difference (SMD) -4.71, 95% CI -6.60, -2.83, P < 0.00001) indicated that silodosin was more effective than the placebo. Moreover, expulsion rate (OR 2.54, 95% CI 1.70, 3.78, P < 0.00001), expulsion time (days) (SMD -2.64, 95% CI -3.64, -1.64, P < 0.00001) and pain episodes (P < 0.00001) indicated that silodosin was more effective than the tamsulosin. Even though silodosin had a significant increase in abnormal ejaculation compared with tamsulosin, no significant differences were observed for complications (OR 1.00, 95% CI 0.58, 1.74, P = 1.00).

CONCLUSIONS

This meta-analysis indicated that silodosin was superior to placebo or tamsulosin in the efficacy for distal ureteral calculi with better control of pain. The safety profile of silodosin was similar to tamsulosin though retrograde ejaculation was worse for silodosin use. We conclude that silodosin might have potential as a MET for ureteral stones.

Long-term prescription of α-blockers decrease the risk of recurrent urolithiasis needed for surgical intervention-a nationwide population-based study

Purpose

α1 receptors and subtypes have been confirmed to distribute in human pelvis and calyces recently. As used in ureteral stones, α-blocker treatment may facilitate kidney stone passage and long-term prescription of α-blocker may decrease the risk of recurrent urolithiasis. The aim of this study is to determine if use of α-blockers 180 days or more can decrease the risk of recurrent urolithiasis needed for surgical intervention.

Materials and Methods

A representative database of 1,000,000 patients from Taiwan’s National Health Insurance was analyzed. Eligible patients were those who had received the first-time procedure for upper urinary stone removal, including extracorporeal shock-wave lithotripsy, ureterorenoscopic lithotripsy, or both, between 2000 and 2010. After completing a 180-day treatment for first event, patients were prospectively followed-up until a second set of stone procedures was performed (proxy of stone recurrence), loss to follow-up, or end of study. The effect of percentage of total number of days of α-blocker use on need for second set of stone procedures within a post treatment 180-day follow-up period was analyzed by quartile. A nested case-control study was also performed.

Results

1,259 patients were eligible for final analyses. During 3,980 person-years follow-up, 167 patients had recurrent urolithiasis needed for surgical intervention. From first to fourth quartile of drug exposure, recurrence rates were 45.64, 47.19, 43.11, and 18.52 per 1,000 person-years. The adjusted hazard ratio was 0.46 (95% CI = 0.24 to 0.89) for the fourth quartile (vs. quartile 1). In the nested case-control study, adjusted ORs was 0.23 (95% CI = 0.10 to 0.53) in the fourth quartile (vs. quartile 1). The results remained similar even in patients categorized by cumulative defined daily dose (cDDD) quartiles and average cDDD per day quartiles.

Conclusion

Use of α-blockers for 180 days or more decrease the risk of recurrent urolithiasis needed for surgical intervention. In patients at higher risk of recurrent urolithiasis, long term prescription of α-blockers might help them prevent further surgical intervention.

α(1)-Adrenoceptors in the urinary tract

α(1)-Adrenoceptors have been identified and characterized extensively by functional, radioligand-binding, and molecular biological techniques. Molecular clones have been isolated for three α(1)-subtypes (α(1a), α(1b), and α(1d)), and these subtypes are also functionally characterized. α(1)-Adrenoceptors are present in the prostate, urethra, bladder (urothelium, smooth muscle, and afferent nerves), ureter, vas deferens, peripheral ganglia, nerve terminals, vascular tissues, and central nervous system (CNS), and they could all potentially influence overall urinary function and contribute to both the therapeutic and adverse effects of α(1)-adrenoceptor antagonists in patients with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). This review aimed to discuss the relevant physiological and pharmacological roles and molecular biology of α(1)-adrenoceptor subtypes in the prostate, urethra, bladder, ureter, and CNS.

Silodosin: an orally active selective α1-adrenoceptor antagonist for benign prostatic hyperplasia

α1-adrenoceptor antagonists play a central role in the treatment of uncomplicated symptomatic benign prostatic hyperplasia, frequently in combination with the 5-α-reductase inhibitors such as finasteride and dutasteride. Clinically useful examples include alfuzosin, doxazosin, tamsulosin and terazosin. These can be subdivided into nonselective (doxazosin and terazosin) and uroselective (alfuzosin and tamsulosin) agents. In general, these agents appear to be equieffective. However, they can be distinguished on the basis of their adverse event profiles. Such adverse events include those due to their vasodilatory effects (dizziness, orthostatic hypotension and rhinitis), genitourinary effects (ejaculatory dysfunction) and nonspecific effects (e.g., asthenia, malaise and gastrointestinal upset). A new α1A-adrenoceptor antagonist, silodosin, has recently been approved. In most ways, it is similar to tamsulosin in its pharmacodynamic effects in vitro and in vivo (in both animals and humans). Limited clinical trial data have shown silodosin to significantly improve lower urinary tract symptoms associated with benign prostatic hyperplasia and quality of life, with effects sustainable for at least 1 year. Its adverse-event profile reflects that seen with other uroselective α-adrenoceptor antagonists with the exception of a relatively high-incidence rate of ejaculatory dysfunction (22 vs 2% with tamsulosin and 28 vs 1% with placebo). This article reviews the preclinical and clinical data concerning silodosin and introduces the reader to this new drug for the treatment of benign prostatic hyperplasia.

Mechanical function and gene expression of alpha(1)-adrenoceptor subtypes in dog intravesical ureter

OBJECTIVES

To characterize the contractile functions and gene expression of the alpha(1)-adrenoceptor (AR) subtypes present in the dog intravesical ureter.

METHODS

In a functional study, alpha(1)-AR antagonists were evaluated against phenylephrine (alpha(1)-AR agonist)-induced contractions in dog isolated intravesical ureteral preparations. The quantitative expression of alpha(1)-AR subtype mRNA in this tissue was determined using real-time quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

In the isolated intravesical ureter, prazosin (nonselective alpha(1)-AR antagonist), silodosin (selective alpha(1A)-AR antagonist), naftopidil (selective alpha(1D)-AR antagonist), and BMY-7378 (selective alpha(1D)-AR antagonist) all shifted the concentration-contractile response curve for phenylephrine to the right. The rank order of potencies (pK(B) value) was silodosin (9.45 +/- 0.14), prazosin (8.16 +/- 0.08), naftopidil (7.39 +/- 0.19), and BMY-7378 (6.78 +/- 0.20). The alpha(1A)-AR antagonist silodosin was much more potent than the 2 alpha(1D)-AR antagonists. The rank order of mRNA expression levels among the alpha(1)-AR subtypes was alpha(1d) (72.68%), alpha(1a) (24.14%), and alpha(1b) (3.18%).

CONCLUSIONS

In the dog intravesical ureter, alpha(1A)-AR plays a major role in contraction, despite the prevalence of alpha(1D)-AR.