Pharmacological agents for the treatment of urinary incontinence due to overactive bladder

Treatment strategies for clozapine-induced nocturnal enuresis and urinary incontinence: a systematic review

BACKGROUND

Clozapine is the most effective medication for treatment-refractory schizophrenia but is associated with significant adverse drug reactions, including nocturnal enuresis and urinary incontinence. This side effect can be burdensome and lead to medication nonadherence and psychotic relapse. Evidence to guide treatment of clozapine-induced nocturnal enuresis and urinary incontinence is sparse. We therefore aimed to synthesize the evidence base to guide management for clinicians, patients, and their carers.

METHODS

We systematically searched PubMed, Embase, PsycInfo, CINAHL, and the Cochrane Trial Registry databases from inception to May 2021 for publications on management of clozapine-induced nocturnal enuresis and urinary incontinence using a PROSPERO preregistered search strategy.

RESULTS

We identified 22 case reports and case series describing 74 patients. Interventions included clozapine dose reduction, nonpharmacological treatment, and pharmacological treatments. Among pharmacological treatments, desmopressin, oxybutynin, trihexyphenidyl, tolterodine, imipramine, amitriptyline, ephedrine, pseudoephedrine, aripiprazole, and verapamil were associated with complete resolution of nocturnal enuresis and urinary incontinence. Balancing evidence for effectiveness against risk of adverse effects, we developed a management framework for clozapine-induced nocturnal enuresis and urinary incontinence.

CONCLUSIONS

Following assessment of urological, psychiatric, pharmacological, and common comorbid medical issues, first-line treatments should be nonpharmacological, including bathroom alarms, voiding before bedtime, and nocturnal fluid restriction. If these interventions do not provide adequate relief, aripiprazole should be trialed. Desmopressin may be considered for severe refractory cases, but monitoring for hyponatremia is essential.

Potential of Mirabegron and its Extended-release Formulations for the Treatment of Overactive Bladder Syndrome

BACKGROUND

Overactive bladder syndrome is a broadly occurring urological disorder with a distressing impact on the quality of life. The commonly used antimuscarinic drugs show poor patient compliance because of unsatisfactory potency, tolerability and high occurrence of adverse effects such as dry mouth, blurred vision, constipation, dizziness etc. Mirabegron is the first approved β3-adrenoreceptor agonist, used as mono or in combination therapies for overactive bladder syndrome.

OBJECTIVE

The present review provides an insight into the mechanism, pharmacokinetics, toxicokinetics, clinical trials and the development of various conventional and modified-release dosage forms of mirabegron for the treatment of overactive bladder syndrome.

RESULTS

The clinical trials of phase II and phase III of mirabegron demonstrated symptomatic relief from the overactive bladder without disturbing the micturition cycle. To date, mirabegron showed promising results for safety, tolerability and efficacy in patients with overactive bladder syndrome. The modified-release tablet dosage form of mirabegron appear to be a proficient and suitable replacement for antimuscarinics and revealed the tremendous potential to overcome the adverse effects of conventional antimuscarinic drugs like Oxybutyline chloride ER, Detrol LA, VESIcare, etc. Conclusion: Mirabegron shows a distinct mode of action, i.e., targeting β3-adrenoreceptors and improving bladder storage without altering void contractions. The limited side effects, high safety, efficacy and tolerability of mirabegron present an adequate substitute to antimuscarinics. However, long-term analysis and clinical studies are prerequisites for assessing the safety, tolerability and efficacy profile of mirabegron.

Big-conductance Ca2+-activated K+ channels in physiological and pathophysiological urinary bladder smooth muscle cells

Contraction and relaxation of urinary bladder smooth muscle cells (UBSMCs) represent the important physiological functions of the bladder. Contractile responses in UBSMCs are regulated by a number of ion channels including big-conductance Ca²⁺- activated K⁺ (BK) channels. Great progress has been made in studies of BK channels in UBSMCs. The intent of this review is to summarize recent exciting findings with respect to the functional interactions of BK channels with muscarinic receptors, ryanodine receptors (RyRs) and inositol triphosphate receptors (IP₃Rs) as well as their functional importance under normal and pathophysiological conditions. BK channels are highly expressed in UBSMCs. Activation of muscarinic M₃ receptors inhibits the BK channel activity, facilitates opening of voltage-dependent Ca²⁺ (Ca_V) channels, and thereby enhances excitability and contractility of UBSMCs. Signaling molecules and regulatory mechanisms involving RyRs and IP₃Rs have a significant effect on functions of BK channels and thereby regulate cellular responses in UBSMCs under normal and pathophysiological conditions including overactive bladders. Moreover, BK channels may represent a novel target for the treatment of bladder dysfunctions.

Urinary Incontinence during Sleep Associated with Extended Release Form of Bupropion HCI

Bupropion hydrochloride (HCI) is an antidepressant that acts as a norepinephrine and dopamine reuptake inhibitor and has three different dosage forms including immediate release (IR), sustained release (SR), and extended release (ER). Despite its relatively safe side effect profile bupropion may cause several side effects. Here, we aimed to report a case with major depression using extended release form of bupropion hydrochloride who was presented with urinary incontinence during sleep, an uncommon side effect of bupropion.

Experience with imidafenacin in the management of overactive bladder disorder

Overactive bladder (OAB) is a chronic syndrome defined by symptoms of urinary urgency with no underlying medical causes. First-line treatment of OAB comprises fluid intake advice and bladder training, supplemented by anticholinergic drugs if necessary. Owing to the chronic nature of OAB, the ideal anticholinergic treatment should have good long-term efficacy and tolerability. There are many anticholinergics available, although some of these are not specific for the bladder and can cause adverse effects such as dry mouth, constipation, blurred vision or cognitive impairment. Imidafenacin (a newer anticholinergic which has been marketed in Japan since 2007) was developed to improve the tolerability of anticholinergic therapy. This article summarizes the pharmacological properties, pharmacokinetics, clinical efficacy and tolerability of imidafenacin in the treatment of OAB. Data from key clinical studies of imidafenacin show that it has a fast onset of action and is effective for the treatment of OAB. It selectively binds to muscarinic receptors in the bladder and is associated with a good safety profile compared with other anticholinergics. The clinical efficacy, superior tolerability and adjustable dosing of imidafenacin make it a good anticholinergic for the treatment of OAB.

