Use of sympathetic alpha antagonists in the management of pediatric urologic disorders

The use of alpha-adrenergic antagonists in pediatric nephrolithiasis: a systematic review

Objective

To evaluate existing clinical evidence for the efficacy of alpha blockers in the management of pediatric stone disease.

Methods

We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Cohort and randomized control trials of patients less than 18 years old with kidney stones managed with alpha-adrenergic antagonists were included. Outcomes included stone expulsion time, stone passage rate, mean number of pain episodes, and mean need for analgesics. We performed data extraction of the selected articles, and results were assimilated and synthesized qualitatively. Data extraction and risk of bias assessment was conducted by two independent reviewers.

Results

Of 257 relevant studies, 9 studies with 1,039 patients were included. Six studies measured stone expulsion time, with 5 studies noting statistically significant decreases in stone expulsion time for the treatment group compared to the control. Seven studies measured the stone expulsion rate, and 5 reported a statistically significant increased expulsion rate in the treatment group. Four studies reported a decrease in the mean number of pain episodes in the treatment group and two studies showed a decreased analgesic requirement compared to control. Two studies found alpha blockers not superior to watchful waiting after shock wave lithotripsy. Risk of bias was high in some studies, primarily due to incomplete reporting on methodology and study design.

Conclusions

Alpha blockers are supported by a growing body of evidence to be effective against nephrolithiasis in children, however large-scale, well-designed studies are needed to confirm these findings.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=330068, PROSPERO (CRD42022330068).

Neurogenic Lower Urinary Tract Dysfunction

Neurogenic lower urinary tract dysfunction (NLUTD) remains a formidable challenge to pediatric urologists to achieve the goals of renal preservation and the reduction of urinary tract infections as well as the attainment of continence and independence as children grow toward adulthood. Tremendous progress has occurred over the past 50 years which have witnessed an evolution in focus from mere survival to optimal quality of life. This review presents four separate guidelines for the medical and surgical care of pediatric NLUTD, most commonly related to spina bifida, to highlight the change in approach from expectant to more proactive management.

Silodosin in the treatment of distal ureteric stones in children: A prospective, randomised, placebo-controlled study

Objectives

To evaluate the possible role of silodosin (a highly selective α_1A-adrenoceptor antagonist) in facilitating the passage of distal ureteric stones (DUS) in children, as the role of α-blockers as medical expulsive therapy is well known in adults.

Patients and methods

In all, 40 paediatric patients (27 boys and 13 girls) diagnosed with unilateral, single, radiopaque DUS of <10 mm were included in the study. Their mean (SD, range) age was 8.1 (2.7, 5–17) years. The patients were randomly divided into two groups: Group A, received silodosin 4 mg as a single bedtime dose; and Group B, received placebo as a single bedtime dose. Ibuprofen was prescribed to both groups on-demand for pain episode relief. Patients were followed up biweekly for 4 weeks. The stone expulsion time and rate, pain episodes, analgesic use, and any adverse effects were recorded.

Results

The mean (SD) stone size in Group A was 6.6 (1.7) mm and in Group B was 6.7 (1.4) mm (P = 0.4). Two patients were lost to follow-up (one from each group), and one patient in Group A refused to complete the study. The stone-free rate at end of the 4-week treatment period was 88.8% in Group A vs 73.6% in Group B (P = 0.4). The mean (SD) stone expulsion time was 7.0 (4.3) vs 10.4 (4.7) days in groups A and B, respectively (P = 0.02). The mean (SD) number of pain episodes requiring ibuprofen was 2.3 (1.4) vs 4.7 (2.6) episodes in groups A and B, respectively (P < 0.001). Adverse effects (headache and dizziness) were recorded in three patients (16.7%) in Group A, which were mild and none of them discontinued treatment, whilst no adverse effects were recorded in Group B.

Conclusions

The data in the present study show that silodosin can be safely used in the treatment of DUS in children for decreasing time to stone expulsion, pain episodes, and analgesic requirement.

