Cardiovascular effects of antimuscarinic agents in overactive bladder

Management of use of urinary antimuscarinics and alpha blockers for benign prostatic hyperplasia in older adults at risk of falls: a clinical review

PURPOSE

We aimed to outline the existing information and the underlying mechanisms of risk of falls associated with the use of urinary antimuscarinics for overactive bladder (OAB) or alpha-blockers for benign prostatic hyperplasia (BPH) in older adults. In addition, we aimed to provide assistance to clinicians in decision-making about (de-)prescribing these drugs in older adults.

METHODOLOGY

Based on a literature search in PubMed and Google Scholar, we reviewed the literature, and identified additional relevant articles from reference lists, with an emphasis on the most commonly prescribed drugs in OAB and BPH in older patients. We discussed the use of bladder antimuscarinics and alpha-blockers, their potential side effects related to falls, and the deprescribing of these drugs in older adults.

RESULTS

Urinary urgency or incontinence and lower urinary tract symptoms due to untreated OAB and BPH contribute to fall risk. On the other hand, the use of bladder antimuscarinics and alpha-blockers is also related to fall risk. They contribute to (or cause) falling through dizziness, somnolence, visual impairment, and orthostatic hypotension while they differ in their side-effect profiles regarding these problems. Falls are common and can cause a remarkable amount of morbidity and mortality. Thus, preventive measures should be taken to lower the risk. If the clinical condition allows, withdrawal of bladder antimuscarinics and alpha-blockers is recommended in fall-prone older adults. There are practical resources and algorithms that guide and assist clinicians in deprescribing these drug groups.

CONCLUSIONS

The decision to prescribe or deprescribe these treatments in patients at high risk of falls should be individualized. In addition to explicit tools that are helpful for clinical decision-making in (de-)prescribing these drugs, STOPPFall (a recently developed expert-based decision aid specifically aiming to prevent falls) is present to assist prescribers in attaining decisions.

Personalised 3D-Printed Mucoadhesive Gastroretentive Hydrophilic Matrices for Managing Overactive Bladder (OAB)

Overactive bladder (OAB) is a symptomatic complex condition characterised by frequent urinary urgency, nocturia, and urinary incontinence with or without urgency. Gabapentin is an effective treatment for OAB, but its narrow absorption window is a concern, as it is preferentially absorbed from the upper small intestine, resulting in poor bioavailability. We aimed to develop an extended release, intragastric floating system to overcome this drawback. For this purpose, plasticiser-free filaments of PEO (polyethylene oxide) and the drug (gabapentin) were developed using hot melt extrusion. The filaments were extruded successfully with 98% drug loading, possessed good mechanical properties, and successfully produced printed tablets using fused deposition modelling (FDM). Tablets were printed with varying shell numbers and infill density to investigate their floating capacity. Among the seven matrix tablet formulations, F2 (2 shells, 0% infill) showed the highest floating time, i.e., more than 10 h. The drug release rates fell as the infill density and shell number increased. However, F2 was the best performing formulation in terms of floating and release and was chosen for in vivo (pharmacokinetic) studies. The pharmacokinetic findings exhibit improved gabapentin absorption compared to the control (oral solution). Overall, it can be concluded that 3D printing technology is an easy-to-use approach which demonstrated its benefits in developing medicines based on a mucoadhesive gastroretentive strategy, improving the absorption of gabapentin with potential for the improved management of OAB.

Effects of vibegron on ambulatory blood pressure in patients with overactive bladder: results from a double-blind, placebo-controlled trial

OBJECTIVES

To characterize the blood pressure (BP) profile of the new β3-adrenergic receptor agonist, vibegron, in patients with overactive bladder.

METHODS

Patients were randomized to once-daily vibegron 75 mg or placebo for 28 days and underwent ambulatory BP monitoring. The primary endpoint was change from baseline (CFB) to day 28 in mean daytime ambulatory systolic BP (SBP). Secondary endpoints were CFB in mean 24-h SBP and in mean daytime and mean 24-h ambulatory diastolic BP (DBP) and heart rate (HR). Safety was assessed through adverse event reporting.

