New insights into molecular targets for urinary incontinence

Urinary incontinence (UI) is a disease affecting quality of life of 200 million patients worldwide. It is characterized by involuntary loss of urine. The factors involved are cystitis, detrusor hyperreflexia, spinal injury, benign prostatic hyperplasia, etc. The surge in the number of reviews on this subject indicates the amount of research devoted to this field. The prevalence is increasing at an alarming rate but unfortunately, only a few medications are currently available for this condition. There are peripheral as well as central targets including cholinergic, vanilloid, prostaglandin, kinin, calcium channel, cannabinoid, serotonin, and GABA-receptors, which act by different mechanisms to treat different types of incontinence. Drugs acting on the central nervous system (CNS) increase urinary bladder capacity, volume, or pressure threshold for micturition reflex activation while peripherally acting drugs decrease the amplitude of micturition contraction and residual volume. Anticholinergic drugs specifically M3 receptor antagonists are the first choice but have frequent side effects such as dry mouth, CNS disturbances, etc. Therefore, there is a need to understand the biochemical pathways that control urinary dysfunction to determine the potential to which they can be exploited in the treatment of this condition. This article reviews the central and peripheral molecular targets and the potential therapeutic approaches to the treatment of UI.

Development of oxybutynin chloride topical gel for overactive bladder

Overactive bladder (OAB) is an age-related syndrome often associated with urinary incontinence. Symptoms of OAB, such as urgency, frequency, and nocturia, can be treated effectively with inhibitors of muscarinic acetylcholine receptors. Antimuscarinic agents promote relaxation of the detrusor muscle and may modulate afferent neuronal signals involved in the regulation of the micturition reflex. Despite the availability of an increasing number of oral antimuscarinic agents, treatment persistence among patients with OAB generally appears to be low. This may be attributed, at least in part, to the common occurrence of anticholinergic adverse effects, such as dry mouth, constipation, and dizziness. Oxybutynin is a well-established antimuscarinic agent that is available in a variety of formulations. Transdermal formulations have been developed to avoid the first-pass hepatic and gastrointestinal drug metabolism responsible for the anticholinergic adverse effects often observed with oral delivery of oxybutynin. Oxybutynin chloride topical gel (OTG) is a formulation of oxybutynin that was approved by the US Food and Drug Administration in January 2009. OTG was the result of a systematic evidence-based effort to develop a formulation that preserves the efficacy of oral oxybutynin formulations while eliminating most of their anticholinergic adverse effects. Additional emphasis was put on creating a transdermal formulation with minimal potential for application-site skin reactions. The formulation and pharmacokinetic properties of OTG are reviewed in the context of recently published efficacy and tolerability data from a large multicenter, placebo-controlled Phase III study.

Expanding the Role of Neuromodulation for Overactive Bladder: New Indications and Alternatives to Delivery

From the time that it was granted US Food and Drug Administration approval, neuromodulation has secured a firm position in the treatment algorithm for overactive bladder. With neuromodulation, physicians were able to bridge the gap between the two ends of the treatment spectrum (medical therapy and open surgery). Sacral nerve stimulation has been the most widely used form of neuromodulation. Recent modifications to its design, namely the development of the tined lead and the launching of the refined InterStim II (Medtronic, Minneapolis, MN), have made sacral nerve simulation even less invasive and more effective. While InterStim is maintaining a level of success with these advancements, peripheral means of neuromodulation are being explored. The current literature takes a closer look at posterior tibial and pudendal nerve stimulation as alternatives to sacral nerve stimulation. The field of neuromodulation is also expanding in terms of the target patient population, as it is being used to treat children, patients with neurological disease, and others. As the role of neuromodulation increases, we must continue to assess its efficacy, safety, and cost-effectiveness in comparison to other therapeutic options.

Promise of Urinary Nerve Growth Factor for Assessment of Overactive Bladder Syndrome

Overactive bladder syndrome (OAB) is highly prevalent bladder disorder in men and women. About 10-15% of the population suffers from urgency frequency with or without urgency urinary incontinence. It is estimated that 50-75% of patients with OAB may have urodynamic detrusor overactivity (DO). Urodynamic study invasive and most of the OAB patients might not accept it as a routine assessment. Therefore, a more objective and non-invasive test for diagnosis and assessing DO from OAB patients is needed. Recently, urinary nerve growth factor (NGF) has gained great interest in detecting DO in patients with OAB. Urinary NGF level was found to increase in OAB and urodynamic DO. Urinary NGF levels correlated with severity of OAB symptoms. Patients with either idiopathic or neurogenic DO may have increased urinary NGF levels. Urinary NGF levels have been shown to decrease in patients with patients with OAB and DO who have been well treated with antimuscarinics or botulinum toxin injection, but not in those with persistent OAB after treatment. Not all patients with OAB can have an elevated urinary NGF level; it may also be increased in patients with interstitial cystitis/painful bladder syndrome and other lower urinary tract diseases, suggesting urinary NGF expression could be a product of bladder inflammation and a limited specificity of urinary NGF for diagnosing DO. The source of urinary NGF has not yet been fully explored yet. Nevertheless, urinary NGF level is likely to be a promising biomarker for diagnosis of DO from OAB patients, to monitor therapeutic outcome and predict disease progression.

Effect of baseline symptom severity on continence improvement mediated by oxybutynin chloride topical gel

Background

In a recent placebo-controlled Phase III study, oxybutynin chloride topical gel (OTG) significantly improved urinary continence in patients with overactive bladder. In this post hoc analysis, the effect of incontinence severity on OTG-mediated improvement in continence was evaluated.

Methods

Change from baseline in the number of incontinence episodes was evaluated in patients with two to three incontinence episodes/day (moderate incontinence) and those with more than three incontinence episodes/day (severe incontinence).

Results

In patients with moderate (n = 171) and severe (n = 556) incontinence, reduction in incontinence episodes (mean ± standard deviation) was greater (P < 0.01) with OTG (moderate, −1.7 ± 1.4; severe, −3.6 ± 3.0) than with placebo (moderate, −1.2 ± 1.3; severe, −3.1 ± 3.4). Continence achievement rate with OTG was 48.2% (placebo, 24.4%) among patients with moderate incontinence and 17.8% (placebo, 12.1%) among those with severe incontinence.