Development and Validation of a Specific Stability Indicating High Performance Liquid Chromatographic Methods for Related Compounds and Assay of Solifenacin Succinate

Gradient, reverse phase liquid chromatographic methods were developed separately for the related compounds and solifenacin succinate, an active pharmaceutical ingredient used for the treatment of overactive bladder. Gradient LC method was employed for related compounds. The mobile phase-A contains a 0.01 M phosphate buffer pH:3.5±0.05with orthophosphoric acid (88%) and mobile phase-B contains a mixture of acetonitrile and water in the ratio of 90 : 10(v/v). The flow rate was 1.0 mL/minute, column temperature was kept at 35°C, and detection was monitored at 220 nm. In the developed HPLC method the resolution between solifenacin succinate and its closely eluting impurity, that is, solifenacin N-oxide was found to be greater than 3.0. The drug was subjected to stress conditions such as hydrolysis, oxidation, photolysis, and thermal degradation. Considerable degradation was found to occur in only oxidative stress condition. Degradation product formed during oxidative stress condition was found to be impurity-C and it can be identified by LC-MS. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed RP-LC method was validated as per ICH guidelines. We also developed LC-MS/MS method for determination and identification of these impurities in solifenacin succinate.

Alteration in TRPV1 and Muscarinic (M3) receptor expression and function in idiopathic overactive bladder urothelial cells

AIM

To examine function of both cholinergic (muscarinic) and TRPV1 receptors in human bladder urothelial (HBUC) from non-neurogenic overactive bladder (OAB) patients as compared to control subjects.

METHODS

Primary HBUC cultures were derived from cystoscopic biopsies from OAB and control subjects. Muscarinic and TRPV1 function was assessed by acetylcholine (5 μm) or capsaicin (0.5 μm) evoked ATP release, measured by luciferase assay. Overall, expression of TRPV1 and muscarinic M3 receptors in bladder urothelial cells was accomplished using western immunoblotting.

RESULTS

Our findings revealed that the response to acetylcholine in OAB HBUC cultures (which was blocked by the nonselective muscarinic antagonist, atropine methyl nitrate or AMN) was not significantly different than from controls. The acetylcholine M3 receptor was slightly decreased as compared to control. In contrast, OAB HBUC cultures exhibited a capsaicin hypersensitivity and augmented release of ATP (3.2 fold higher), which was blocked by the antagonist capsazepine. The increase in capsaicin sensitivity correlated with increased urothelial TRPV1 expression.

CONCLUSION

Though characterized in a small number of subjects, augmented release of urothelial-derived transmitters such as ATP could 'amplify' signalling between and within urothelial cells and nearby afferent nerves.

Phase IIb, multicenter, double-blind, randomized, placebo-controlled, parallel-group study to determine effects of elocalcitol in women with overactive bladder and idiopathic detrusor overactivity

OBJECTIVE

To evaluate the efficacy and safety of elocalcitol in the treatment of women with overactive bladder and idiopathic detrusor overactivity.

METHODS

The study was a multicenter, double-blind, randomized, placebo-controlled, parallel-group trial of women with overactive bladder symptoms recruited from 48 European tertiary referral centers. The participants were randomized to receive either placebo or elocalcitol, 75 μg/d or 150 μg/d for 4 weeks. A 3-day bladder diary, the Urgency Perception Scale, the Patient's Perception of Bladder Condition, and urodynamics were used before and after treatment. Vital signs, laboratory blood tests, 24-hour urine collection, and electrocardiography were also performed to assess the safety. The analysis of covariance test was used to compare the treatment groups. The primary objective was to evaluate the change in bladder volume at the first involuntary detrusor contraction from baseline.

RESULTS

A total of 308 women were studied. No significant change was seen in the urodynamic parameters between the placebo and elocalcitol groups, except for the bladder volume at the first desire to void. The frequency of incontinence episodes was significantly reduced in the elocalcitol group compared with the placebo group (P = .02). The Patient's Perception of Bladder Condition score improved significantly after treatment for the women receiving elocalcitol compared with those receiving placebo (P = .02). Treatment with both doses of elocalcitol was well tolerated, and no differences versus placebo were observed.

CONCLUSION

Although the primary endpoint was not achieved, elocalcitol appears to be an effective and well-tolerated drug for the treatment of women with overactive bladder and idiopathic detrusor overactivity. However, the multicenter setting for the use of urodynamics might have biased the results of our study.

Alterations of heart rate variability in women with overactive bladder syndrome

INTRODUCTION AND HYPOTHESIS

Our objective was to compare autonomic nervous system function between women with an overactive bladder (OAB) and control participants during regulated bladder filling.

METHODS

Twenty-four women, nine with OAB and 15 without (control), were instructed to drink 1.5 l of water at a rate of 250 ml every 5 min during continuous electrocardiogram (ECG) monitoring. Participants were asked to indicate first sensations of filling (FSF), first desire to void (FDV), strong desire to void (SDV), and maximal bladder capacity (MC). ECG signals were used to assess heart rate variability, which were analyzed in time and frequency domains using the fast Fourier transform. The low-frequency (LF)and high-frequency (HF) spectral bands were used to asses sympathetic and parasympathetic pathways, respectively.