The efficacy and safety of adrenergic alpha-antagonists in treatment of distal ureteral stones in pediatric patients: A systematic review and meta-analysis

OBJECTIVE

We carried out a systematic review and meta-analysis to evaluate the efficacy and safety of adrenergic alpha-antagonists as a medical expulsive therapy for ureteral stones in pediatric patients.

METHODS

The PubMed, EMBASE and Cochrane Controlled Trials Register databases were searched up to January 2016. All randomized controlled trials and all cohort studies in which patients were randomized to receive either adrenergic alpha-antagonists or placebo for ureteral stones were identified. The outcome measures assessed were overall stone expulsion rate (primary), expulsion time (secondary), and treatment-emergent adverse events.

RESULTS

Five trials with a total of 406 pediatric patients met the inclusion criteria. According to the doses of adrenergic alpha-antagonists, the pooling effects of adrenergic alpha-antagonists were analyzed, with a higher expulsion rate obtained than in controls, the stone expulsion rate (OR=2.70, 95% CI 1.49 to 4.91, P=0.001). Adrenergic alpha-antagonists statistically did not significantly decrease the number of the stone expulsion time with the placebo, the stone expulsion time (SMD=-4.65, 95% CI -9.76 to 0.45, P=0.07). Safety assessments included common treatment-emergent adverse events (TEAEs) (OR=2.01, 95% CI 0.74 to 5.48, P=0.17). Compared with placebos, there was a higher stone expulsion rate with the adrenergic alpha-antagonists; in addition, fewer adverse effects were observed.

CONCLUSIONS

This meta-analysis may suggest that adrenergic alpha-antagonists are a safe and effective medical expulsive therapy choice for ureteral stones in pediatric patients. As the level of classification of evidence-based medicine, the level of evidence of our article is Ia. But it remains to need a large-scale multicenter randomized controlled study to be further confirmed.

LEVEL OF EVIDENCE

The level of evidence of our study is V.

Young rats exhibit an age- and sex-dependent bladder response to alpha-antagonists but not beta-agonists

INTRODUCTION

Previous studies have suggested that the onset of alpha- (α) and beta- (β) adrenergic receptor activity is delayed in young animals. The use of alpha1- (α1-) antagonists for dysfunctional voiding, and beta3- (β3-) agonists for overactive bladder in younger children may not be indicated if maturation is required before bladder and urethral adrenergic receptors are active.

OBJECTIVE

To determine the sex- and age-dependent responses of the bladder and external urethral sphincter (EUS) to α- and β-adrenergic agents in neonatal and young adult rats.

MATERIALS AND METHODS

A total of 72 naïve Sprague-Dawley rats (36 female, 36 male) and 15 bladder-reduced (BR) female Sprague-Dawley rats underwent cystometry and EUS electromyography at 3, 6, and 9 weeks of life. Following administration of WAY 100,635 (0.3 mg/kg, serotonergic receptor antagonist), the non-selective α-agonist phenylephrine (0.3 mg/kg), α-antagonist phentolamine (1-3 mg/kg), β-agonist isoprenaline (3 mg/kg) and β-antagonist propranolol (3 mg/kg) were delivered intravenously. The maximum intravesical pressure (IVP), pressure threshold (PT), intermicturition interval (IMI), contraction duration (CD), burst amplitude and burst frequency were compared after each drug.

RESULTS

The α-antagonist phentolamine lowered the IVP in 9-week-old males without lowering the PT. In contrast, the β-agonist isoprenaline lowered the IVP in both males and females of all ages, also without affecting the PT. Isoprenaline was also effective at shortening the CD in females, suggesting more effective bladder emptying. The α-agonist phenylephrine increased the IVP in 3-week-old and 6-week-old females and 3-week-old males, but this effect was blocked by pretreatment with phentolamine. The β-antagonist propranolol increased the PT in both males and females, and shortened the IMI in females, which was consistent with retention. Phenylephrine increased the burst duration in 9-week-old naïve females, while isoprenaline increased the burst amplitude and duration in 9-week-old BR females.