Conclusion

Absolute placebo-adjusted reduction in incontinence episodes with OTG was not affected by baseline incontinence severity. Continence achievement was more likely if symptoms were less severe.

Characterization of overactive bladder in women in a primary care setting

BACKGROUND

Overactive bladder (OAB) represents a disorder with overall increasing prevalence in the American population. However, gender-specific characteristics of OAB and how it relates to the general practitioner are not well described. We sought to determine the distribution and characteristics of OAB in women in a primary care setting.

METHODS

Self-administered questionnaires were distributed to patients visiting a family medicine outpatient center. The modified questionnaire included eight questions on evidence of lower urinary tract symptoms (LUTS, OAB-validated 8-question screener [OAB-V8]), two questions on stress urinary incontinence, and one question on incomplete emptying. The questionnaire included demographic characteristics and relevant medical and surgical history. Body mass index was calculated based on weight and height. Chi-square test and risk ratio analysis were used to analyze the relationship between OAB and other independent variables.

RESULTS

Of 1025 questionnaires administered, 386 were completed. Patients ranged from 16 to 97 years, the majority were African American (78.2%), and 49.7% were premenopausal while 50.3% were postmenopausal. OAB was present in 46.4% of premenopausal women and 41.7% of postmenopausal women. OAB was significantly associated with overweight status (body mass index 25.0-29.9, P = 0.042) and obesity (body mass index ≥30, P < 0.001). Overall, obese women were twice as likely to have OAB (relative risk = 1.99, 1.31-3.04) than women with normal weight. OAB was not shown to correlate with race, cigarette use, history of hysterectomy, or parity.

CONCLUSION

OAB was evident in 44% of all female patients surveyed, which is much higher than previously reported estimates. In addition, overweight women were more likely to have OAB. Increased awareness of OAB in the primary care setting should be considered for women's general health.

Update on the management of overactive bladder: patient considerations and adherence

Overactive bladder (OAB) is a common condition that causes a profound impact on an individual’s overall health and quality of life. Muscarinic receptor antagonists are the mainstay of oral pharmacotherapy for OAB. Although all of the medications in this class are significantly more effective than placebo, they are also associated with more adverse events that may limit their overall use. Although newer preparations of these medications have sought to improve tolerability and efficacy through alternative routes of delivery and once-daily dosing, improved adherence to treatment and treatment persistence continue to be an ongoing challenge. An improved understanding of the factors involved in persistence of medical OAB therapy is imperative in efforts to optimize therapeutic benefits in this chronic and potentially morbid condition.

Update on tolterodine extended-release for treatment of overactive bladder

Overactive bladder is a prevalent condition which negatively impacts quality of life and puts a significant economical burden on society. First-line therapy often includes pharmacotherapy with antimuscarinic medications, and numerous research studies have demonstrated that tolterodine extended-release (ER) is an efficacious and tolerable formulation of this class of medication. This review provides an update on the clinical use of tolterodine ER, detailing the current literature on its efficacy, tolerability, adverse effects, and comparability with other commonly prescribed medications for the treatment of overactive bladder.

Prevalence of overactive bladder, its under-diagnosis, and risk factors in a male urologic veterans population

PURPOSE

We assess the prevalence of overactive bladder (OAB) and its risk factors in a male urologic veterans population.

MATERIALS AND METHODS

Validated self-administered questionnaire was prospectively given.

RESULTS

Among 1086 patients, OAB was present in 75%, of which 48% had not been diagnosed/treated. The risk of OAB increased with age. OAB was not associated with BMI, smoking, race, diabetes, CHF, and COPD.

CONCLUSIONS

The prevalence of OAB in this population is under-diagnosed and under-treated.

Fesoterodine for overactive bladder: A review of the literature

BACKGROUND

Overactive bladder (OAB) is a chronic condition affecting both men and women, with prevalence increasing with age. Antimuscarinics form the cornerstone of treatment of OAB. Fesoterodine, a nonselective muscarinic-receptor antagonist, was approved by the US Food and Drug Administration in late 2008 for once daily, oral administration in the treatment of OAB to relieve the symptoms of urinary urge incontinence, urgency, and frequency.

OBJECTIVE

The aim of this review was to provide an overview of the mechanism of action of and clinical trial data for fesoterodine, and to discuss the present status of fesoterodine in the management of OAB.

METHODS

The MEDLINE and Google Scholar databases were searched (June 1, 1999-December 1, 2009) using the terms fesoterodine, overactive bladder, and muscarinic antagonists. Full-text articles in English were selected for reference, and articles presenting the mechanism of action, pharmacokinetics, and data from clinical trials were included. The parameters measured were tolerability, efficacy, and health-related quality of life (HRQoL). Trials involving animals and Phase I studies were excluded.

RESULTS

The initial literature search yielded 48 papers. A total of 20 articles fulfilled the inclusion criteria. In two 12-week, randomized, multicenter, Phase III clinical trials involving patients with increased micturition frequency and urgency and/or urinary urge incontinence (n = 836 and 1132 in each trial), both fesoterodine 4 and 8 mg were associated with significantly improved symptoms of OAB (frequency of micturition, urgency, and urge incontinence) compared with placebo (P < 0.05). In a post hoc analysis of pooled data of the Phase III trials, HRQoL improved significantly with both doses. In a 12-week, Phase Illb trial, fesoterodine 4 and 8 mg led to treatment satisfaction in ∼80% of patients (of 516 enrolled) who were initially unsatisfied with their previous treatment.

CONCLUSION

A review of the literature suggests that fesoterodine is an efficacious and well-tolerated treatment option for patients with OAB.

Randomized Controlled Trial to Treat Benign Prostatic Hyperplasia with Overactive Bladder Using an Alpha-blocker Combined with Anticholinergics

OBJECTIVES

TAABO was a randomized, controlled trial to evaluate the efficacy and safety of combination therapy of tamsulosin (TAM) with propiverine (PROP) in men with both benign prostatic hyperplasia and overactive bladder.