RESULTS

During the bladder-filling phase, women with OAB had significantly lower LF values (at the MC phase 5.4 ± 1.4 ms(2)/Hz vs. 6.4 ± 0.6 ms(2)/Hz in the control group, p = 0.02). In the control group, LF increased continuously, whereas in the OAB group, LF increased until the sensation of SDV and then abruptly decreased to baseline values. MC was lower in women with OAB (372 ± 153 ml vs. 592 ± 298 ml, p < 0.05, respectively).

CONCLUSIONS

Reduced sympathetic tone in women with OAB may explain their attainment of lower volumes of MC and their sensation of urgency. The rapid decrease in sympathetic neural activity that accompanies the sensation of an SDV may be related to the pathophysiology of the urgency symptom in these women.

Sensory urgency

Overactive bladder is highly prevalent among the general population. This article describes the definition, theories of causation, diagnostic tools and various treatment options for overactive bladder.

Clinical pharmacokinetics and pharmacodynamics of solifenacin

The succinate salt of solifenacin, a tertiary amine with anticholinergic properties, is used for symptomatic treatment of overactive bladder. Solifenacin peak plasma concentrations of 24.0 and 40.6 ng/mL are reached 3-8 hours after long-term oral administration of a 5 or 10 mg solifenacin dose, respectively. Studies in healthy adults have shown that the drug has high absolute bioavailability of about 90%, which does not decrease with concomitant food intake. Solifenacin has an apparent volume of distribution of 600 L, is 93-96% plasma protein bound, and probably crosses the blood-brain barrier. Solifenacin is eliminated mainly through hepatic metabolism via cytochrome P450 (CYP) 3A4, with about only 7% (3-13%) of the dose being excreted unchanged in the urine. Solifenacin metabolites are unlikely to contribute to clinical solifenacin effects. In healthy adults, total clearance of solifenacin amounts to 7-14 L/h. The terminal elimination half-life ranges from 33 to 85 hours, permitting once-daily administration. Urinary excretion plays a minor role in the elimination of solifenacin, resulting in renal clearance of 0.67-1.51 L/h. Solifenacin does not influence the activity of CYP1A1/2, 2C9, 2D6 and 3A4, and shows a weak inhibitory potential for CYP2C19 and P-glycoprotein in vitro; however, clinical drug-drug interactions with CYP2C19 and P-glycoprotein substrates are very unlikely. Exposure to solifenacin is increased about 1.2-fold in elderly subjects and about 2-fold in subjects with moderate hepatic and severe renal impairment, as well as by coadministration of the potent CYP3A4 inhibitor ketoconazole 200 mg/day. The full therapeutic effects of solifenacin occur after 2-4 weeks of treatment and are maintained upon long-term therapy. Although solifenacin pharmacokinetics display linearity at doses of 5-40 mg, no obvious dose dependency was observed in efficacy and tolerability studies. The efficacy of solifenacin (5 or 10 mg/day) is at least equal to that of extended-release (ER) tolterodine (4 mg/day) in reducing the mean number of micturitions per 24 hours and urgency episodes, and in increasing the volume voided per micturition. Solifenacin (5 mg/day) appears to be superior to ER tolterodine (4 mg/day) in reducing incontinence episodes (mean -1.30 vs -0.90, p = 0.018) and is superior to propiverine (20 mg/day) at the dose of 10 mg/day in reducing urgency (-2.30 vs -2.78, p = 0.012) and nocturia episodes. Based on withdrawal rates due to adverse effects during the 52-week treatment period, solifenacin appears to have better tolerability than immediate-release (IR) oxybutynin 10-15 mg/day and IR tolterodine 4 mg/day. With regard to the pharmacokinetics of solifenacin, and for safety reasons, doses exceeding 5 mg/day are not recommended for patients with moderate hepatic impairment (Child-Pugh score 7-9), patients with severe renal impairment (creatinine clearance <30 mL/min) and subjects undergoing concomitant therapy with CYP3A4 inhibitors.

Pharmacologic management of urinary incontinence, voiding dysfunction, and overactive bladder

Most drugs used in the treatment of urinary incontinence and voiding dysfunction in women modulate neuromuscular transmission in the urethra and bladder. Pharmacotherapy is the mainstay of treatment for overactive bladder. Although several different antimuscarinic medications are available for the treatment of overactive bladder, most have similar efficacy and tolerability. Pharmacotherapy has a limited role in the management of stress incontinence and voiding dysfunction in women. Newer drugs that target different mechanisms of action are being developed for the treatment of urinary incontinence and voiding dysfunction in women.

Anticholinergic drugs versus other medications for overactive bladder syndrome in adults

BACKGROUND

Overactive bladder syndrome is defined as "urgency with or without urge incontinence, usually with frequency and nocturia". It is a common condition with significant economic and quality of life implications. While the condition's pathophysiology remains to be fully elucidated, pharmacotherapy is the main treatment option. Despite uncertainty as to drug treatment of choice, anticholinergics are increasingly being used in primary and secondary care settings. This review compares anticholinergic drugs with other types or classes of drugs for treating overactive bladder syndromes.

OBJECTIVES

To compare anticholinergic drugs with other types or classes of drugs for treating overactive bladder symptoms.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 20 December 2006) and the reference lists of relevant articles. No language or other limits were imposed.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials comparing anticholinergic drugs with other drugs for the treatment of overactive bladder symptoms. At least one arm of the study used an anticholinergic drug and at least one other arm used a non-anticholinergic drug.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the identified studies for eligibility and methodological quality and independently extracted data from the included studies. Data analysis was performed using RevMan software (version 4.2.8).

MAIN RESULTS

Twelve trials were included in the review. There were seven crossover trials and five parallel group studies. For the comparisons between anticholinergic drugs with tricyclic antidepressants, alpha adrenergic agonists, afferent nerve inhibitors, and calcium channel blocker a single trial was identified for each. Nine trials compared flavoxate with anticholinergics. There was no evidence of a difference in cure rates between anticholinergics and flavoxate. Adverse effects were more frequent in anticholinergic groups versus flavoxate groups (RR 2.28 95% CI 1.45 to 3.56). There was no strong evidence to favour either anticholinergic drugs or the comparators.