CONCLUSIONS

In the neonatal rat, both α- and β-adrenergic receptors actively regulate bladder function by 3 weeks of life, but the desired effect of decreasing IVP by α-antagonists was delayed until 9 weeks in male rats. In contrast, β-agonists were effective at decreasing IVP in both male and female rats of all ages, which suggests that they are better agents for enhancing bladder emptying in female and young male rats.

Medical expulsive treatment in pediatric urolithiasis

The frequency of stone disease in childhood ranges between 0.1-5 percent. Stone disease occurs as a result of enviromental, metabolic, anatomical, infectious and nutritional factors. Percutaneous nephrolitotomy, uretherorenoscopy, laparoscopic surgery, open surgery and extracorporeal shock wave lithothripsy are treatment alternatives for stone disease during childhood. However, these methods are not completely innocent. Some complications may occur after these procedures. These procedures are generally not cost- effective. Even invasive procedures have high success rates, so medical expulsive treatment modalities have become an alternative for a group of patients. Nonsteroidal anti- inflammatory drugs, antimuscarinic drugs, phospodiesterase type 5 inhibitors, steroids, calcium channel blockers and alpha blockers are treatment alterneatives used for this modality in the literature. The drug is chosen according to the location, size, and composition of the stone, recent technology, cost, surgeon's experience and surgeon's and the parents' preferences. In this review article the following topics will be discussed such as "Why medical expulsive treatment is needed during childhood? Which drug should be chosen for which stone type? How long should a treatment of urolithiasis last?

Tamsulosin for the management of distal ureteral stones in children: a prospective randomized study

PURPOSE

Based on efficacy demonstrated in the adult population, tamsulosin was evaluated with regard to facilitating ureteral stone expulsion in children presenting with distal ureteric calculi.

PATIENTS AND METHODS

A prospective randomized controlled study involving 61 children with distal ureteric calculi <12 mm was performed. The children were randomly divided into two groups. Group I (study group, n = 33) received tamsulosin and standard analgesia, and Group II (placebo group, n = 28) received standard analgesia and placebo. Patients were offered a closely monitored trial for spontaneous stone passage in the 4-week period prior to definitive therapy. The stone expulsion rate, number and duration of pain episodes, need for analgesia and possible side effects of medications were observed.

RESULTS

All patients completed the study and none were excluded due to side effects. No significant differences were found between the groups for age, gender and stone size. Mean patient age was 8.1 ± 6.8 years. There were 25 females and 36 males. The stone-free rate was 87.8% in Group I (29/33), compared with 64.2% (18/28) in Group II. A mean stone expulsion time of 8.2 and 14.5 days was recorded for Group I and II respectively, and this difference was statistically significant (P < 0.001).

CONCLUSIONS

Medical expulsion therapy for lower ureteric stones is a successful procedure in children. Tamsulosin demonstrated no clinically significant adverse effect, while proving to be a safe and effective treatment option.

Placebo-controlled trials in pediatric urology: a cautionary view from an ethical perspective

The ethical dispute regarding placebo-controlled trials is discussed in this review. Important issues, such as clinical equipoise, fiduciary obligation and middle ground theory, are examined in the context of pediatric urology clinical research. After reviewing the literature, the authors summarize specific indications for placebo-controlled trials in pediatric urology, and emphasize that physicians have ethical and moral obligations to patients, in the sense that one should carefully plan and conduct such trials in order to gain clinically important information without exposing children to undue risks.

Pediatric stone disease

Urinary stone disease is less common in children than adults. Although many aspects of pediatric stone disease are similar to that of adults, there are unique concerns regarding the presentation, diagnosis, and management of stone disease in children. We present a review of the increasing prevalence of pediatric stone disease, the diagnostic concerns specific to children, recent results from pediatric series regarding the expectant management and surgical treatment of stones, metabolic evaluation, and current research on the genetics of nephrolithiasis.