METHODS

It enrolled men 50 years or older who had an international prostate symptom score (IPSS) of 8 or higher, an urgency item score of 1 or higher, and a quality of life (QOL) score of 2 or higher. After 8 weeks of TAM 0.2 mg/day, patients who met the inclusion criteria (8 micturitions per 24 h and 1 urgency per 24 h, evaluated by bladder diary) and were eligible for 12-weeks of continued Treatment II. Five hundred and fifteen patients were enrolled. Thereafter, 214 patients were assigned randomly to receive either TAM alone (n = 67), TAM plus PROP 10 mg (n = 72), or TAM plus PROP 20 mg (n = 75) in Treatment II. The primary efficacy end point was a change in micturitions per 24 h documented in the bladder diary. The change from baseline in urgency episodes per 24 h, IPSS, IPSS/QOL subscore, urinary flow rate and postvoid residual volume were assessed as secondary efficacy measures.

RESULTS

A total of 141 men (47 TAM, 49 TAM plus PROP 10 mg, and 45 TAM plus PROP 20 mg patients) were assessed by week 12. Compared with the TAM, TAM plus PROP 10 mg patients experienced significantly fewer micturitions (P = 0.0261), urgencies (P = 0.0093) per 24 h, lower IPSS storage (P = 0.0465), and IPSS urgency (P = 0.0252) subscores.

CONCLUSIONS

These results suggest that combining TAM and 10 mg of PROP for 12 weeks provides added benefit for men with both benign prostatic hyperplasia and overactive bladder.

Efficacy and Safety of Propiverine and Solifenacin for the Treatment of Female Patients with Overactive Bladder: A Crossover Study

OBJECTIVES

To evaluate the clinical efficacy and tolerability of propiverine and solifenacin in female patients with overactive bladder (OAB).

METHODS

A prospective nonrandomized crossover study of propiverine 20 mg and solifenacin 5 mg was conducted. Female OAB patients were assigned alternately to treatment with propiverine for 8 weeks then solifenacin for 8 weeks (Group P-S) or solifenacin for 8 weeks then propiverine for 8 weeks (Group S-P). At baseline, 8th week and 16th week, symptoms were assessed using overactive bladder symptom score (OABSS).

RESULTS

A total of 121 patients were enrolled. Overall, 38 patients (31.4%) discontinued or dropped out and 83 patients were available for analysis (39 in Group P-S and 44 in Group S-P). In both groups, the total score and each score of OABSS were significantly improved after 8 weeks compared with baseline. In only Group P-S (changing over from propiverine to solifenacin), urgency score in the 16th week was further improved significantly compared with the 8th week. The most bothersome symptom at baseline was urgency incontinence (50.6%), followed by urgency (37.3%). Even after symptom improvement, more than half of the patients were bothered by urgency or urgency incontinence. The incidence of adverse events of moderate and severe grade was higher during propiverine treatment than solifenacin (11.1% vs 2.9%, P = 0.039).

CONCLUSION

Propiverine 20 mg and solifenacin 5 mg were effective for treating female OAB patients. Urgency was further improved after switching from propiverine to solifenacin, but not after switching from solifenacin to propiverine. Solifenacin was better tolerated than propiverine.

The overactive bladder

Urinary urgency and the associated symptoms which comprise overactive bladder are prevalent amongst the general population and adversely affect quality of life. Disease management consists of a sequential series of options starting with behavioural and lifestyle techniques, pharmacological management (antimuscarinics) and, in severe cases, surgical treatment (urinary diversion, neuromodulation, augmentation cystoplasty and detrusor myectomy). There is increasing recognition of pathophysiological mechanisms in the urothelium, interstitial cells and afferent neurons allowing the importance of peripheral integrative interaction to be identified. The hierarchy of the central nervous system control adds additional complexity to understanding the oflower urinary tract function. Some newer methods of treatment include Botulinum toxin A intramural injections, oral beta-3 adrenergic agonists and rho-kinase inhibitors. The lack of a disease generating hypothesis, the lack of animal models for disease and the subjective nature of the central symptom (urgency) still pose considerable theoretical and scientific hurdles that need to be overcome in the treatment of this condition.

Oxybutynin topical gel in the treatment of overactive bladder

Overactive bladder (OAB), often accompanied by urinary incontinence, is most prevalent among the elderly, but also affects many middle-aged men and women in the US. OAB may severely impair quality of life, and its overall economic costs to society are substantial. Although antimuscarinic agents relieve OAB symptoms effectively, treatment persistence generally is low. This has been attributed in part to the occurrence of dry mouth and other anticholinergic adverse events. High plasma concentrations of N-desethyloxybutynin (DEO), an active metabolite of oxybutynin, have been identified as the major cause of anticholinergic adverse effects associated with oral oxybutynin. Transdermal formulations of oxybutynin generate much lower DEO plasma concentrations compared with oral formulations. In a placebo-controlled US Phase III study in patients with OAB, the recently approved oxybutynin topical gel (OTG) was efficacious and well tolerated. Dry mouth occurred in 6.9% of patients treated with OTG and 2.8% of patients on placebo. Incidences of other anticholinergic events were low and similar for OTG and placebo. OTG rarely caused application site skin reactions. OTG provides significant benefits to patients with OAB, particularly those who are sensitive to anticholinergic adverse effects.

Urinary Nerve Growth Factor Levels in Urinary Tract Diseases With or Without Frequency Urgency Symptoms

OBJECTIVES

To measure urinary nerve growth factor (NGF) levels in patients with several urinary tract diseases under different conditions and compare with NGF levels in patients with overactive bladder (OAB) and interstitial cystitis/painful bladder syndrome (IC/PBS).