RESULTS

Of 214 patients randomized, 96 receiving vibegron and 101 receiving placebo had evaluable baseline and day 28 measurements. Overall, 39.6 and 30.7% of patients receiving vibegron and placebo, respectively, had preexisting hypertension. The least squares mean difference (LSMD; 90% confidence interval) between vibegron and placebo in CFB in mean daytime SBP was 0.8 (-0.9, 2.5) mmHg. LSMD in CFB in mean daytime DBP and HR was 0.0 mmHg and 0.9 bpm, respectively. No significant differences between treatments were seen in CFB in mean 24-h SBP (LSMD, 0.6 mmHg), DBP (-0.2 mmHg) or HR (1.0 bpm). The most common treatment-emergent adverse event was hypertension, with rates comparable between groups [vibegron: n = 5 (4.7%); placebo: n = 4 (3.7%)]. One patient receiving vibegron took a prohibited medication (phentermine) known to increase BP.

CONCLUSIONS

Once-daily vibegron had no statistically significant or clinically relevant effects on BP or HR.

Antimuscarinic use among older adults with dementia and overactive bladder: a Medicare beneficiaries study

OBJECTIVES

This study examined the incidence and predictors of antimuscarinic medication use including non-selective antimuscarinics among older adults with dementia and overactive bladder (OAB).

METHODS

The study used a new-user cohort design involving older adults (≥65 years) with dementia and OAB based on 2013-2015 Medicare data. Antimuscarinics included non-selective (oxybutynin, tolterodine, trospium, fesoterodine) and selective (solifenacin, darifenacin) medications. Descriptive statistics and multivariable logistic regression models were used to determine the incidence and predictors of new antimuscarinic use including non-selective antimuscarinics, respectively.

RESULTS

Of the 3.38 million Medicare beneficiaries with dementia, over one million (1.05) had OAB (31.03%). Of those, 287,612 (27.39%) were reported as prevalent antimuscarinics users. After applying continuous eligibility criteria, 21,848 (10.34%) incident antimuscarinic users were identified (77.6% non-selective; 22.4% selective). Most frequently reported antimuscarinics were oxybutynin (56.3%) and solifenacin (21.4%). Multivariable analysis revealed that patients ≥75 years, of black race, and those with schizophrenia, epilepsy, delirium, and Elixhauser's score were less likely to initiate antimuscarinics. Women, those with abnormal involuntary movements, bipolar disorder, gastroesophageal reflux disease, insomnia, irritable bowel syndrome, muscle spasm/low back pain, neuropathic pain, benign prostatic hyperplasia, falls/fractures, myasthenia gravis, narrow-angle glaucoma, Parkinson's disease, syncope, urinary tract infection and vulvovaginitis were more likely to initiate antimuscarinics. Further, patients with muscle spasms/low back pain, benign prostatic hyperplasia and those taking higher level anticholinergics had lower odds of receiving non-selective antimuscarinics, whereas white patients, black patients and those with schizophrenia and delirium were more likely to receive them.

CONCLUSIONS

Nearly one-third of dementia patients had OAB and over one-fourth of them used antimuscarinics. Majority of the incident users were prescribed non-selective antimuscarinics with several demographic and clinical factors contributing to their use. Given the high prevalence of OAB among dementia patients, there is a need to optimize their antimuscarinic use, considering their vulnerability for anticholinergic adverse effects.

Risk of Mortality Associated with Non-selective Antimuscarinic medications in Older Adults with Dementia: a Retrospective Study

BACKGROUND

Selective antimuscarinics may offer a favorable safety profile over non-selective antimuscarinics for the management of overactive bladder (OAB) in patients with dementia.

OBJECTIVE

To test the hypothesis that non-selective antimuscarinics are associated with increased risk of mortality compared to selective antimuscarinics in older adults with dementia and OAB.

DESIGN

Propensity score-matched retrospective new-user cohort design among Medicare beneficiaries in community settings.

PATIENTS

Older adults with dementia and OAB with incident antimuscarinic use.

