Urodynamic and other effects of tolterodine: a novel antimuscarinic drug for the treatment of detrusor overactivity

Comprehensive overview of the available pharmacotherapy for the treatment of non-neurogenic overactive bladder in children

INTRODUCTION

Overactive bladder (OAB) is a chronic condition highly prevalent in children and causing bothersome symptoms. It is often associated with deterioration of quality of life and can be devastating for patients and their families. Prompt initiation of conservative measures should be the backbone of treatment. When conservative management fails, pharmacological options must be considered.

AREAS COVERED

Although antimuscarinics are considered the mainstay of pharmacological treatment for OAB, only two agents are currently approved for the pediatric population. Oxybutynin and propiverine are discussed in this review, as well as other non-approved antimuscarinic agents and β3-agonists with related literature to substantiate their use in children. Dual therapy along with medication adherence and persistence is also discussed.

EXPERT OPINION

The treatment of OAB in children is demanding and one must rely on a structured, stepwise approach to achieve success. Discussing conservative measures and prescribing medication is not enough. Clinicians should actively involve children and their families in the treatment, set realistic expectations, and closely monitor side effects and medication adherence to ensure maximal efficacy.

On the Absolute Stereochemistry of Tolterodine: A Circular Dichroism Study

Tolterodine (1) is a potent muscarinic receptor antagonist used in the treatment of overactive urinary bladder (OAB) syndrome. Tolterodine is chiral and it was patented, and is currently marketed, as the l-tartrate salt of the (R)-enantiomer. However, the existing literature does not offer an ultimate proof of a stereoselective mode of action of 1. A second open stereochemical issue concerns the absolute configuration (AC) of 1. Neither the original patents nor subsequent studies have established the AC of 1 in an unambiguous way, although the AC of the l-tartrate salt of 1 was assigned by X-ray diffractometry. Finally, neither electronic nor vibrational circular dichroism (ECD and VCD) spectra of 1 are reported so far. We performed a thorough ECD/VCD study of 1 in different solvents and at variable temperatures. Solvent and temperature dependence highlighted the existence of moderate flexibility which was confirmed by molecular modelling. ECD calculations with time-dependent density functional theory (TDDFT) accurately reproduced the experimental spectra and allowed us to confirm the AC of 1 in an independent way.

Mirabegron, alone and in combination, in the treatment of overactive bladder: real-world evidence and experience

Overactive bladder (OAB), the syndrome characterized by urgency, with or without urgency incontinence, usually with frequency and nocturia, in the absence of infection or other pathology, is a common, distressing and often debilitating condition with a high prevalence in the general population. For many years, the only available pharmacological treatment for OAB were the antimuscarinic agents. More recently, mirabegron, a selective agonist of the β3 adrenergic receptor, has become available. In this article we review the current evidence and experience of its use.

Tolterodine extended release in the treatment of male OAB/storage LUTS: a systematic review

Background

Overactive bladder (OAB)/ storage lower urinary tract symptoms (LUTS) have a high prevalence affecting up to 90% of men over 80 years. The role of sufficient therapies appears crucial. In the present review, we analyzed the mechanism of action of tolterodine extended-release (ER) with the aim to clarify its efficacy and safety profile, as compared to other active treatments of OAB/storage LUTS.

Methods

A wide Medline search was performed including the combination of following words: “LUTS”, “BPH”, “OAB”, “antimuscarinic”, “tolterodine”, “tolterodine ER”. IPSS, IPSS storage sub-score and IPSS QoL (International Prostate Symptom Score) were the validated efficacy outcomes. In addition, the numbers of urgency episodes/24 h, urgency incontinence episodes/24 h, incontinence episodes/24 h and pad use were considered. We also evaluated the most common adverse events (AEs) reported for tolterodine ER.

Results

Of 128 retrieved articles, 109 were excluded. The efficacy and tolerability of tolterodine ER Vs. tolterodine IR have been evaluated in a multicenter, double-blind, randomized placebo controlled study in 1529 patients with OAB. A 71% mean reduction in urgency incontinence episodes was found in the tolterodine ER group compared to a 60% reduction in the tolterodine IR (p < 0.05). Few studies evaluated the clinical efficacy of α-blocker/tolterodine combination therapy. In patients with large prostates (prostate volume >29 cc) only the combination therapy significantly reduced 24-h voiding frequency (2.8 vs. 1.7 with tamsulosin, 1.4 with tolterodine, or 1.6 with placebo). A recent meta-analysis evaluating tolterodine in comparison with other antimuscarinic drugs demonstrated that tolterodine ER was significantly more effective than placebo in reducing micturition/24 h, urinary leakage episodes/24 h, urgency episodes/24 h, and urgency incontinence episodes/24 h. With regard to adverse events, tolterodine ER was associated with a good adverse event profile resulting in the third most favorable antimuscarinic. Antimuscarinic drugs are the mainstay of pharmacological therapy for OAB / storage LUTS; several studies have demonstrated that tolterodine ER is an effective and well tolerated formulation of this class of treatment.