METHODS

Urinary NGF levels were measured using enzyme-linked immunosorbent assay (ELISA) and normalized by urinary creatinine concentration. Patients with acute bacterial cystitis, urinary tract stone, urothelial cell carcinoma, and OAB patients after antimuscarinic therapy were evaluated. The urinary NGF levels of OAB, IC/PBS and controls from previous studies were used for comparison. NGF levels were compared among subgroups and between urinary tract diseases with or without associated OAB symptoms. The urinary NGF levels were also compared among natural filling, after normal saline filling and after potassium chloride test in a group of OAB and IC/PBS patients.

RESULTS

Patients with acute bacterial cystitis, urinary tract stones or urothelial cell carcinoma had elevated NGF levels that were not associated with the presence of OAB symptoms. Symptomatic cystitis patients who had resolved OAB symptoms after antibiotic treatment had a significant decrease in urinary NGF levels. The urinary NGF levels decreased significantly in OAB patients with effective antimuscarinic treatment for 6 months, but remained stationary and higher than the controls for up to 12 months after treatment.

CONCLUSION

Urinary NGF is not produced solely in patients with OAB or IC/PBS. Acute bacterial cystitis, urinary tract stones and urothelial cell carcinoma can have high urinary NGF production.

The urologist's view of male overactive bladder: discrepancy between reality and belief in practical setting

PURPOSE

In order to gain insight into the physicians' awareness of and attitude towards management of overactive bladder (OAB) in males, we performed a nationwide survey of the current strategies that urologists use to diagnose and manage OAB in male patients.

MATERIALS AND METHODS

A probability sample was taken from the Korean Urological Association Registry of Physicians, and a random sample of 289 Korean urologists were mailed a structured questionnaire that explored how they manage benign prostatic hyperplasia (BPH).

RESULTS

A total of 185 completed questionnaires were returned. The consent rate in the survey was 64.5%. Eighty-one (44%) urologists believed that of all males with lower urinary tract symptoms (LUTS), 20% or more had OAB and 72 (39%) believed that 10-20% had OAB. Half of the urologists surveyed believed that the most bothersome symptom in male OAB patients was nocturia. Seventy-three percent of respondents reported that they prescribed alpha blockers with anticholinergics for first line management, while 19% of urologists prescribed alpha blocker monotherapy but not anticholinergics for OAB patients. Though acute urinary retention (AUR) was considered the anticholinergic adverse event of most concern, the most frequently observed adverse event was dry mouth (95%).

CONCLUSION

The present study provides insights into urologist views of male OAB. There is a discrepancy between the awareness of urologists and actual patterns of diagnosis and treatment of male OAB. This finding indicates the need to develop further practical guidelines based on solid clinical data.

Social, economic, and health utility considerations in the treatment of overactive bladder

Overactive bladder (OAB) is a highly prevalent urinary syndrome with a profound impact on quality of life (QoL) of affected patients and their family because of its adverse effects on social, sexual, interpersonal, and professional function. Cost-of-illness analyses showed the huge economic burden related to OAB for patients, public healthcare systems, and society, secondary to both direct and indirect costs; however, intangible costs related to QoL impact are usually omitted from these analyses. Recently many novel treatment modalities have been introduced and the need to apply the modern methodology of health technology assessment to these treatment strategies was immediately clear in order to evaluate objectively their value in term of both improvement in length/quality of life and costs. Health utilities are instruments that allow a measurement of QoL and its integration in the economic evaluation using the quality-adjusted life-years model and cost-utility analysis. The development of suitable instruments for quantifying utility in the specific group of OAB patients is vitally important to extend the application of cost-utility analysis in OAB and to guide healthcare resources allocation for this disorder. Studies are required to define the cost-effectiveness of available pharmacological and nonpharmacological therapy options for this disorder.

Social, economic, and health utility considerations in the treatment of overactive bladder

Overactive bladder (OAB) is a highly prevalent urinary syndrome with a profound impact on quality of life (QoL) of affected patients and their family because of its adverse effects on social, sexual, interpersonal, and professional function. Cost-of-illness analyses showed the huge economic burden related to OAB for patients, public healthcare systems, and society, secondary to both direct and indirect costs; however, intangible costs related to QoL impact are usually omitted from these analyses. Recently many novel treatment modalities have been introduced and the need to apply the modern methodology of health technology assessment to these treatment strategies was immediately clear in order to evaluate objectively their value in term of both improvement in length/quality of life and costs. Health utilities are instruments that allow a measurement of QoL and its integration in the economic evaluation using the quality-adjusted life-years model and cost-utility analysis. The development of suitable instruments for quantifying utility in the specific group of OAB patients is vitally important to extend the application of cost-utility analysis in OAB and to guide healthcare resources allocation for this disorder. Studies are required to define the cost-effectiveness of available pharmacological and nonpharmacological therapy options for this disorder.

Role of fesoterodine in the treatment of overactive bladder

Muscarinic receptors have long been the target receptors for treatment of patients with overactive bladder (OAB). These patients experience symptoms of urgency, urinary frequency and nocturia, with or without urge incontinence (the involuntary leakage of urine associated with urge). Fesoterodine, a pro-drug, structurally and functionally related to tolterodine, is the newest agent developed for the treatment of OAB. Fesoterodine is broken down to the active metabolite, 5-hydroxy-methyl-tolterodine (5-HMT) by non-specific esterases. This metabolism results in the complete breakdown of the parent compound and is responsible for dose related improvements in clinical efficacy and health related quality of life. Like other antimuscarinic agents including tolterodine, fesoterodine is associated with improvements in clinical variables related both to bladder filling (decreasing micturition frequency and increasing mean voided volume) and urgency (urgency and urge incontinence episodes). Improvements in health related quality of life following treatment with fesoterodine is indicated by improvements in 7 of the 9 variables measured by the King’s Health Questionnaire. Also like other antimuscarinic agents, fesoterodine use is associated with adverse events including dry mouth. However the incidence of dry mouth is reduced with fesoterodine, compared to oxybutynin, due to the improved bladder selectivity of 5-HMT.

