α1-Blockers in Men with Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Obstruction: Is Silodosin Different?

Effect of α1D-adrenoceptor blocker for the reduction of ureteral contractions

PURPOSE

Urolithiasis is a common urinary tract disease with growing prevalence. Alpha1-adrenoceptors (α1-ARs) are abundant in ureteral smooth muscle, distributed with different α1-AR subtypes. α1D-AR is the most widely distributed in the ureter. However, the effect of α1D-AR blockade on ureteric contraction remains unknown.

MATERIALS AND METHODS

We dissected smooth muscle tissues (3 mm×3 mm) from the rat bladder and human ureter, tied silk strips on both tissue ends, and measured contraction in an organ bath chamber. Contraction activity in ureteral smooth muscle cells (USMCs) was immunocytochemically examined using primary rat and human USMC cultures.

RESULTS

Using the organ bath system, we determined the inhibitory effects of silodosin, tamsulosin, and naftopidil. Naftopidil significantly decreased contractility of rat bladder tissue; similar results were observed in human ureteral tissue. To confirm ex vivo experimental results in vitro , we examined the phosphorylation of myosin light chain (MLC), a marker of contractility, in a primary human USMC culture. The examined drugs decreased phospho-MLC levels in human USMCs; however, naftopidil profoundly increased MLC dephosphorylation.

CONCLUSIONS

We studied the effects of naftopidil, an α1D-AR inhibitor, on the ureter. Compared with alpha-blockers, naftopidil significantly relaxed ureteral smooth muscle. Therefore, naftopidil could be an effective therapy for patients with ureteral stones.

Pharmacotherapeutic options in the treatment of nocturia: update on current oral drug therapies

INTRODUCTION

Nocturia is a common urinary complaint among patients presenting with lower urinary tract symptoms and in recent years, there is a greater emphasis to tailor the treatment for nocturia in a more holistic and multidisciplinary manner given the potential multifactorial causes for nocturia.

AREAS COVERED

Current oral drug therapies can be classified into three main groups, namely, decreasing polyuria, targeting bladder capacity, and improving sleep-wake and circadian rhythm. The authors focus this article on these oral therapies and provide their expert opinion.

EXPERT OPINION

Treatment strategies should always involve lifestyle changes and behavioral modifications, with the targeted treatment of underlying medical conditions that may cause nocturia. Desmopressin remains the only drug approved specifically for the treatment of nocturia. Medications targeting the bladder and prostate can have secondary benefits in minimizing nocturnal frequency and urgency especially if the drug is taken at nighttime. Treatment of an underlying sleep disorder or circadian disorder can often help to increase total sleep time and quality, and perhaps reducing the nocturnal diuresis and nocturia episodes. Future studies in nocturia should improve the identification and diagnosis of underlying mechanisms that lead to nocturia, so treatment can become more streamlined, while at the same time, explore the role of various pharmacotherapeutic agents and novel therapy to reduce or eliminate nocturia.

Managing Nocturia in Frail Older Adults

This review discusses the available evidence in the current evaluation and treatment of nocturia in frail older adults. No evidence specifically evaluates the use of behavioral interventions in the treatment of the frail older adult with nocturia, but their use is supported in other cohorts. Behavioral modifications and optimal management of comorbidities remain the first-line treatment for all age groups and should be emphasized in the frail due to their favorable safety profile. No studies specific to the frail older adult support the use of pharmacotherapy. Some evidence exists for the efficacy of several agents in the older adult; however, this is difficult to extrapolate to the frail, and safety concerns abound. Desmopressin may be effective in the older adult, but a high risk of hyponatremia raises concerns for its safety, and therefore it is not recommended in the frail. α-Antagonists may have limited efficacy in men with known benign prostatic hyperplasia (BPH); they are relatively well tolerated, although the risk of orthostatic hypotension in the frail should be considered. β3-agonist trials suggest limited clinical utility. Antimuscarinics are not found to be useful in this cohort and are contraindicated in the frail older adult given the ability of antimuscarinics to cause cognitive impairment, delirium, and falls. No data examine the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in the frail older adult. Additionally, the American Geriatrics Society Beers Criteria recommends against the use of muscarinics in those over the age of 75 years and therefore their use is not supported.