MAIN MEASURES

The primary exposure was antimuscarinic medications classified as non-selective (oxybutynin, tolterodine, trospium, fesoterodine) and selective (solifenacin, darifenacin) agents. All-cause mortality within 180 days of incident antimuscarinic use formed the outcome measure. New users of non-selective and selective antimuscarinics were matched on propensity scores using the Greedy 5 → 1 matching technique. Cox proportional-hazards model stratified on matched pairs was used to evaluate the risk of mortality associated with the use of non-selective versus selective antimuscarinics in the sample.

KEY RESULTS

The study identified 16,955 (77.6%) non-selective antimuscarinic users and 4893 (22.4%) selective antimuscarinic users. Propensity score matching yielded 4862 patients in each group. The unadjusted mortality rate at 180 days was 2.6% (126) for non-selective and 1.6% (78) for selective antimuscarinic users in the matched cohort (p value < 0.01). The Cox model stratified on matched pairs found 50% higher risk of 180-day mortality with non-selective antimuscarinics as compared to selective ones (hazard ratio (HR) 1.50; 95% confidence interval (CI) 1.04-2.16). The study findings remained consistent across multiple sensitivity analyses.

CONCLUSIONS

Use of non-selective antimuscarinics was associated with a 50% increase in mortality risk among older adults with dementia and OAB. Given the safety concerns regarding non-selective antimuscarinic agents, there is a significant need to optimize their use in the management of OAB for older patients with dementia.

Is imidafenacin an alternative to current antimuscarinic drugs for patients with overactive bladder syndrome?

PURPOSE

Previous studies have included a limited number of randomized controlled trials (RCTs) and compared limited parameters after treatment with imidafenacin and other anticholinergic drugs (ADs) for overactive bladder syndrome (OAB), and controversy about the superiority of these ADs still remains. We aim to update the evidence and provide better clinical guidance.

METHODS

A systematic search of PubMed, Embase, ClinicalTrial.gov and Cochrane Library Central Register of Controlled Trials was conducted from January 2007 to April 2019. Meta-analysis of all published RCTs comparing imidafenacin with other ADs in patients with OAB was performed. The primary outcomes were the changes in OAB symptoms and OAB symptom score (OABSS). Secondary outcomes included adverse events (AEs) and the dropout rate related to AEs.

RESULTS

A total of 6 studies including 7 RCTs involving 1430 patients with mean follow-up of 23.43 weeks were included. All ADs improved OAB symptoms. Regarding efficacy, these drugs had similar efficacy in voids, urgency episodes, urgency incontinence episodes, incontinence episodes and OABSS. However, imidafenacin performed better in the reduction of nocturia episodes (MD = -0.24, 95% CI -0.44 to -0.04, P = 0.02). Moreover, imidafenacin was associated with a statistically lower dry mouth rate (RR = 0.87, 95% CI 0.75-1.00, P = 0.04), lower constipation rate (RR = 0.68, 95% CI 0.50-0.93, P = 0.01) and lower AE-related withdrawal rate (RR = 0.51, 95% CI 0.29-0.89, P = 0.02). There was no significant difference in terms of other complications.

CONCLUSIONS

In conclusion, imidafenacin was comparable to other ADs in the treatment of OAB. Moreover, imidafenacin presented a lower dry mouth rate, lower constipation rate and higher adherence and persistence.

Overactive Bladder is a Distress Symptom in Heart Failure

The prevalence of Heart failure (HF) is expected to increase worldwide with the aging population trend. The numerous symptoms of and repeated hospitalizations for HF negatively affect the patient’s quality of life and increase the patient’s economic burden. Up to 50% of patients with HF suffer from urinary incontinence (UI) and an overactive bladder (OAB). However, there are limited data about the relationship between UI, OAB, and HF. The association between HF and urinary symptoms may be directly attributable to worsening HF pathophysiology. A comprehensive literature review was conducted for all publications between January 2000 and November 2017 using the PubMed, Embase, and Cochrane databases. HF represents a major and growing public health problem, with an increased risk of UI and an OAB as comorbidities. Possible effects of HF on urinary problems may be mediated by the prescription of medications for symptomatic relief. Although diuretics are typically used to relieve congestion, and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers improve survival, these classes of drugs have been suggested to worsen urinary symptoms in the presence of HF. Further research is required to understand the impact of UI and an OAB on the HF illness trajectory.