Fesoterodine for the treatment of urinary incontinence and overactive bladder

Overactive bladder (OAB) is a highly prevalent condition, affecting males and females. The prevalence increases with age. Behavioral therapy and antimuscarinic therapy remain the first-line therapies for management of OAB. Despite improvements in symptoms, persistence with antimuscarinic therapy has remained low. Multiple factors including patient expectations, adverse effects and cost may affect persistence. Fesoterodine is one of the newest antimuscarinic agent approved for the management of OAB. It is unique in that it shares the same active metabolite as tolterodine, 5-hydoxymethyltolterodine (5-HMT); however, this conversion is established via ubiquitous esterases and not via the cytochrome P450 system, thus providing a faster and more efficient conversion to 5-HMT. Fesoterodine is available in 2 doses, 4 mg and 8 mg. Clinical trials have established a dose response relationship in efficacy parameters as well as improvements in quality of life. As with all antimuscarinics, dry mouth and constipation are the more common side effects. A combination of medical therapy and behavioral therapy improves the overall outcome in management of OAB. Dose flexibility may help improve efficacy outcomes and patient education on the management of common adverse effects may improve tolerability with these agents.

Oxybutynin extended release for the management of overactive bladder: a clinical review

Overactive bladder (OAB) is a common condition which negatively impacts the quality of life of afflicted patients. This can result in alterations in social interactions at home, in the workplace and in the community, often leading to depression and poor self esteem as well as loss of productivity. Traditional mainstays of treatment include both behavioral therapy and pharmacotherapy. Oxybutynin immediate release (IR) represents the first such medication approved by the FDA specifically for treatment of OAB in 1975. Nevertheless, bothersome side effects in addition to thrice daily dosing often led to treatment cessation which raised the question that patients may actually prefer to live with their OAB symptoms rather than incur side effects or complex dosing schemes. Pharmacological advances ultimately led to development of a long-acting formulation of oxybutynin in the form of oxybutynin extended release (ER) with the hope that this drug would maintain efficacy while decreasing bothersome side effects and improve compliance with the convenience of once daily dosing regimen. This paper will review the major clinical studies involving oxybutynin ER as well as its role in different patient populations and potential concerns with its use.

The safety and efficacy of tolterodine extended release in the treatment of overactive bladder in the elderly

After lifestyle and behavioral measures to control overactive bladder, the mainstay of pharmacological treatment is the use of antimuscarinic therapy. Overactive bladder predominantly affects older people, who experience the most severe disease, and are also at a greater risk of side effects from antimuscarinic therapy. Thus it is imperative that data are available on the efficacy and tolerability of this group of drugs when used in older people. This article reviews the pathophysiology of the condition, its effect on the elderly and the evidence for the use of extended release tolterodine in the elderly using data from placebo and active drug controlled studies.

Update on duloxetine for the management of stress urinary incontinence

Duloxetine is a relatively balanced serotonin and noradrenaline reuptake inhibitor (SNRI), which is the first drug with widely proven efficacy to have been licensed for the medical treatment of women with stress urinary incontinence (SUI). Despite favorable results from randomized controlled trials, surgical management continues to be the mainstay of treatment for SUI. In this review we explore the pharmacology of duloxetine in the nervous system and lower urinary tract, and the evidence for its use in the management of women with urinary incontinence.

Afferent nerve regulation of bladder function in health and disease

The afferent innervation of the urinary bladder consists primarily of small myelinated (Adelta) and unmyelinated (C-fiber) axons that respond to chemical and mechanical stimuli. Immunochemical studies indicate that bladder afferent neurons synthesize several putative neurotransmitters, including neuropeptides, glutamic acid, aspartic acid, and nitric oxide. The afferent neurons also express various types of receptors and ion channels, including transient receptor potential channels, purinergic, muscarinic, endothelin, neurotrophic factor, and estrogen receptors. Patch-clamp recordings in dissociated bladder afferent neurons and recordings of bladder afferent nerve activity have revealed that activation of many of these receptors enhances neuronal excitability. Afferent nerves can respond to chemicals present in urine as well as chemicals released in the bladder wall from nerves, smooth muscle, inflammatory cells, and epithelial cells lining the bladder lumen. Pathological conditions alter the chemical and electrical properties of bladder afferent pathways, leading to urinary urgency, increased voiding frequency, nocturia, urinary incontinence, and pain. Neurotrophic factors have been implicated in the pathophysiological mechanisms underlying the sensitization of bladder afferent nerves. Neurotoxins such as capsaicin, resiniferatoxin, and botulinum neurotoxin that target sensory nerves are useful in treating disorders of the lower urinary tract.

The elusive electromyogram in the overactive bladder: a spark of understanding

It has been said that a technique capable of recording a urinary bladder electromyogram could be useful in the clinical evaluation of the detrusor neuropathies and myopathies implicated in the generation of lower urinary tract symptoms. However, in contrast to electromyography of skeletal and cardiac muscle, detrusor smooth muscle electromyography has remained in its infancy despite 50 years of scientific effort. The principal problems appear to be isolation of the real signal from artefacts, and the doubtful existence of electromyographic activity during cholinergic muscle contraction. The discovery of purinergic neuromuscular transmission in the overactive human bladder has renewed interest in detrusor electromyography as, in contrast to cholinergic mechanisms, purinergic mechanisms can generate extracellular electrical activity. In this paper, the development and validation of a novel technique for recording electrical activity from neurologically intact guinea-pig and human detrusor in vitro is described. A purinergic electromyographic signal is characterised and it is shown that detrusor taken from overactive human bladders has a greater propensity to generate electromyographic activity than normal by virtue of an aberrant purinergic mechanism.

Pharmacologic management of overactive bladder

Overactive bladder (OAB) is a prevalent and costly condition that can affect any age group. Typical symptoms include urinary urgency, frequency, incontinence and nocturia. OAB occurs as a result of abnormal contractions of the bladder detrusor muscle caused by the stimulation of certain muscarinic receptors. Therefore, antimuscarinic agents have long been considered the mainstay of pharmacologic treatment for OAB. Currently, there are five such agents approved for the management of OAB in the United States: oxybutynin, tolterodine, trospium, solifenacin and darifenacin. This article summarizes the efficacy, contraindications, precautions, dosing and common side effects of these agents. All available clinical trials on trospium, solifenacin and darifenacin were reviewed to determine its place in therapy.