Conclusion

Tolterodine ER resulted effective in reducing frequency urgency and nocturia and urinary leakage in male patients with OAB/storage LUTS. Dry mouth and constipation are the most frequently reported adverse events.

Onset of action of the β3-adrenoceptor agonist, mirabegron, in Phase II and III clinical trials in patients with overactive bladder

Purpose

Long-term persistence with pharmacotherapy for overactive bladder (OAB) requires a drug with an early onset of action and good efficacy and tolerability profile. Although antimuscarinics improve OAB symptoms within 1–2 weeks of initiating treatment, adherence after 3 months is relatively poor due to bothersome side effects (e.g., dry mouth and constipation). Mirabegron, a β₃-adrenoceptor agonist, has demonstrated significant improvements in key symptoms of OAB and good tolerability after 12 weeks in Phase III studies.

Methods

This was a prespecified pooled analysis of three randomized, double-blind, placebo-controlled, 12-week studies, and a Phase II study, to evaluate efficacy and tolerability of mirabegron 25 and 50 mg versus placebo. The main efficacy endpoints were change from baseline to week 1 (Phase II only), week 4, and final visit in mean number of incontinence episodes/24 h, micturitions/24 h, and mean volume voided/micturition (MVV).

Results

A significant benefit for mirabegron 25 and 50 mg versus placebo was evident at the first assessment point, 4 weeks after initiation of therapy, in Phase III studies for incontinence, micturitions, and MVV. The earliest measured benefit was after 1 week, in the Phase II study. Quality-of-life parameters also significantly improved with mirabegron 25 and 50 mg as early as week 4. Significant benefits continued throughout the studies. Mirabegron was well tolerated.

Conclusions

The early onset of action and good overall efficacy and tolerability balance that mirabegron offers may lead to high rates of persistence with mirabegron in the long-term treatment of OAB.

Management of mixed urinary incontinence

Mixed urinary incontinence accounts for 33% of all incontinence and is the involuntary loss of urine associated with the sensation of urgency; it is also associated with exertion, sneezing or coughing. Risk factors include vaginal delivery, obesity, age and possible genetic factors. Treatment includes lifestyle changes, behavioral therapies, medication and nerve modulation. Surgery with midurethral slings can cure both stress and urge components in 40-50% of cases. Future therapies may include new medications adapting potassium and calcium channels and more widespread use of sacral neuromodulation. This review focuses on the investigation and optimal management of mixed urinary incontinence.

Evaluation of an experimental urodynamic platform to identify treatment effects: a randomized, placebo-controlled, crossover study in patients with overactive bladder

AIMS

To evaluate a urodynamic platform designed to identify treatment effects in small numbers of patients after a short duration of treatment using a medication with known efficacy in overactive bladder (OAB).

METHODS

Twenty women with OAB were randomized in a crossover study with 7-day treatment periods with either tolterodine 4 mg long-acting (LA) or placebo and 7-day washout. Patients underwent urodynamic study (UDS) at baseline, 4-hr post-dose on Day 1 (PD1) and 4 hr post-dose on Day 7 (PD7) in each treatment period. The primary endpoint was the change from baseline in volume at maximum cystometric capacity (MCC) at PD7. As a result of dosing errors, some patients allocated to tolterodine in Period 1 mistakenly received placebo on Day 7. The data from the time points at which patients were dosed incorrectly were excluded from the per protocol (PP) analysis.

RESULTS

The PP and intent to treat (ITT) mean increase in volume at MCC on PD7 for tolterodine compared with placebo was 28.9% (P = 0.038, one-sided) and 23.2% (P = 0.008, one-sided), respectively. The PD7 mean increase in volume at first desire to void was 36.5% (P = 0.054, PP) and 40.3% (P = 0.008, ITT). No volume endpoint at PD1 was statistically significant. Of all the endpoints, MCC was the least variable.