Variation in Cardiovascular Risk Related to Individual Antimuscarinic Drugs Used to Treat Overactive Bladder: A UK Cohort Study

BACKGROUND

Blocking muscarinic receptors could have an effect on cardiac function, especially among elderly patients with overactive bladder (OAB).

STUDY OBJECTIVE

To investigate the risk of cardiovascular (CV) events in users of antimuscarinic drugs to treat OAB.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study of new users of darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium, 18 years or older, in the United Kingdom's Clinical Practice Research Datalink (CPRD), 2004-2012.

OUTCOME MEASUREMENTS AND MAIN RESULTS

Using tolterodine as the reference, we estimated propensity-score-stratified incidence rate ratios (IRRs) for acute myocardial infarction, stroke, CV mortality, major adverse cardiac events (MACE, a combined end point of the previous three), and all-cause death for individual antimuscarinic drugs. The study cohort included 119,912 new users of OAB drugs. The mean age at cohort entry was 62 years, 70% were female, and the mean follow-up was 3.3 years. The adjusted IRR for MACE and current use of oxybutynin compared with current use of tolterodine was 1.14 (95% confidence interval [CI] 1.01-1.30). In contrast, the IRR was 0.65 (CI 0.56-0.76) for current use of solifenacin compared with tolterodine. In this study, performed with health care data, the distribution of risk factors was relatively similar across users of different OAB drugs and, although our analyses controlled for a range of measured potential confounders, residual confounding cannot be ruled out.

CONCLUSIONS

In an observational comparative study of users of medications to treat OAB conducted in routine clinical practice, the risk for CV side effects was increased in users of oxybutynin and decreased in users of solifenacin compared with users of tolterodine.

Cardiovascular Safety of the β3 -Adrenoceptor Agonist Mirabegron and the Antimuscarinic Agent Solifenacin in the SYNERGY Trial

There have been concerns that treatment of overactive bladder with β₃ -adrenoceptor agonists may potentially have detrimental cardiovascular (CV) side effects. We evaluated the CV safety of mirabegron, a β₃ -adrenoceptor agonist, alone and in combination therapy with the antimuscarinic agent solifenacin. The SYNERGY trial was a multinational, multicenter, randomized, double-blind, parallel-group, placebo and active-controlled phase 3 trial. Patients were randomized to receive solifenacin 5 mg + mirabegron 50 mg (combination 5 + 50 mg), solifenacin 5 mg + mirabegron 25 mg (combination 5 + 25 mg), solifenacin 5 mg monotherapy, mirabegron 25 mg monotherapy, mirabegron 50 mg monotherapy, or placebo for a 12-week double-blind treatment period. A total of 3398 patients were included in the study. Mean changes from baseline to the end of therapy in ECG parameters were similar across treatment groups, although there was an increase in heart rate of 1 beat/minute in the mirabegron treatment groups. There were no clinically meaningful differences in change from baseline in QTcF between monotherapies and placebo and between monotherapies and combination therapy. There were very few major CV events: 1 of 853 (0.1%) with a nonfatal myocardial infarction in the combination 5 + 25 mg group, 2 of 848 (0.2%) with a nonfatal stroke in the combination 5 + 50 mg group, and no events in the other groups. This CV safety analysis of the combination of mirabegron and solifenacin showed rates of CV events comparable with those for monotherapy treatments based on assessments of vital signs, electrocardiograms, and adjudicated CV events.

A strategy utilizing ambulatory monitoring and home and clinic blood pressure measurements to optimize the safety evaluation of noncardiovascular drugs with potential for hemodynamic effects: a report from the SYNERGY trial

Supplemental Digital Content is available in the text.

Objective

The aim of this study was to perform a blood pressure (BP) safety evaluation in patients with an overactive bladder receiving solifenacin (an antimuscarinic agent), mirabegron (a β₃-adrenoceptor agonist), or both compared with placebo in the SYNERGY trial.