Cerebral control of the bladder in normal and urge-incontinent women

AIM

To identify age-related changes in the normal brain/bladder control system, and differences between urge incontinence in younger and older women, as shown by brain responses to bladder filling; and to use age, bladder volume, urge incontinence and detrusor overactivity (DO) as probes to reveal control system function. Functional MRI was used to examine regional brain responses to bladder infusion in 21 females (26-85 years): 11 "cases" with urge incontinence and DO (proven previously) and 10 normal "controls". Responses and their age dependence were determined at small and large bladder volumes, in whole brain and in regions of interest representing right insula and anterior cingulate (ACG). In "controls", increasing bladder volume/sensation led to increasing insular responses; with increasing age, insular responses became weaker. In younger "cases", ACG responded abnormally strongly at large bladder volumes/strong sensation. Elderly "cases" showed strong ACG responses even at small bladder volume but more moderate responses at larger volumes; if DO occurred, pontine micturition center (PMC) activation did not increase.

CONCLUSION

Among normal "controls", increasing age leads to decreased responses in brain regions involved in bladder control, including right insula, consistent with its role in mapping normal bladder sensations. Strong ACG activation occurs in urge-incontinent "cases" and may be a sign of urgency, indicating recruitment of alternative pathways when loss of bladder control is feared. Easier ACG provocation in older "cases" reflects lack of physiological reserve or different etiology. ACG responses seem associated with PMC inhibition: reduced ACG activity accompanies failure of inhibition (DO).

What is the prevalence of overactive bladder symptoms in a lower socioeconomic female population?: A suggestion for a study in India

Although it is suggested that in the United States overactive bladder affects one out of six individuals, this estimation may represent a subset of the population. Using a Pubmed literature search, many studies do not address those in a lower socioeconomic strata and the prevalence of overactive bladder may be higher. Overactive bladder symptoms may be under-reported in this population due to social stigma, lack of education or inaccessibility to medical care. This paper proposes to perform an epidemiological study incorporating validated incontinence questionnaires to assess the prevalence of overactive bladder symptoms among Indian women.

Diagnosis of interstitial cystitis/ painful bladder syndrome in patients with overactive bladder symptoms

Overactive bladder (OAB) and interstitial cystitis (IC) have similar symptoms, including urinary urgency/frequency and nocturia, making them difficult to differentiate on the basis of clinical presentation alone. Both conditions may represent a clinical manifestation of a hypersensitive bladder and should be included in the differential diagnosis for patients who present with urgency/ frequency. It is especially important that IC be considered in patients with OAB that is refractory to treatment. The proposed diagnostic framework may be useful for differentiating IC from OAB and for facilitating appropriate treatment.

Effects of bladder training and/or tolterodine in female patients with overactive bladder syndrome: a prospective, randomized study

We compared the effects of bladder training and/or tolterodine as first line treatment in female patients with overactive bladder (OAB). One hundred and thirty-nine female patients with OAB were randomized to treatment with bladder training (BT), tolterodine (To, 2 mg twice daily) or both (Co) for 12 weeks. Treatment efficacy was measured by micturition diary, urgency scores and patients' subjective assessment of their bladder condition. Mean frequency and nocturia significantly decreased in all treatment groups, declining 25.9% and 56.1%, respectively, in the BT group; 30.2% and 65.4%, respectively, in the To group; and 33.5% and 66.3%, respectively in the Co group (p<0.05 for each). The decrease in frequency was significantly greater in the Co group than in the BT group (p<0.05). Mean urgency score decreased by 44.8%, 62.2% and 60.2% in the BT, To, and Co groups, respectively, and the improvement was significantly greater in the To and Co groups than in the BT group (p<0.05 for each). Although BT, To and their combination were all effective in controlling OAB symptoms, combination therapy was more effective than either method alone. Tolterodine alone may be instituted as a first-line therapy, but may be more effective when combined with bladder training.

Solifenacin significantly improves all symptoms of overactive bladder syndrome

Overactive bladder syndrome (OAB) is a chronic condition characterised by urgency, with or without associated urge incontinence. Solifenacin succinate is a once daily, bladder selective antimuscarinic available in two doses (5 and 10 mg). The recommended dose is 5 mg once daily and can be increased to 10 mg once daily if 5 mg is well tolerated. This article presents pooled efficacy and safety data from four large, placebo-controlled, multinational phase III trials of solifenacin succinate with a total enrolment of over 2800 patients. Data from these trials show that solifenacin 5 and 10 mg once daily is significantly more effective than placebo at reducing urgency, incontinence, micturition frequency and nocturia and at increasing volume voided per micturition. Adverse events were mainly mild-to-moderate in all treatment groups. The results of these phase III trials support the use of solifenacin in the treatment of OAB.

Oxybutynin: an overview of the available formulations

Overactive bladder (OAB) is a common problem presented to by physicians. Standard treatment with antimuscarinic medication is directed at suppressing involuntary detrusor contractions by blocking the binding of acetylcholine to muscarinic receptors in the bladder. Oxybutynin chloride is the first of several antimuscarinic medications to be marketed for OAB. Although efficacious for treating OAB symptoms, the side effects and suboptimal dosing regimen decrease its utility. To improve patient compliance and tolerability, alternative delivery systems for oxybutynin have subsequently been developed and include a once-daily formulation and a transdermal system. The currently available formulations of oxybutynin are the subject of this review.

Botulinum toxin for the treatment of idiopathic and neurogenic overactive bladder: state of the art

The pharmacologic treatment of overactive bladder and detrusor overactivity, whether idiopathic or neurogenic, has centered around blocking muscarinic receptors on the detrusor muscle. Although newer agents have been developed with better tolerability and safety, the basic mechanism by which the "irritable" detrusor is treated has not changed in decades. Although effective in many cases of idiopathic and neurogenic detrusor overactivity and overactive bladder, antimuscarinic agents fall short in many other cases because of lack of efficacy and/or tolerability. For the past several years, there has been increasing evidence to support the use of botulinum toxin for the treatment of detrusor overactivity and overactive bladder syndrome not effectively treated by anticholinergics. From early open-label studies to the more recent randomized, controlled trials, efficacy and tolerability data have been very encouraging. Botulinum toxin is not yet approved by the US Food and Drug Administration for the treatment of detrusor overactivity and overactive bladder, but the positive results seen thus far cannot be ignored.