AUTHORS' CONCLUSIONS

Many of the drugs considered in trials in this review are no longer used in clinical practice (and this includes the most commonly tested - flavoxate). There is inadequate evidence as to determine whether any of the available drugs are better or worse than anticholinergic medications. Larger randomised controlled trials in clinical settings are required to further establish the role of these medications in the management of overactive bladder syndrome.

Anticholinergic drugs versus other medications for overactive bladder syndrome in adults

BACKGROUND

Overactive bladder syndrome is defined as "urgency with or without urge incontinence, usually with frequency and nocturia". It is a common condition with significant economic and quality of life implications. While the condition's pathophysiology remains to be fully elucidated, pharmacotherapy is the main treatment option. Despite uncertainty as to drug treatment of choice, anticholinergics are increasingly being used in primary and secondary care settings. This review compares anticholinergic drugs with other types or classes of drugs for treating overactive bladder syndromes.

OBJECTIVES

To compare anticholinergic drugs with other types or classes of drugs for treating overactive bladder symptoms.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 20 December 2006) and the reference lists of relevant articles. No language or other limits were imposed.

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials comparing anticholinergic drugs with other drugs for the treatment of overactive bladder symptoms. At least one arm of the study used an anticholinergic drug and at least one other arm used a non-anticholinergic drug.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the identified studies for eligibility and methodological quality and independently extracted data from the included studies. Data analysis was performed using RevMan software (version 4.2.8).

MAIN RESULTS

Thirteen trials were included in the review. There were eight crossover trials and five parallel group studies. For the comparisons between anticholinergic drugs with tricyclic antidepressants, alpha adrenergic agonists, afferent nerve inhibitors, and calcium channel blocker a single trial was identified for each. Ten trials compared flavoxate with anticholinergics. There was no evidence of a difference in cure rates between anticholinergics and flavoxate. Adverse effects were more frequent in anticholinergic groups versus flavoxate groups (RR 2.28 95% CI 1.45 to 3.56). There was no strong evidence to favour either anticholinergic drugs or the comparators.

AUTHORS' CONCLUSIONS

Many of the drugs considered in trials in this review are no longer used in clinical practice (and this includes the most commonly tested - flavoxate). There is inadequate no evidence as to whether any of the available is better or worse than anticholinergic medications. Larger randomised controlled trials in clinical settings are required to further establish the role of these other medications in the management of overactive bladder syndrome.

Die Therapie der Blasenüberaktivität bei älteren und alten Menschen

Overactive bladder syndrome is a widespread disorder that leads to considerable impairment of quality of life. Besides behavioural therapy (bladder training), methods used in physiotherapy, electrotherapy and instrumental biofeedback have also proved to be successful approaches to treatment. With their good clinical and urodynamic efficacy, substances with antimuscarinic action at M3 receptors in particular and possibly also at M2 receptors have proved successful as first-line agents for the treatment of overactive bladder (OAB). Despite the frequently high level of suffering and severe impairment of quality of life, however, compliance is poor. Muscarine receptors do have a significant effect on detrusor function, but numerous other mechanisms and receptor entities also play a role. Whether patient acceptance can be significantly increased by the development of selective M-receptor antagonists, improved bladder selectivity or formulating innovations remains to be proven by broad-based clinical testing and independent, comparative, scientific studies. At present, it is not possible to estimate with absolute certainty the risk of an anticholinergic-induced deterioration in cognitive abilities, in particular in elderly individuals. Initial data suggest that primarily M3-selective receptor blockage with darifenacin could be beneficial.

Pharmacokinetics, safety, and tolerability of solifenacin in patients with renal insufficiency

To evaluate the pharmacokinetics, safety, and tolerability of solifenacin in patients with mild, moderate, or severe renal disease, eighteen patients with renal disease and six healthy volunteers received a single oral dose of solifenacin (10 mg). Pharmacokinetic parameters were assessed from blood samples drawn over a 360-h period. Safety and tolerability were also evaluated. Total mean +/- S.D. exposure (ng . h/mL) to solifenacin in healthy individuals (1190 +/- 403) was increased in patients with renal disease (mild: 1784 +/- 792, moderate: 1559 +/- 555, severe: 2530 +/- 700), and elimination half-life (mean +/- S.D. [h]) was prolonged (healthy: 68.2 +/- 27.2, mild: 89.1 +/- 34.5, moderate: 90.6 +/- 27.3, severe: 111 +/- 38.3). A significant correlation was found between creatinine clearance and pharmacokinetic parameters for exposure and apparent oral clearance. No deaths or serious adverse events occurred during the study. Solifenacin 10 mg was well tolerated in patients with renal disease. Solifenacin displays a higher exposure and a prolonged half-life in patients with renal impairment, especially severe. Therefore, while no special cautions are necessary for patients with mild/moderate renal impairment, patients with severe renal impairment should receive no more than 5 mg solifenacin once daily.

Purinoceptors as therapeutic targets for lower urinary tract dysfunction

Lower urinary tract symptoms (LUTS) are present in many common urological syndromes. However, their current suboptimal management by muscarinic and alpha(1)-adrenoceptor antagonists leaves a significant opportunity for the discovery and development of superior medicines. As potential targets for such therapeutics, purinoceptors have emerged over the last two decades from investigations that have established a prominent role for ATP in the regulation of urinary bladder function under normal and pathophysiological conditions. In particular, evidence suggests that ATP signaling via P2X(1) receptors participates in the efferent control of detrusor smooth muscle excitability, and that this function may be heightened in disease and aging. ATP also appears to be involved in bladder sensation, via activation of P2X(3) and P2X(2/3) receptors on sensory afferent neurons, both within the bladder itself and possibly at central synapses. Such findings are based on results from classical pharmacological and localization studies in non-human and human tissues, knockout mice, and studies using recently identified pharmacological antagonists--some of which possess attributes that offer the potential for optimization into candidate drug molecules. Based on recent advances in this field, it is clearly possible that the development of selective antagonists for these receptors will occur that could lead to therapies offering better relief of sensory and motor symptoms for patients, while minimizing the systemic side effects that limit current medicines.