Patients and methods

Patients were randomized to receive solifenacin 5 mg+mirabegron 50 mg (combination 5+50 mg); solifenacin 5 mg+mirabegron 25 mg (combination 5+25 mg); solifenacin 5 mg; mirabegron 50 mg; mirabegron 25 mg; or placebo for a double-blind 12-week treatment period. Systolic BP, diastolic BP, and heart rate were measured by ambulatory BP monitoring, and in the clinic or home.

Results

A total of 715 patients were analyzed in an ambulatory BP monitoring substudy. At the end of treatment, ambulatory BP monitoring measurements showed no consistent increases from baseline in the mean 24-h systolic BP or diastolic BP for combination versus monotherapy groups or for monotherapy groups versus placebo. Analysis of 1-h BP averages during the 6 h range that included the T_max values of both study drugs showed no significant BP effects. Shift analysis (switch between different normotension/hypertension stages) did not show differences among the active and placebo groups, nor did outlier analysis of major BP changes differ between placebo and active treatment. Similarly, there were no significant signals in the 24-h heart rate. Office and home measurements were consistent with ambulatory BP monitoring findings.

Conclusions

A paradigm of ambulatory BP monitoring analysis designed to test BP safety of noncardiovascular drugs showed that solifenacin plus mirabegron combination therapy during 12 weeks produced no meaningful changes in BP or heart rate.

Cardiovascular effects of antimuscarinic agents and beta3-adrenergic receptor agonist for the treatment of overactive bladder

INTRODUCTION

Overactive bladder (OAB) syndrome is common in the general population, particularly in elderly patients. Antimuscarinic drugs (AMs) are considered the mainstay pharmaceutical treatment of OAB whereas β3-adrenoceptor agonists, such as mirabegron, represent a good alternative. Owing to the important role of muscarinic and β3 receptors in cardiovascular (CV) tissue and to the fact that OAB patients often have CV comorbidities, the safety-profile of these drugs constitute an important challenge.

AREAS COVERED

The aim of this review is to evaluate the CV effects of AMs and mirabegron in OAB. A systematic literature search from inception until December 2017 was performed on PubMed and Medline.

EXPERT OPINION

AMs are generally considered to have good CV safety profile but, however, they may cause undesirable adverse events, such as dry mouth, constipation. CV AEs are rare but noteworthy, the most common CV consequences related to the use of these drugs are constituted by an increase in HR and QT interval. Mirabegron has similar efficacy and tolerability to AMs but causes less adverse events, with either modest hypertension and modest increase in HR (<5 bpm) being the most commonly reported.

Comparison of cardiovascular events among treatments for overactive bladder: a Danish nationwide cohort study

PURPOSE

The purpose of this study is to explore the cardiovascular safety of antimuscarinic drugs to treat overactive bladder (OAB) in Denmark.

METHODS

This was a cohort study using data recorded in Danish registries from patients newly exposed to darifenacin, fesoterodine, oxybutynin, solifenacin, tolterodine, or trospium in 2004-2012. We estimated crude and standardized incidence rates (IRs) for acute myocardial infarction (AMI); stroke; cardiovascular mortality; major adverse cardiac events (MACE, a combined endpoint of the previous three outcomes); and all-cause death for the individual and combined drugs. We also estimated crude, standardized, and propensity score-stratified incidence rate ratios (IRRs) comparing individual antimuscarinic drugs to tolterodine as the reference.

RESULTS

Among 72,917 new users of OAB drugs (mean age, 66 years; 60% women), the standardized IR (95% confidence interval) per 1000 person-years for current use of any OAB drug was 2.7 (2.5-2.9) for AMI, 1.3 (1.2-1.5) for stroke, 7.8 (7.5-8.1) for MACE, 4.8 (4.5-5.0) for cardiovascular mortality, and 15.2 (14.8-15.6) for all-cause mortality. Propensity score-stratified IRRs for current use (reference, tolterodine) were close to the null for all drugs and endpoints.

CONCLUSIONS

We did not identify differences in the risk of cardiovascular events or mortality among users of individual antimuscarinic OAB drugs.

Treating Overactive Bladder in Older Patients with a Combination of Mirabegron and Solifenacin: A Prespecified Analysis from the BESIDE Study

BACKGROUND

The BESIDE study demonstrated that combination therapy (mirabegron and solifenacin 5mg) improved overactive bladder symptoms versus solifenacin 5mg or 10mg, and was well tolerated.