Management of overactive bladder with transdermal oxybutynin

In clinical trials, transdermal oxybutynin (OXY-TDS) has shown comparable efficacy and improved tolerability when compared with conventional pharmacotherapy. Systemic anticholinergic adverse effects are comparable to those with placebo, most likely owing to avoidance of first-pass hepatic metabolism and conversion of oxybutynin to N-desethyloxybutynin. OXY-TDS has predictable pharmacokinetic absorption and elimination parameters, as shown in both in vitro and in vivo studies. Consistent plasma concentrations of oxybutynin avoid labile peak and trough concentrations seen with immediate-release formulations, paralleling extended-release drug delivery. This novel drug delivery system has unique dermatologic skin application site reactions, including erythema and pruritus. Skin reactions are usually mild and can be minimized by varying the site of patch application. Most eczematous dermatologic reactions can be appropriately treated with a moderately potent topical corticosteroid cream. A small percentage of patients will discontinue therapy as a result of bothersome application site skin reactions.

Medical therapy for benign prostatic hyperplasia: new terminology, new concepts, better choices

This article discusses 3 areas of medical therapy for benign prostatic hyperplasia (BPH) that are undergoing extensive research and evaluation: 1) the use of muscarinic receptor antagonists to treat lower urinary tract symptoms (LUTS) in men with BPH; 2) the definition of an "enlarged prostate"; and 3) sexual function and LUTS. Fears of worsening obstructive symptoms or causing acute urinary retention often keep practitioners from prescribing muscarinic receptor antagonists to men who might have concomitant bladder outlet obstruction; a multicenter, multinational, double-blind study showed that tolterodine is safe for men with low postvoid residual volumes. Most urologists accept that a prostate volume of more than 40 mL is consistent with an enlarged prostate; there is more debate regarding prostate volumes of 30 to 40 mL. Recently presented data suggest that combination medical therapy might be effective for men having prostates with volumes of more than 25 mL. The association between voiding and sexual function has been increasingly recognized and investigated, and there seem to be common pathophysiologic mechanisms governing both conditions. Targeted treatment algorithms addressing both conditions seem warranted.

In vitro and in vivo characterization of a novel naphthylamide ATP-sensitive K+ channel opener, A-151892

1. Openers of ATP-sensitive K(+) channels are of interest in several therapeutic indications including overactive bladder and other lower urinary tract disorders. This study reports on the in vitro and in vivo characterization of a structurally novel naphthylamide N-[2-(2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl-ethyl)-naphthalen-1-yl]-acetamide (A-151892), as an opener of the ATP-sensitive potassium channels. 2. A-151892 was found to be a potent and efficacious potassium channel opener (KCO) as assessed by glibenclamide-sensitive whole-cell current and fluorescence-based membrane potential responses (-log EC(50)=7.63) in guinea-pig bladder smooth muscle cells. 3. Evidence for direct interaction with KCO binding sites was derived from displacement of binding of the 1,4-dihydropyridine opener [(125)I]A-312110. A-151892 displaced [(125)I]A-312110 binding to bladder membranes with a -log Ki value of 7.45, but lacked affinity against over 70 neurotransmitter receptor and ion channel binding sites. 4. In pig bladder strips, A-151892 suppressed phasic, carbachol-evoked and electrical field stimulus-evoked contractility in a glibenclamide-reversible manner with -log IC(50) values of 8.07, 7.33 and 7.02 respectively, comparable to that of the potencies of the prototypical cyanoguanidine KCO, P1075. The potencies to suppress contractions in thoracic aorta (-log IC(50)=7.81) and portal vein (-log IC(50)=7.98) were not substantially different from those observed for suppression of phasic contractility of the bladder smooth muscle. 5. In vivo, A-151892 was found to potently suppress unstable bladder contractions in obstructed models of unstable contractions in both pigs and rats with pED(35%) values of 8.05 and 7.43, respectively. 6. These results demonstrate that naphthylamide analogs exemplified by A-151892 are novel K(ATP) channel openers and may serve as chemotypes to exploit additional analogs with potential for the treatment of overactive bladder and lower urinary tract symptoms.

Overview of overactive bladder, prostatitis, and lower urinary tract symptoms for the primary care physician

As an increasing number of treatment options for urologic disorders become available, patients with these conditions are more often able to be managed in the primary care setting. Primary care physicians, therefore, must become more knowledgeable of the proper urologic terminology and the screening tools that have traditionally been used by urologists. To that end, this article reviews the terminology associated with lower urinary tract symptoms and describes the evaluation and treatment of patients presenting with these symptoms. The diagnoses of overactive bladder and prostatitis are discussed, as well as the therapeutic options available for these patients.

Transdermal therapy for overactive bladder: present and future

Transdermal delivery of certain pharmacologic agents offers distinct advantages, including the ability to bypass the gastrointestinal environment, fewer side effects, and increased bioavailability. For many patients with overactive bladder (OAB), transdermal therapy is more convenient than oral therapy, and the altered drug metabolism offers the advantages of an improved side-effect profile and enhanced steady-state plasma concentrations. The "newness" of transdermal delivery to physicians treating OAB is a potential limitation; however, much insight can be gained from the successful use of transdermal systems for delivery of other therapies, such as agents for chronic pain, hormone replacement therapy, and contraceptives. The transdermal oxybutynin system for OAB reduces the level of oxybutynin metabolites, resulting in a low incidence of anticholinergic side effects, and provides efficacy similar to that of standard doses of currently available oral preparations. However, there is room for improvement of the transdermal system, especially with respect to providing increased efficacy over currently available oral medications and reducing and treating local skin reactions at the application site.