Comparison of the efficacy, safety, and tolerability of propiverine and oxybutynin for the treatment of overactive bladder syndrome

AIM

To compare the effects of propiverine and oxybutynin on ambulatory urodynamic monitoring (AUM) parameters, safety, and tolerability in patients with overactive bladder.

METHODS

This was a randomized, double-blind, placebo-controlled, multicentre, crossover study. Patients (n = 77) received two of the following treatments during two 2-week periods: propiverine 20 mg once daily, propiverine 15 mg three times daily, oxybutynin 5 mg three times daily, and placebo. AUM parameters, salivary flow, visual near point, and heart rate were assessed.

RESULTS

A consistent order in the efficacy between active treatment groups was observed for the reduction in mean involuntary detrusor contractions (IDCs; oxybutynin 15 mg </= propiverine 45 mg </= propiverine 20 mg). Differences between the oxybutynin and propiverine 20 mg groups were statistically significant for several AUM endpoints. Statistically significant differences between the oxybutynin and both propiverine groups were also noted in salivary flow rate and heart rate (oxybutynin 15 mg < both propiverine regimens) and in heart rate variability (both propiverine regimens < oxybutynin 15 mg). All active treatments lengthened visual near point. The incidence of dry mouth was significantly more pronounced in the oxybutynin group than in either propiverine group. Treatment with propiverine 45 mg resulted in the highest rates of constipation, lengthening of the visual near point, and effects on heart rate.

CONCLUSIONS

Oxybutynin 15 mg was more effective than propiverine 20 mg in reducing symptomatic and asymptomatic IDCs in ambulatory patients. The primary differences between the two drugs were the incidence and type of adverse events, which varied with the antimuscarinic receptor specificity of each agent.

Diagnosis and management of patients with overactive bladder syndrome and abnormal detrusor activity

Overactive bladder syndrome (OABS) is a widely recognized syndrome with symptoms that can include urinary urgency, frequency, nocturia, and incontinence. Although there may be several causative factors for OABS, detrusor overactivity is the most common. In addition, urinary incontinence can also be due to a distinct but equally bothersome condition underactive bladder syndrome, or detrusor underactivity. The incomplete bladder emptying that characterizes detrusor underactivity often arises from impaired contractile function of the detrusor muscle. The variations in etiologies of the two syndromes necessitate patient evaluations tailored to individual symptom presentation. Increased awareness of the differences between the manifestations of OABS and underactive bladder syndrome call for specific approaches to the management of bladder dysfunction.

Binding studies and GRIND/ALMOND-based 3D QSAR analysis of benzothiazine type K(ATP)-channel openers

For seventeen 1,4-benzothiazine potassium channel openers, we performed binding studies in rat aortic smooth muscle cells and cardiomyocytes, compared their binding affinities with published relaxation data, and derived 3D-QSAR models using GRIND/ALMOND descriptors. Binding affinities in smooth muscle cells range from a pK(D) of 4.76 for compound 3e to 9.10 for compound 4c. Comparison of data for smooth muscle relaxation and binding shows preferentially higher pEC(50)s for the former. In cardiomyocytes, pK(D) values range from 4.21 for 3e to 8.16 for 4c. 3D-QSAR analysis resulted in PLS models of two latent variables for all three activities with determination coefficients of 0.97 (smooth muscle relaxation) and 0.94 (smooth muscle cells- and cardiomyocytes-binding). Internal validation yielded q(2) values of 0.69, 0.66, and 0.64. The carbonyl on the N-4 substituent, the hydrogen bond acceptor at C-6, the five-membered ring at N-4, and the gem-dimethyls mainly guide strong binding and strong smooth muscle relaxation.

Comparison of darifenacin and oxybutynin in patients with overactive bladder: assessment of ambulatory urodynamics and impact on salivary flow

OBJECTIVES

To evaluate the effects of darifenacin, an M3 selective receptor antagonist, compared with oxybutynin, on ambulatory urodynamics, salivary flow, heart rate and visual nearpoint in patients with overactive bladder (OAB).

METHODS

A double-blind, randomized, crossover study (n=65) with three treatment cohorts: darifenacin immediate release (IR) 2.5 mg three times a day (t.i.d.) or oxybutynin 2.5 mg t.i.d.; darifenacin controlled release (CR) 15 mg once daily (q.d.) or oxybutynin 5 mg t.i.d.; darifenacin CR 30 mg q.d. or oxybutynin 5 mg t.i.d. Within cohorts, patients received 7 days' treatment with each agent separated by 14 days' washout.

RESULTS

All active treatments improved urodynamic parameters. Both darifenacin CR doses had significantly less effect on salivary flow than oxybutynin. Effects on urodynamic parameters, heart rate and visual nearpoint were comparable.

CONCLUSION

Ambulatory urodynamics appears to be an innovative and potentially useful investigative tool in the evaluation of the efficacy of new therapeutic agents. Darifenacin CR is an efficacious therapy for OAB with comparable effects on urodynamic parameters but producing significantly less dry mouth than oxybutynin.

Facilitating adherence to highly active antiretroviral therapy in children with HIV infection: what are the issues and what can be done?