OBJECTIVE

To ensure efficacy and safety is maintained in older patients (>65 yr), who usually experience greater symptom severity and comorbidities, a prespecified subanalysis stratified by age group was conducted.

DESIGN, SETTING, AND PARTICIPANTS

Patients remaining incontinent (≥1 episode during 3-d diary) following 4-wk single-blind daily solifenacin 5mg were randomized 1:1:1 to a daily double-blind combination (solifenacin 5mg and mirabegron 25mg, increased to 50mg at wk 4), solifenacin 5mg or 10mg for 12 wk. Four cohorts stratified by age (<65 yr, ≥65 yr and < 75 yr, ≥75 yr) were investigated.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Efficacy assessments: change from baseline to end of treatment in average daily incontinence (primary) and micturition frequency (key secondary), number of incontinence episodes during the 3-d diary (key secondary), and change from baseline in average daily urgency and urgency incontinence episodes. Safety included treatment-emergent adverse events and vital signs.

RESULTS AND LIMITATIONS

Full analysis set included 2110 patients: 30.9% aged ≥65 yr and 8.9% aged ≥75 yr. At the end of treatment, daily, and 3-d incontinence daily micturitions, urgency, and urgency incontinence, were improved in each treatment group and age group; the largest reductions were observed with combination in each age cohort. There were no notable differences in vital signs or the incidence of treatment-emergent adverse events between treatment and age groups, with the exception of dry mouth, which was highest with solifenacin 10mg.

CONCLUSIONS

Efficacy and safety in the overall population is maintained in older (≥65 yr) and elderly (≥75 yr) patients treated with a combination of solifenacin and mirabegron, or solifenacin monotherapy; irrespective of age, combination was associated with the greatest improvement in overactive bladder symptoms.

PATIENT SUMMARY

This study investigated the effectiveness and safety of a combination of two different treatments (mirabegron 50mg and solifenacin 5mg) or solifenacin (5mg or 10mg) alone in patients aged <65 yr or ≥65 yr, and <75 yr or ≥75 yr with overactive bladder. Symptoms of overactive bladder, such as the urgent need to visit the toilet, incontinence, and frequent urination, were improved with all treatments regardless of the patient's age, but combination treatment demonstrated the greatest benefit, and was well tolerated.

A prospective, double-blind, randomized, two-period crossover, multicenter study to evaluate tolerability and patient preference between mirabegron and tolterodine in patients with overactive bladder (PREFER study)

INTRODUCTION AND HYPOTHESIS

The objective of this study was to assess the tolerability and treatment preference in patients with overactive bladder (OAB) treated with mirabegron or tolterodine.

METHODS

This was a two-period, 8-week crossover, double-blind, phase IV study (PREFER; NCT02138747) in treatment-naive adults with OAB for 3 months or longer randomized to one of four treatment sequences in a 5:5:1:1 ratio (mirabegron/tolterodine, tolterodine/mirabegron, mirabegron/mirabegron, or tolterodine/tolterodine), separated by a washout period of 2 weeks. The primary endpoint was drug tolerability using the Medication Tolerability scale of the OAB Treatment Satisfaction (OAB-S) questionnaire at end of treatment (EoT). Period-by-treatment interactions were analyzed to determine any effect of drug order. Patient preference, change from baseline in OAB symptoms, and treatment-emergent adverse events (TEAEs) were assessed.

RESULTS

A total of 358 randomized patients completed the OAB-S Medication Tolerability scale questionnaire at one or more visits after the baseline evaluation. The mean (95% CI) OAB-S Medication Tolerability scores were significantly higher (better tolerability) for mirabegron (86.29 [83.50, 89.08]) than for tolterodine (83.40 [80.59, 86.20]; p = 0.004). The period-by-treatment interaction was not significant (p = 0.955). Improvements in OAB-S Medication Tolerability scores at EoT were more evident in women, patients aged ≥65 years, and in patients without baseline incontinence, and were greater with mirabegron than with tolterodine extended release. There were no significant differences in patient preference or improvements in OAB symptoms. Significant differences in favor of mirabegron were observed for anticholinergic TEAEs (20.4% vs. 27.4%; p = 0.042) and specifically for gastrointestinal disorders (14.7% vs. 22.5%; p = 0.015).