Treatment of the overactive bladder: where we stand in 2003

The understanding and management of overactive bladder (OAB) continue to evolve. However, argument persists as to the exact incidence of the disease and the underlying pathophysiology of the symptom complex. Individual differences in symptomatic impact and, more importantly, personal coping partially account for the disparity noted among demographic estimates currently extant. Likewise, the underlying pathophysiology that leads to overt OAB syndrome is, as yet, incompletely characterized. Muscarinic receptor behavior provides partial explanation, but other complex underlying receptor and neurotransmitter interactions probably are also a component of the presentation. Current state-of-the-art therapy relies on an exclusionary diagnosis prior to the inception of therapy. Ideally, optimal therapy involves behavioral and pharmacologic interventions combined to maximize therapeutic results. Antimuscarinic therapy provides only a degree of relief from the bothersome symptoms of OAB. As yet, few options exist for patients who have previously failed oral antimuscarinic intervention. Herein, the evolving OAB landscape will be considered as it currently stands in 2003. The current lack of optimal symptom control will most assuredly lead to the development of new pathways for OAB treatment.

Transdermal systems for overactive bladder: principles and practice

The transdermal system for delivery of medication to treat overactive bladder may provide an improved efficacy-to-tolerability ratio by regulating serum drug levels; avoiding gastrointestinal and hepatic metabolism, which is important when the metabolite has a lesser therapeutic index than the parent drug; and achieving clinical efficacy with a lower total drug burden. Additional advantages may include increased compliance and obviation of the need for oral drug administration, which is especially beneficial for the patient who is taking multiple oral medications or is caregiver-dependent. An efficient patch system must preserve the physical integrity of the drug layer, provide adequate adhesion, store and release the drug and permeation-enhancing agent in a predictable manner, promote consistent absorption through the skin regardless of location or skin or subcutaneous tissue differences, demonstrate dose proportionality, maintain skin integrity during product use and removal, and be cosmetically acceptable. A novel transdermal delivery system that incorporates an occlusive layer covering an acrylic adhesive containing the active agent oxybutynin and a skin permeation enhancer has been demonstrated in clinical trials to achieve these goals.

Overactive bladder in special patient populations

It is now well accepted that overactive bladder (OAB) negatively affects the quality of life of a large number of persons and that the primary mode of therapy is the use of medication-currently antimuscarinic agents. However, it is also important for physicians to understand how the use of these drugs affects specific groups of patients. Most of the concern in this area focuses on the potential for these populations to experience certain adverse events or side effects from the use of antimuscarinic agents; this has prevented these drugs from being prescribed in these populations to the same degree as in the general population of OAB sufferers. The purpose of this article is to review these specific populations of OAB patients, including pediatric, geriatric, and pregnant patients, men with prostate problems, and patients in whom OAB is of neurogenic origin, and to discuss what is currently known about the use of antimuscarinic agents in these groups.

Neurophysiology of lower urinary tract function and dysfunction

With the continued aging of the population, the incidence of conditions associated with bladder control will continue to grow. In this article, we review the neurophysiology and pathophysiology of the bladder and urethra and discuss logical concepts for the development of novel drug therapy that can better help the expanding population of patients with bladder control problems.

Spontaneous phasic activity of the pig urinary bladder smooth muscle: characteristics and sensitivity to potassium channel modulators

A hallmark for unstable bladder contractions is hyperexcitability and changes in the nature of spontaneous phasic activity of the bladder smooth muscle. In this study, we have characterized the spontaneous activity of the urinary bladder smooth muscle from the pig, a widely used model for studying human bladder function. Our studies demonstrate that phasic activity of the pig detrusor is myogenic and is influenced by the presence of urothelium. Denuded strips exhibit robust spontaneous activity measured as mean area under the contraction curve (AUC=188.9+/-15.63 mNs) compared to intact strips (AUC=7.3+/-1.94 mNs). Spontaneous phasic activity, particularly the amplitude, is dependent on both calcium entry through voltage-dependent calcium channels and release from ryanodine receptors as shown by inhibition of spontaneous activity by nifedipine and ryanodine respectively. Inhibition of BK(Ca) channels by iberiotoxin (100 nM) resulted in an increase in contraction amplitude (89.1+/-20.4%) and frequency (92.5+/-31.0%). The SK(Ca) channel blocker apamin (100 nM) also increased contraction amplitude (69.1+/-24.3%) and frequency (53.5+/-13.6%) demonstrating that these mechanisms are critical to the regulation of phasic spontaneous activity. Inhibition of K(ATP) channels by glyburide (10 microM) did not significantly alter myogenic contractions (AUC=18.5+/-12.3%). However, K(ATP) channel openers (KCOs) showed an exquisite sensitivity for suppression of spontaneous myogenic activity. KCOs were generally 15 fold more potent in suppressing spontaneous activity compared to contractions evoked by electrical field-stimulation. These studies suggest that potassium channel modulation, particularly K(ATP) channels, may offer a unique mechanism for controlling spontaneous myogenic activity especially those associated with the hyperexcitability occurring in unstable bladders.

The future of bladder control-intravesical drug delivery, a pinch of pepper, and gene therapy

The incidence of urinary incontinence and overactive bladder problems will continue to grow as the population ages. Future treatments are likely to include an implantable drug delivery system, gene therapy, and the intravesical use of the vallinoids capsaicin and resiniferatoxin (RTX). An understanding of the urothelium is essential for effective design of these therapies. Intravesical anticholinergic drug treatment is currently not widely used, but intravesical pumps are under development to provide less cumbersome treatment methods and will provide nonsurgical options for patients who cannot tolerate oral anticholinergic agents. Research on the use of capsaicin as an intravesicular drug has had limited success, but trials have confirmed the efficacy of intravesical capsaicin for detrusor hyperreflexia. RTX is as effective as capsaicin but without side effects, such as pain and inflammatory neuropeptide release. RTX treatment may eliminate the need for surgical and other drug treatments of lower urinary tract dysfunction in patients with spinal cord injuries. Gene therapy will change the practice of urology by addressing the deficiencies that cause symptoms rather than attacking the symptoms themselves.