Treatment of HIV infection with highly active antiretroviral therapy (HAART) requires sustained adherence to treatment to maintain efficacy. In pediatric patients, adherence to HAART represents a significant challenge for treated children and for their caregivers and healthcare providers. Many factors can affect adherence to HAART including: (i) factors related to the patient and his/her family; (ii) factors related to the drug/medication; and (iii) factors related to the healthcare system. Different strategies can be employed to tackle the specific obstacles identified in these three groups, and thus to facilitate adherence. Among the key interventions centered on the patient and his/her family are the tailoring of the HAART regimen to the daily activities of the child and his/her family, and the implementation of an intensive education program on adherence for the child and the caregiver, prior to starting the treatment. Specific medication-related problems (depending on drug pharmacokinetic and pharmacodynamic properties, taste and palatability, food interactions, etc.) exist; such problems can not be solved solely by clinicians or by families. Greater commitment of the pharmaceutical industry is needed, and innovative solutions have to be identified by clinicians in partnership with drug manufacturers. Furthermore, the development of an 'adherence strategy/program' can be recommended to all institutions working in pediatric HIV infection. Most of the necessary interventions to be included in such programs can be easily implemented, but they require trained and committed staff (and institutions), and time to be spent with patients and their caregivers.

Potassium channel subtypes as molecular targets for overactive bladder and other urological disorders

Potassium channels have re-emerged as attractive targets for overactive bladder and other urological diseases in recent years, in part due to an enhanced understanding of their molecular heterogeneity, tissue distribution, functional roles and regulation in physiological and pathological states. Cloning and heterologous expression analysis, coupled with the advancement of improved high-throughput screening techniques, have enabled expeditious identification of selective small-molecule openers and blockers for ATP-sensitive K+ channels, Ca2+-activated K+ channels and voltage-dependent K+ channel-KQT-like subfamily (KCNQ) members, and has paved the way in the assessment of efficacy and adverse effects in preclinical models. This review focuses on the rationale for molecular targeting of K+ channels, the current status of target validation, including preclinical proof-of-concept studies, and provides perspectives on the limitations and hurdles to be overcome in realising the potential of these targets for diverse urological indications such as overactive bladder, erectile dysfunction and prostate diseases.

Dose response with darifenacin, a novel once-daily M3 selective receptor antagonist for the treatment of overactive bladder: results of a fixed dose study

This study evaluated the efficacy, tolerability, and safety of darifenacin, an M3 selective receptor antagonist (M3 SRA), in patients with overactive bladder (OAB). In a multicenter, double-blind, placebo-controlled dose-ranging study, 439 adult OAB patients (85.4% female) were randomized to darifenacin controlled-release tablets 7.5 mg (n = 108), 15 mg (n = 107) or 30 mg (n = 115) qd, or placebo (n = 109) for 12 weeks. Darifenacin significantly reduced the median number of incontinence episodes/week (-68.7, -76.5, and -77.3% from baseline at 7.5, 15, and 30 mg, respectively, vs -46% with placebo, all p < 0.01) and dose relatedly improved micturition frequency, frequency and severity of urgency, nocturia, and bladder capacity. Darifenacin was well tolerated. Adverse events were commonly mild to moderate dry mouth and constipation. There were no safety concerns. Darifenacin is effective and well tolerated in the treatment of OAB, with 7.5 and 15 mg doses offering flexibility of dosing for optimal treatment outcome.

1-(2-pyrimidinyl)-piperazine, a buspirone metabolite, modulates bladder function in the anesthetized rat

AIMS

To examine the effects of 1-(2-pyrimidinyl)-piperazine (1-PP), a buspirone metabolite, on bladder function in vivo.

METHODS

Micturition reflexes in the rat were evaluated in two models of bladder function; a constant infusion model employing 0.5% acetic acid and an isovolumic model.

RESULTS

In the constant infusion model, 1-PP (0.14-1.32 mg/kg) dose-dependently and significantly decreased the number of bladder contractions measured during a 30 min recording period, with little effect on the pressure developed during each contraction. 1-PP is an alpha2-adrenergic receptor antagonist. The alpha2 antagonists BRL44408 (alpha2A vs. alpha2B selective; 0.3 and 1 mg/kg), imiloxan (alpha(2B) vs. alpha2A selective; 1 mg/kg), and yohimbine (non-subtype selective; 1 mg/kg; but not 0.3 mg/kg) also significantly reduced the number of contractions. Vehicle was without effect. In the isovolumic model, 1-PP (0.03-1.0 mg/kg) produced a dose-dependent and significant reduction in the number of bladder contractions recorded during a 15 min assessment period, with the maximum effect observed at 0.3 mg/kg. 1-PP had little effect on blood pressure; the only effect was observed at the highest dose (1 mg/kg) where it produced a transient 17% decrease in pressure. Cromakalim and tolterodine served as comparitors in all studies.

CONCLUSIONS

1-PP decreased the number of bladder contractions evoked by the micturition reflex at doses that had little effect on either the pressure developed during each bladd er contraction or on blood pressure. The effects of 1-PP are likely mediated primarily by alpha2 receptor antagonism.

KATP channel openers: structure-activity relationships and therapeutic potential

ATP-sensitive potassium channels (K(ATP) channels) are heteromeric complexes of pore-forming inwardly rectifying potassium channel subunits and regulatory sulfonylurea receptor subunits. K(ATP) channels were identified in a variety of tissues including muscle cells, pancreatic beta-cells, and various neurons. They are regulated by the intracellular ATP/ADP ratio; ATP induces channel inhibition and MgADP induces channel opening. Functionally, K(ATP) channels provide a means of linking the electrical activity of a cell to its metabolic state. Shortening of the cardiac action potential, smooth muscle relaxation, inhibition of both insulin secretion, and neurotransmitter release are mediated via K(ATP) channels. Given their many physiological functions, K(ATP) channels represent promising drug targets. Sulfonylureas like glibenclamide block K(ATP) channels; they are used in the therapy of type 2 diabetes. Openers of K(ATP) channels (KCOs), for example, relax smooth muscle and induce hypotension. KCOs are chemically heterogeneous and include as different classes as the benzopyrans, cyanoguanidines, thioformamides, thiadiazines, and pyridyl nitrates. Examples for new chemical entities more recently developed as KCOs include cyclobutenediones, dihydropyridine related structures, and tertiary carbinols.