CONCLUSIONS

This crossover design was able to detect a clinically meaningful and statistically significant treatment effect consistent with the previous reports of tolterodine. Despite multiple urodynamics per patient, the study was able to recruit quickly. This model is valuable for evaluating therapeutic effects for existing and novel treatments for OAB.

Comparative analysis of the effects of antimuscarinic agents on bladder functions in both nonhuman primates and rodents

Both the physiological role of muscarinic receptors for bladder function and the therapeutic efficacy of antimuscarinic agents for overactive bladder syndrome are well documented. We investigated the effect of antimuscarinic agents with different subtype selectivity on urodynamic parameters in nonhuman primates and rodents and compared plasma levels of these agents between species. Anesthetized rhesus monkeys were transurethrally catheterized, and the bladder was infused with saline. Urodynamic parameters were measured before and after intravenous drug administration. Tolterodine (nonselective) and oxybutynin (moderately M(3)-selective) increased bladder capacity at lower doses than those required to decrease micturition pressure. However, higher doses of darifenacin (M(3)-selective) were needed to increase the bladder capacity than those needed to decrease the micturition pressure. In rats, tolterodine had no effect on the bladder capacity but decreased the micturition pressure at all of the doses administered. Oxybutynin also decreased micturition pressure and increased bladder capacity at the highest dose. Plasma levels of these drugs overlap in both species. These results suggest that, in addition to the M(3) receptor, other muscarinic receptor subtypes contribute to regulate bladder storage function in nonhuman primates, since less subtype-selective tolterodine and oxybutynin showed higher specificity to the bladder capacity effect than the effect on micturition pressure compared with M(3)-selective darifenacin. In addition, the role of muscarinic receptors in bladder storage function varies between primates and rodents. Compared with rodents, muscarinic receptors may play a more active role during the storage phase to regulate the functional bladder capacity in primates.

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.

Detrusor overactivity: an overview

Detrusor overactivity (DO) is a common clinical problem having profound effects on the quality of life (QOL) of women. With the use of meshes in the antiincontinence surgery, a new onset of DO, de novo DO has become an important issue in postoperative QOL of women. A systematic review of English language literature was conducted from Pubmed and publications of the last 7 years were analyzed and presented in this review. Multiple pathological events in the urothelium, sub-urothelium and possibly in the detrusor muscle seem to underlie the pathophysiology of DO. A variety of approaches, from life style modification to minimal-invasive surgery are available to treat DO and it is the responsibility of the physician to properly select and apply these modalities with the ultimate aim in improving the QOL of the patients. It is imperative to know the various pathophysiological processes that underlie the causation of DO to select proper management approach.

Tolterodine extended-release for overactive bladder

Overactive bladder (OAB) is a common problem. Affected individuals suffer decreased quality of life and productivity. The mainstay of pharmacological treatment of OAB is antimuscarinic agents. Tolterodine was the first antimuscarinic drug designed specifically for treating OAB. Compared with the immediate-release (IR) drug, once-daily tolterodine extended-release (ER) releases the drug in a steady but constant manner lowering peak and trough drug levels. This translates to more constant serum concentrations and theoretically better patient tolerability. The dry mouth rate for the ER formulation has been reported to be lower than for the IR formulation. Recent literature strongly supports the efficacy and safety of tolterodine ER in carefully selected older men with OAB symptoms. Tolterodine ER is well tolerated and withdrawal rates are similar to those in placebo. Fesoterodine is a new antimuscarinic that shares the same active metabolite as tolterodine and may provide less pharmacokinetic variability. We support tolterodine ER for treating for OAB. It has proven efficacy and tolerability.

Tolterodine for the treatment of overactive bladder

BACKGROUND

The overactive bladder syndrome is a common condition affecting approximately 12% of men and women. It is extremely disturbing with a great impact on quality of life. Its treatment involves a combination of behavioural and pharmacological therapy. The latter includes antimuscarinic drugs such as tolterodine.

OBJECTIVE

To review the safety and efficacy of tolterodine in the treatment of overactive bladder in comparison with other available antimuscarinic agents.

METHODS

A Pubmed search was carried out differentiating randomised, clinical trials; longitudinal, retrospective studies; and metanalysis on the use of tolterodine for overactive bladder treatment. In the comparison with other antimuscarinic agents, only randomised, clinical trials were considered.

RESULTS/CONCLUSION

Tolterodine is available as immediate- or extended-release formulations. It has been extensively evaluated with long-term, randomised trials for safety and efficacy showing a significant improvement in overactive bladder symptoms with an excellent tolerability profile.