CONCLUSIONS

Tolerability of mirabegron was significantly higher than that of tolterodine, and patient preference and improvements in OAB symptoms were comparable. Both treatments were well tolerated; however, anticholinergic side effects were higher with tolterodine.

Cardiovascular safety in refractory incontinent patients with overactive bladder receiving add-on mirabegron therapy to solifenacin (BESIDE)

AIMS/OBJECTIVES

In the BESIDE study, combination therapy (antimuscarinic [solifenacin] and β₃ -adrenoceptor agonist [mirabegron]) improved efficacy over solifenacin monotherapy without exacerbating anticholinergic side effects in overactive bladder (OAB) patients; however, a potential synergistic effect on the cardiovascular (CV) system requires investigation.

METHODS

OAB patients remaining incontinent despite daily solifenacin 5 mg during 4-week single-blind run-in, were randomised 1:1:1 to double-blind daily combination (solifenacin 5 mg/mirabegron 25 mg, increasing to 50 mg after week 4), solifenacin 5 or 10 mg for 12 weeks. CV safety assessments included frequency of CV-related treatment-emergent adverse events (TEAEs), change from baseline in vital signs (systolic blood pressure [SBP], diastolic blood pressure [DBP], pulse rate) and electrocardiogram (ECG) parameters.

RESULTS

The frequency of hypertension, tachycardia and ECG QT prolongation, respectively, was low and comparable across combination (1.1%, 0.3%, 0.1%), solifenacin 5 mg (0.7%, 0.1%, 0.1%), and solifenacin 10 mg groups (0.8%, 0%, 0.1%). Adjusted mean (SE) change from baseline to end of treatment (EoT) in SBP, DBP, and pulse rate with combination (0.07 mm Hg [0.38], -0.35 mm Hg [0.26], 0.47 bpm [0.28]), solifenacin 5 mg (-0.93 mm Hg [0.38], -0.45 mm Hg [0.26], 0.43 bpm [0.28]) and solifenacin 10 mg (-1.28 mm Hg [0.38], -0.48 mm Hg [0.26], 0.27 bpm [0.28]) was generally comparable, with the exception of a mean treatment difference of ~1 mm Hg in SBP between combination and solifenacin monotherapy; SBP was unchanged with combination and decreased with solifenacin monotherapy. Mean changes from baseline to EoT in ECG parameters were generally similar across treatment groups, except for QT interval corrected using Fridericia's formula, which was higher with solifenacin 10 mg (3.30 mseconds) vs. combination (0.49 mseconds) and solifenacin 5 mg (0.77 mseconds).

CONCLUSION

The comparable frequency of CV-related TEAEs, changes in vital signs and ECG parameters indicates no synergistic effect on CV safety outcomes when mirabegron and solifenacin are combined.

Oral pharmacotherapy for overactive bladder in older patients: mirabegron as a potential alternative to antimuscarinics

OBJECTIVE

Overactive bladder (OAB) is a particular challenge to treat in older adults with co-morbid conditions taking multiple medications. Antimuscarinics (e.g., solifenacin, fesoterodine) and β3-adrenergic receptor agonists (mirabegron) are similarly efficacious; however, antimuscarinics may be associated with side effects that result in poor persistence and contribute to anticholinergic burden, particularly in those taking other medications with anticholinergic properties. With a mechanism of action distinct from antimuscarinics, mirabegron has a different tolerability profile and does not contribute to anticholinergic burden. The objective of this review was to compare and contrast the tolerability profiles of antimuscarinics and mirabegron in older patients to inform practice.

METHODS

Prospective trials or retrospective subgroup analyses of antimuscarinics for the treatment of OAB in older patients were identified through a search of PubMed. Tolerability data and results of subgroup analyses of mirabegron in patients aged ≥65 and ≥75 years from a pooled analysis of three trials each of 12 weeks and a 1 year trial are described.