Randomized, double-blind placebo- and tolterodine-controlled trial of the once-daily antimuscarinic agent solifenacin in patients with symptomatic overactive bladder

OBJECTIVE

To assess in a phase 3a trial the efficacy of solifenacin succinate, a once-daily oral antimuscarinic agent in development at 5-mg and 10-mg dosage strengths, for the treatment of overactive bladder (OAB) (Yamanouchi Pharmaceutical Co. Ltd, Tokyo, Japan) compared with placebo in patients with symptoms of OAB, i.e. urgency, incontinence, and frequency, with additional objectives being to assess the safety and tolerability of solifenacin and to compare the efficacy and safety of solifenacin with tolterodine 2 mg twice daily.

PATIENTS AND METHODS

The study was an international, multicentre, randomized, double-blind, tolterodine- and placebo-controlled trial conducted at 98 centres. Adult patients with symptomatic OAB for > or = 3 months were eligible; after a single-blind 2-week placebo run-in period patients were randomized equally to a 12-week double-blind treatment with either tolterodine 2 mg twice daily, placebo, solifenacin 5 mg or 10 mg once daily. Efficacy variables included change from baseline in the mean number of urgency, incontinence and urge incontinence episodes, and change from baseline in voids/24 h and mean volume voided/void.

RESULTS

In all, 1281 patients were enrolled, 1081 randomized and 1077 treated; 1033 were evaluated for efficacy. Compared with placebo, the change from baseline (-1.41, -32.7%) in the mean number of urgency episodes per 24 h was statistically significantly lower with solifenacin 5 mg (-2.85, -51.9%) and 10 mg (-3.07, -54.7%; both P < 0.001), but not with tolterodine (-2.05, -37.9%; P = 0.0511). There was a statistically insignificant decrease in episodes of incontinence with tolterodine (-1.14; P = 0.1122) but a significant decrease in patients treated with solifenacin 5 (-1.42; P = 0.008) and 10 mg (-1.45; P = 0.0038). Compared with placebo (-1.20, -8.1%) the mean number of voids/24 h was significantly lower in patients receiving tolterodine (-1.88, -15%; P = 0.0145), solifenacin 5 (-2.19, -17%) and 10 mg (-2.61, -20%; both P < 0.001). The mean volume voided/void was also significantly higher with all three active treatments (P < 0.001). Solifenacin was well tolerated; compared with placebo (4.9%), dry mouth (the most common side-effect), mostly mild, was reported in 18.6% of patients receiving tolterodine, 14.0% receiving 5 mg and 21.3% receiving 10 mg solifenacin.

CONCLUSION

Solifenacin 5 and 10 mg once daily improved urgency and other symptoms of OAB, and was associated with an acceptable level of anticholinergic side-effects. Solifenacin demonstrated significantly favourable efficacy to side-effect ratio in treating symptomatic OAB.

In vivo evaluation of the potency and bladder-vascular selectivity of the ATP-sensitive potassium channel openers (-)-cromakalim, ZD6169 and WAY-133537 in rats

OBJECTIVE

To compare in vivo the potency and bladder-vascular selectivity of ATP-sensitive potassium channel openers (KCOs) (-)-cromakalim, WAY-133537 and ZD6169 and a muscarinic antagonist, tolterodine in rats.

MATERIALS AND METHODS

Bladder and arterial pressures were monitored simultaneously, before and after increasing intravenous doses of compounds, in each of two urethane-anaesthetized rat bladder hyperactivity models: spontaneous non-voiding myogenic contractions secondary to partial outlet obstruction and volume-induced neurogenic contractions.

RESULTS

(-)-Cromakalim, WAY-133537 and ZD6169 caused a dose-dependent suppression of spontaneous contractions in the obstructed model, with a 50% inhibition of the contraction area under the curve at doses of 0.06, 0.14 and 2.4 micro mol/kg (intravenous), respectively. Corresponding decreases in mean arterial pressure at these effective doses were 24%, 15% and 15%, respectively. The KCO potency rank order was the same and their relative potency highly comparable in the neurogenic model. There was complete inhibition of spontaneous contractions in obstructed rats at doses corresponding to approximately 50% inhibition of the neurogenic contractions. While tolterodine caused a dose-dependent inhibition of contractions in the neurogenic model, it was ineffective at inhibiting non-voiding contractions in obstructed rats.

CONCLUSIONS

All KCOs tested caused significant decreases in arterial pressure at doses effective on the bladder in the model of obstructive instability, suggesting a lack of bladder-vascular selectivity. Similar KCO potency in both assays suggests no appreciable changes in KATP channel function as a result of partial outlet obstruction.

Pharmacologic management of urinary incontinence in women

This article summarizes current thought regarding the efficacy of various types of drug therapy for incontinence in women, borrowing liberally from similar previous presentations. Space limitations for this chapter necessitate some simplification and condensation of these subjects. References have generally been chosen because of their informational or review content and not because of originality or initial publication on a particular subject.