Current and emerging investigational medical therapies for the treatment of overactive bladder

Overactive bladder (OAB) is a chronic distressing condition characterised by urinary urgency with or without urge incontinence, usually with frequency (voiding at least eight times daily) and nocturia. It affects millions of people worldwide independent of age, sex and race. The prevalence increases with age and is relatively higher in women compared with men. The treatment of OAB is aimed at reducing the debilitating symptoms so as to improve the overall quality of life for patients. Anticholinergic agents targeting the muscarinic receptors in the bladder represent the mainstay of pharmacotherapy for the treatment of OAB. Besides their status as the current standard of care, use of antimuscarinic drugs is limited by certain side effects, particularly dry mouth and constipation; therefore, various attempts have been made to improve the organ selectivity of these drugs to overcome the side effects. These include the development of new antimuscarinic agents with structural modifications and the use of innovative drug delivery methods. The advancement in the drug delivery systems extends to the long-term therapeutic efficacy with improved tolerability and patient compliance; however, future prospective therapies are aimed at novel targets with novel mechanisms of action, including beta3-adrenoceptor agonists, K+ channel openers, 5-HT modulators and botulinum toxin, which are currently under different stages of clinical development. Among other investigational therapies, neurokinin receptor antagonists, alpha-adrenoceptor antagonists, nerve growth factor inhibitors, gene therapy and stem cell-based therapies are of considerable interest. The future for the development of new modalities for the treatment of OAB looks promising.

Solifenacin provides effective antimuscarinic therapy for the complete management of overactive bladder

Solifenacin is an antimuscarinic agent, administered once daily, which has been newly approved for the treatment of overactive bladder (OAB). Solifenacin administered at 5- and 10-mg once-daily doses shows efficacy for all the symptoms of OAB in both 'wet' and 'dry' patients, including improvements in patient quality of life and satisfaction. These improvements are observed as early as week 2 of treatment and are maintained over 12-week and 1-year time periods, without being compromised by the age or gender of the patient. Solifenacin demonstrates a favourable tolerability profile, with mild dry mouth as the most common adverse event associated with its use, both at the 5- and 10-mg doses; this allows for flexibility in the dosing regimen, in which physicians can administer solifenacin 5 mg, with the option to safely increase the dose to 10 mg if necessary based on the severity of patient's symptoms. The favourable efficacy and safety profile of solifenacin, coupled with its dose flexibility, are consistent with solifenacin being a convenient treatment option for patients with OAB.

Tolterodine for Treatment of Overactive Bladder

Tolterodine was developed as an antimuscarinic agent specifically for the treatment of overactive bladder. Initial in vivo studies demonstrated a functional selectivity for the muscarinic receptors in the urinary bladder over the salivary glands, and subsequent clinical trials showed an overall superior tolerability profile compared with other drugs in the same class (ie, oxybutynin). With immediate- and extended-release formulations and sustained clinical efficacy during long-term treatment, tolterodine gas become an important treatment option for the symptoms of overactive bladder.

Urodynamic effects of oxybutynin and tolterodine in conscious and anesthetized rats under different cystometrographic conditions

Background

Antimuscarinic agents are the most popular treatment for overactive bladder and their efficacy in man is well documented, producing decreased urinary frequency and an increase in bladder capacity. During cystometry in rats, however, the main effect reported after acute treatment with antimuscarinics is a decrease in peak micturition pressure together with little or no effect on bladder capacity. In the present experiments we studied the effects, in rats, of the two most widely used antimuscarinic drugs, namely oxybutynin and tolterodine, utilising several different cystometrographic conditions. The aim was to determine the experimental conditions required to reproduce the clinical pharmacological effects of antimuscarinic agents, as seen in humans, in particular their ability to increase bladder capacity.

Results

Intravenous or oral administration of tolterodine or oxybutynin in conscious rats utilized 1 day after catheter implantation and with saline infusion at constant rate of 0.1 ml/min, gave a dose-dependent decrease of micturition pressure (MP) with no significant change in bladder volume capacity (BVC). When the saline infusion rate into the bladder was decreased to 0.025 ml/min, the effect of oral oxybutynin was similar to that obtained with the higher infusion rate. Also, experiments were performed in rats in which bladders were infused with suramin (3 and 10 μM) in order to block the non-adrenergic, non-cholinergic component of bladder contraction. Under these conditions, oral administration of oxybutynin significantly reduced MP (as observed previously), but again BVC was not significantly changed.