Can We Clinically Distinguish Anejaculation From Retrograde Ejaculation in Patients on α1A-Blockers Therapy for Lower Urinary Tract Symptoms?

OBJECTIVE

To investigate the physiopathology of ejaculatory disorders (EjD) and discriminate between retrograde ejaculation (REj) and anejaculation (AEj) induced by α1A-blockers, through the association between the mean postorgasm seminal vesicle volume and the presence of sperm in midstream urine, in patients with moderate-to-severe lower urinary tract symptoms (LUTS) secondary to benign prostatic enlargement.

MATERIALS AND METHODS

Therapy-naïve male patients with LUTS and without previous EjD were treated with α1A-blockers. Pre- and post-treatment EjD were investigated through question 4 of the 4-item Male Sexual Function questionnaire and the Male Sexual Health Questionnaire for Ejaculatory Dysfunction Short Form (MSHQ-EjD-SF). After 12 weeks, postorgasm urine was collected for sperm count and seminal vesicle volume was calculated through transrectal ultrasound.

RESULTS

All 42 patients reported with EjD after treatment with α1A-blockers: 4-item Male Sexual Function questionnaire and MSHQ-EjD-SF Q4 scores were significantly higher (P <.001) and MSHQ-EjD-SF Q1-3 score was significantly lower (P <.001) than before. Postorgasm seminal vesicle volume was significantly higher in patients with postorgasm sperm-negative urine (AEj), and lower in patients with postorgasm sperm-positive urine (REj; P <.001).

CONCLUSION

We clearly demonstrated an association between the presence of sperm in the midstream urine and seminal vesicle volume after orgasm, strongly confirming and differentiating the hypothesis of a dual etiology for EjD (REj vs AEj) secondary to α1A-blockers therapy for LUTS.

Pharmacotherapy for Nocturia

Purpose of Review

To assess current pharmacological principles used for treatment of nocturia/nocturnal polyuria.

Recent Findings

The pathophysiology of nocturia is often multifactorial, but two main mechanisms have been identified, occurring alone or in combination: low functional bladder capacity and nocturnal polyuria. The multifactorial pathophysiology not only implies several possible targets for therapeutic intervention but also means that it is unlikely that one treatment modality including drugs will be successful in all patients. Drugs approved for the treatment of male LUTS and male and female OAB are known to be far more effective for treatment of the daytime symptoms than for nocturia.

Summary

Several pharmacological principles have been tested with varying success. The treatment of choice should depend upon the main underlying cause, thus aiming primarily to increase bladder capacity by counteracting detrusor overactivity and/or reducing nocturnal polyuria. Using current available agents, effective, personalized treatment should be designed taking into account gender, co-morbidities, and identified etiological factors. However, there is a medical need for new, approved drugs for treatments for patients with nocturia.

Benign Prostatic Obstruction Relief in Patients with Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Enlargement Undergoing Endoscopic Surgical Procedures or Therapy with Alpha-Blockers: A Review of Urodynamic Studies

Benign prostatic obstruction (BPO) contributes to the genesis of lower urinary tract symptoms as well as to pathologic remodeling of the lower and upper urinary tract in patients with benign prostate enlargement. Urodynamic studies demonstrate that both medical therapy with alpha-blockers (ABs) and endoscopic surgical procedures provide BPO relief. However, the magnitude of improvement is higher after surgery. Among ABs, silodosin is associated with the highest improvement of bladder outlet obstruction index (BOOI). A complex relationship exists between BOOI improvement and variations of both maximum urinary flow (Q _max) and detrusor pressure. When the reduction of BOOI is small, the improvement of Q _max is clinically irrelevant and the BOOI is mainly influenced by a decrease of detrusor pressure. In contrast, when the magnitude of BOOI reduction is robust, a meaningful improvement of both detrusor pressure and urinary flow is evident. When clustering ABs according to their receptor pharmacologic selectivity and urodynamic efficacy, three subgroups can be identified,with silodosin being the only member of a subgroup characterized by the highest levels of BOOI improvement and α-1A/α-1B receptor affinity ratio.