Current pharmacotherapeutic strategies for overactive bladder

Overactive bladder (OAB) is a chronic, distressing condition characterised by symptoms of urgency (sudden overwhelming urge to urinate) and frequency (urinating more than eight times daily), with or without urge urinary incontinence (sudden involuntary loss of urine). It affects millions of people of all ages and both sexes world wide, with greater prevalence in women and the elderly. The treatment of OAB is aimed at reducing debilitating symptoms, which have a significant effect on all aspects of an individual's quality of life, including social, domestic, psychological, occupational, physical and sexual functioning. Anticholinergic agents are currently recommended as first-line therapy for OAB. Their use results in significant clinical improvement in patients, although a lack of selectivity for receptors in the bladder may lead to troublesome side effects, including dry mouth, blurred vision, somnolence, dizziness and constipation. Recent research efforts have focused on developing drugs with a reduced propensity for causing these problems. Of the available anticholinergic agents, oxybutynin and tolterodine are the most widely used to treat OAB. Studies directly comparing tolterodine immediate-release (IR) with oxybutynin IR have shown that the two agents have similar efficacy. However, tolterodine IR is significantly better tolerated, particularly with respect to the incidence and severity of dry mouth. An extended-release formulation of tolterodine (4 mg capsules) has recently been developed to allow for once-daily dosing. In addition to greater convenience, tolterodine extended-release has shown enhanced efficacy and tolerability compared with tolterodine IR.

Effect of muscarinic antagonists on micturition pressure measured by cystometry in normal, conscious rats

OBJECTIVES

To establish an in vivo model to screen new muscarinic antagonists for the treatment of overactive urinary bladder and to calculate the respective ID(50) values.

METHODS

The conscious rat cystometry model was modified to determine a complete dose-response curve in each animal. Spontaneous micturition was induced by infusion of room-temperature saline into rat bladders at a constant rate of 12 mL/hr. Cumulative doses of muscarinic antagonists administered in the femoral vein caused dose-dependent inhibition of the urinary bladder contraction measured as the micturition pressure. In addition, the in vitro pK(B) values for atropine, PNU-200577 (DD01), tolterodine, oxybutynin, and terodiline were determined in carbachol-contracted rat bladder strips.

RESULTS

The rank order of the in vivo ID(50) values were atropine (14 +/- 4 nmol/kg), PNU-200577 (22 +/- 12 nmol/kg), tolterodine (94 +/- 20 nmol/kg), oxybutynin (175 +/- 89 nmol/kg), darifenacin (236 +/- 144 nmol/kg), desethyloxybutynin (313 +/- 209 nmol/kg), propiverine (4561 +/- 2079 nmol/kg), and terodiline (18,339 +/- 5348 nmol/kg). Tolterodine and PNU-200577 caused a parallel shift of the in vitro concentration-response curve to the right and did not alter the maximal contraction. The ID(50) values correlated significantly with the in vitro rat pK(B) and human bladder pA(2) values.

CONCLUSIONS

The present results suggest that the rat cystometry model can be used in in vivo screening for new muscarinic antagonists.

The overactive bladder: a nursing perspective

Symptoms of urgency and increased frequency of micturition and nocturia, with or without urge incontinence, are the hallmarks of a condition that afflicts millions of Americans. Several new drug therapies, as well as behavioral approaches, provide keys to management.

The medical benefit of 5-HT research

5-HT research is now more than 50 years old, and it has generated a wealth of therapeutic agents, some of which have had a major impact on disease management. The 5-HT reuptake inhibitors (SSRIs) are among the most widely prescribed drugs for treating depression and a variety of other disorders including anxiety, social phobia and premenstrual dysphoria (PMD). The other major success stories of 5-HT research are the discovery of 5-HT1B/D receptor agonists for treating migraine and 5-HT3 receptor antagonists for chemotherapy and radiation-induced emesis. The role of 5-HT in the mechanism of action of antipsychotic agents remains a topic of intense research, which promises better treatments for schizophrenia in the future. Compounds interacting with 5-HT1F, 5-HT2C, 5-HT6 and 5-HT7 receptors are currently under investigation and may prove to have important therapeutic applications in the future.

Vanilloid receptor ligands: hopes and realities for the future

Neurons possessing C-fibers transmit nociceptive information into the central nervous system and participate in various reflex responses. These neurons carry receptors that bind capsaicin, recently identified as the vanilloid VR1 receptor. Excitation of these cells by capsaicin is followed by a lasting refractory state, termed desensitisation, in which the neurons fail to respond to a variety of noxious stimuli. Desensitisation to capsaicin has a clear therapeutic potential in relieving neuropathic pain and ameliorating urinary bladder overactivity, just to cite 2 important examples. Vanilloids may also be beneficial in the treatment of benign prostate hyperplasia (BPH). Since the majority of elderly patients have neuropathic pain co-existent with urinary incontinence and/or BPH, a drug that ameliorates pain and improves urinary symptoms at the same time promises to be of great clinical value in geriatric medicine. In fact, capsaicin has already been shown to have a role in the treatment of conditions that can arise in the elderly, including herpes zoster-related neuropathic pain, diabetic neuropathy, postmastectomy pain, uraemic itching associated with renal failure, and urinary incontinence. The potent VR1 agonist resiniferatoxin, now in phase II clinical trials, appears to be superior to capsaicin in terms of its tolerability profile. Recent discoveries enhance the therapeutic potential of vanilloids. The recognition that VR1 also functions as a principal receptor for protons and eicosanoids implies that VR1 antagonists may be of value in the treatment of inflammatory hyperalgesia and pain. Animal experimentation has already lent support to this assumption. The discovery of VR1-expressing cells in the brain as well as in non-neural tissues such as the kidney and urothelium places VR1 in a much broader perspective than peripheral pain perception, and is hoped to identify further, yet unsuspected, indications for vanilloid therapy. The realisation that VR1 and cannabinoid CB1 receptors have overlapping ligand recognition properties may also have far-reaching implications for vanilloid therapy. In fact, arvanil, a combined agonist of VR1 and CB1 receptors, has already proved to be a powerful analgesic drug in the mouse. From academic molecular biology laboratories to industrial drug discovery centres to the clinics, there is a steady flow of new data, forcing us to constantly revise the ways we are thinking about vanilloid receptor ligands and their hopes and realities for the future. This review covers the most promising current trends in vanilloid research with special emphasis on geriatric medicine.

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.