RESULTS

Anticholinergic adverse events (AEs) including dry mouth and constipation were more frequent with antimuscarinics versus mirabegron. In patients aged ≥65 years, dry mouth occurred with a six-fold higher incidence with tolterodine extended-release (ER) 4 mg than with mirabegron 25 mg or 50 mg over 12 weeks, and a three-fold higher incidence with tolterodine ER than mirabegron 50 mg over 1 year. Mirabegron had a low incidence of central nervous system effects. A systematic review of the cardiovascular safety profile of mirabegron has not identified any clinically significant effects on blood pressure or pulse rate at therapeutic doses amongst patients aged ≥65 years.

CONCLUSIONS

Mirabegron has a more favorable tolerability profile than antimuscarinics amongst older patients and may provide an improved benefit-to-risk ratio and therefore be considered as an alternative to antimuscarinics for older patients.

Drug therapy of overactive bladder--what is coming next?

After the approval and introduction of mirabegron, tadalafil, and botulinum toxin A for treatment of lower urinary tract symptoms/overactive bladder, focus of interest has been on their place in therapy versus the previous gold standard, antimuscarinics. However, since these agents also have limitations there has been increasing interest in what is coming next - what is in the pipeline? Despite progress in our knowledge of different factors involved in both peripheral and central modulation of lower urinary tract dysfunction, there are few innovations in the pipe-line. Most developments concern modifications of existing principles (antimuscarinics, β₃-receptor agonists, botulinum toxin A). However, there are several new and old targets/drugs of potential interest for further development, such as the purinergic and cannabinoid systems and the different members of the transient receptor potential channel family. However, even if there seems to be good rationale for further development of these principles, further exploration of their involvement in lower urinary tract function/dysfunction is necessary.

Mirabegron in the treatment of overactive bladder

INTRODUCTION

Mirabegron is a selective β3-adrenergic receptor agonist recently developed for the treatment of patients with overactive bladder (OAB), which offers an alternative pharmacological option to the well-established treatment with antimuscarinics (AMs).

AREAS COVERED

This review offers an explanation of the mechanism of action, of the pharmacokinetics and pharmacodynamics of mirabegron and gives readers a complete overview of Phase II and III studies on the clinical efficacy, tolerability and safety of this agent in the setting of OAB treatment.

EXPERT OPINION

Both Phase II and III trials have shown that mirabegron is efficacious and safe in treating patients with OAB. Future research should focus on the assessment of mirabegron concentrations in the CNS and on the evaluation of the potential of the combination of mirabegron with AMs. Another field for future research is represented by the investigation of the interaction of mirabegron with CYP2D6 inhibitors. Furthermore, current literature completely lacks studies on the efficacy and safety of mirabegron in the pediatric population and such trials are awaited.

Rationale for the use of anticholinergic agents in overactive bladder with regard to central nervous system and cardiovascular system side effects

PURPOSE

Central nervous system (CNS) and cardiovascular system (CVS) side effects of anticholinergic agents used to treat overactive bladder (OAB) are underreported. Hence, this review aimed to focus on the mechanisms of CNS and CVS side effects of anticholinergic drugs used in OAB treatment, which may help urologists in planning the rationale for OAB treatment.

MATERIALS AND METHODS

PubMed/MEDLINE was searched for the key words "OAB," "anticholinergics," "muscarinic receptor selectivity," "blood-brain barrier," "CNS," and "CVS side effects." Additional relevant literature was determined by examining the reference lists of articles identified through the search.

RESULTS

CNS and CVS side effects, pharmacodynamic and pharmacokinetic properties, the metabolism of these drugs, and the clinical implications for their use in OAB are presented and discussed in this review.

CONCLUSIONS

Trospium, 5-hydroxymethyl tolterodine, darifenacin, and solifenacin seem to have favorable pharmacodynamic and pharmacokinetic properties with regard to CNS side effects, whereas the pharmacodynamic features of darifenacin, solifenacin, and oxybutynin appear to have an advantage over the other anticholinergic agents (tolterodine, fesoterodine, propiverine, and trospium) with regard to CVS side effects. To determine the real-life situation, head-to-head studies focusing especially on CNS and CVS side effects of OAB anticholinergic agents are urgently needed.