Beta 3 Adrenoreceptor Agonist for the Management of Lower Urinary Tract Symptoms in Men With Benign Prostatic Hyperplasia: A Systematic Review

Risks and side effects in the medical management of benign prostatic hyperplasia

Benign prostatic hyperplasia affects up to 80% of men in their lifetime. It causes bladder outflow obstruction, leading to lower urinary tract symptoms, which can have a large impact on quality of life. Lifestyle modifications and pharmacotherapy are often offered as first-line treatments for patients. These include alpha blockers, 5-alpha-reductase inhibitors, phosphodiesterase-5 inhibitors, anticholinergics, B3-agonists, and desmopressin. While often well tolerated, these pharmacotherapies do have significant side effects, which both clinicians and patients should understand and discuss in order to make an informed treatment decision among alternatives. The purpose of this review is to provide a current overview of the risks and side effects of commonly used medications in benign prostatic hyperplasia management.

Novel pharmacotherapeutic avenues for bladder storage dysfunction in men

INTRODUCTION

Bladder storage dysfunction is associated with low quality of life in men and remains a challenging field in pharmacotherapy because of low persistence followed by patient-perceived lack of efficacy and adverse effects. The persistent desire for the development of novel pharmacotherapy is evident, leading to numerous research efforts based on its pathophysiology.

AREAS COVERED

This review describes the pathophysiology, current pharmacotherapeutic strategies, and emerging novel drugs for male bladder storage dysfunction. The section on emerging pharmacotherapy provides an overview of current research, focusing on high-potential target molecules, particularly those being evaluated in ongoing clinical trials.

EXPERT OPINION

As pharmacotherapies targeting alpha-adrenergic, beta-adrenergic, and muscarinic receptors - the current primary targets for treating male bladder storage dysfunction - have demonstrated insufficient efficacy and side effects, researchers are exploring various alternative molecular targets. Numerous targets have been identified as central to regulating bladder afferent nerve activity, and their pharmacological effects and potential have been evaluated in animal-based experiments. However, there is a limited number of clinical trials for these new pharmacotherapies, and they have not demonstrated clear superiority over current treatments. Further research is needed to develop new effective pharmacotherapies for bladder storage dysfunction in men.

Inside the Biology of the β3-Adrenoceptor

Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic activities, such as thermogenesis and lipolysis in brown and white adipose tissue, respectively (BAT, WAT), negative inotropic effects in cardiomyocytes, and relaxation of the blood vessels and the urinary bladder. The β3-AR has been suggested as a potential target for cancer treatment, both in adult and pediatric tumors, since under hypoxia its upregulation in the tumor microenvironment (TME) regulates stromal cell differentiation, tumor growth and metastases, signifying that its agonism/antagonism could be useful for clinical benefits. Promising results in cancer research have proposed the β3-AR being targeted for the treatment of many conditions, with some drugs, at present, undergoing phase II and III clinical trials. In this review, we report the scientific journey followed by the research from the β3-Ars' discovery, with focus on the β3-Ars' role in cancer initiation and progression that elects it an intriguing target for novel antineoplastic approaches. The overview highlights the great potential of the β3-AR, both in physiologic and pathologic conditions, with the intention to display the possible benefits of β3-AR modulation in cancer reality.

Pharmacological Approaches in Managing Symptomatic Relief of Benign Prostatic Hyperplasia: A Comprehensive Review

Benign Prostatic Hyperplasia (BPH) is a prevalent condition that affects aging men, leading to the development of lower urinary tract symptoms (LUTS) and potentially severe complications such as complete obstruction. The management of BPH typically involves the use of medications from different classes, including alpha-1 antagonists, 5-alpha reductase inhibitors, and anticholinergics. Combination therapy utilizing drugs from different classes can also effectively manage the BPH-LUTS complex. Recent research has revealed that phosphodiesterase 5 (PDE5) inhibitors, including Tadalafil and Sildenafil, are highly effective in treating LUTS associated with BPH. Tadalafil as a monotherapy has recently been shown to significantly improve LUTS in BPH patients. Additionally, the use of herbal remedies as a treatment option for BPH has also been widely debated. Previous research suggests that saw palmetto can reduce BPH symptoms through several proposed mechanisms, but recent trials have found inconsistencies in its efficacy. In this literature review, we conducted an extensive PubMed database search to provide current and comprehensive insights into BPH treatment options. This review comprehensively evaluates available treatments for managing BPH, highlighting the effectiveness of different classes of medications and combination therapies in managing associated symptoms. The present investigation also discusses recent research on the efficacy of PDE5 inhibitors in treating LUTS associated with BPH and the uncertain efficacy of herbal remedies. The insights provided by this study can guide healthcare professionals in making informed decisions about managing BPH, ultimately improving patient outcomes.

Comparative Study Between Behavior Therapy and Behavior Therapy Plus Mirabegron 50 mg in Sexually Active Men With Bothersome Overactive Bladder Symptoms - A Multicenter, Randomized Study

PURPOSE

We evaluated the therapeutic effects on overactive bladder (OAB) symptoms and sexual function of behavioral therapy with or without mirabegron in sexually active male patients with OAB. Mirabegron, a selective β3 adrenoceptor agonist for the treatment of OAB, has been shown to induce corpus cavernosum relaxation.

METHODS

In this 4-site, randomized controlled trial, 150 sexually active men with OAB were enrolled between June 2020 and May 2022. Participants were randomly allocated (1:2) into 2 treatment groups: (1) behavioral therapy alone (n = 50) and (2) a combination of mirabegron 50 mg daily and behavioral therapy (n = 100). The evaluation was based on the overactive bladder symptoms score (OABSS), the International Index of Erectile Function, the ejaculatory domain short form, the International Prostate Symptom Score, patient perception of bladder condition, quality of life, and urodynamic parameters. The therapeutic outcomes were assessed at baseline, 4 weeks, and 12 weeks.

RESULTS

There were 65 patients (65%) in the combination subgroup and 36 patients in the behavioral therapy who completed all 12 weeks of treatment. Both groups had a statistically significant improvement in OABSS after 12 weeks of treatment. The combination therapy group achieved a statistically significant improvement in all 4 subscores of OABSS, however, the urinary frequency (P = 0.120) and urinary incontinence (P = 0.234) subscores in the behavioral therapy only group did not show a significant change. Additionally, the combination group had a significant improvement in functional bladder capacity, which was not seen in the behavioral therapy group. However, both groups did not have a significant change in erectile or ejaculatory function.

CONCLUSION

Behavioral therapy combined with mirabegron had more significant impact on the improvement of OAB than behavior therapy alone. However, both groups did not have significant changes in erectile or ejaculatory function.