In conscious rats with bladders infused with diluted acetic acid, both tolterodine and oxybutynin administered at the same doses as in animals infused with saline, reduced MP, although the reduction appeared less marked, with no effect on BVC.

In conscious rats utilized 5 days after catheter implantation, a situation where inflammation due to surgery is reduced, the effect of tolterodine (i.v.) and oxybutynin (p.o.) on MP was smaller and similar, respectively, to that observed in rats utilized 1 day after catheter implantation, but the increase of BVC was not statistically significant.

In anesthetized rats, i.v. administration of oxybutynin again induced a significant decrease in MP, although it was of questionable relevance. Both BVC and threshold pressure were not significantly reduced. The number and amplitude of high frequency oscillations in MP were unmodified by treatment.

Finally, in conscious obstructed rats, intravenous oxybutynin did not modify frequency and amplitude of non-voiding contractions or bladder capacity and micturition volume.

Conclusion

Despite the different experimental conditions used, the only effect on cystometrographic parameters of oxybutynin and tolterodine in anesthetized and conscious rats was a decrease in MP, whereas BVC was hardly and non-significantly affected. Therefore, it is difficult to reproduce in rats the cystometrographic increase in BVC as observed in humans after chronic administration of antimuscarinic agents, whereas the acute effects seem more similar.

Update on the role of anticholinergic drug therapy in the management of overactive bladder

OBJECTIVE

To review the published literature and describe the pathophysiology and management of overactive bladder (OAB), with emphasis on the comparative efficacy and adverse event profiles of anticholinergic agents approved for the management of OAB symptoms and evaluation of their place in therapy.

DATA SOURCES

A MEDLINE search of English language literature that addresses the pathophysiology and management of OAB symptoms. The references in identified articles were evaluated for additional relevant articles. Drug Topics' Red Book was referenced for cost comparisons, and package inserts were used for specific drug and dosing information.

STUDY SELECTION

Human studies that presented efficacy and safety data with respect to anticholinergic medications in the treatment of OAB were selected.

DATA EXTRACTION

Studies were abstracted to identify key characteristics with respect to efficacy and safety in OAB, in particular anticholinergic side effects, with the greatest weight given to studies that compared two or more anticholinergic medications.

DATA SYNTHESIS

Epidemiologic studies have shown that the unpredictable and bothersome symptoms associated with OAB occur in approximately 16% of the worldwide adult population. Conservative management of OAB should include a combination of pharmacologic and nonpharmacologic interventions that have been found to improve outcomes when used in appropriately selected patients. Although long recognized as the most effective pharmacotherapy for OAB, anticholinergic agents have been associated with poor tolerability attributable to anticholinergic adverse events. New medications, formulations, and drug delivery systems have been developed with the goal of achieving effective treatment with improved tolerability.

CONCLUSIONS

Among these agents, extended-release and transdermal formulations have improved tolerability while retaining at least comparable efficacy. More research is needed regarding other routes of administration and new drug entities that specifically target the pathologic mechanisms involved in OAB.

Tolterodine: a new antimuscarinic agent for the treatment of the overactive bladder

Bladder hyperactivity is a debilitating problem that affects many individuals. A plethora of therapeutic options have been investigated to combat this condition, antimuscarinic therapy being the most widely used. Nevertheless, this medication group has historically been of limited benefit, due to its side-effect profile. Tolterodine is a new muscarinic receptor antagonist that has been shown to be equally effective when compared to oxybutynin. However, the side-effect profile for tolterodine is much better than this commonly used anticholinergic. It has reduced affinity for the salivary glands in animal studies, and, in clinical trials, there has been a reduced incidence of dry mouth with this medication. In Phase III studies, tolterodine has been shown to decrease the number of micturitions per day, decrease the number of incontinence episodes per day and increase the mean volume voided per micturition. The maximal effect of this medication may not be seen for 6 - 8 weeks after initiation of the drug although the exact explanation for this finding has yet to be completely elucidated. The recommended dose is 2 mg b.i.d., which should be adjusted for those with liver failure or those on drugs that inhibit the cytochrome P450 isoenzyme known as CYP3A4. In summary, tolterodine is an effective well-tolerated antimuscarinic which should be considered as a first-line treatment due to its more favourable side-effect profile when than other available medications.

Urinary urge incontinence: causes and management strategies

Bladder control is a skill most people learn in childhood, so if control is lost in adult life the impact can be very significant, particularly on the quality of life of the person affected. There are many causes of loss of bladder control, ranging from neurological conditions to menopause, as well as certain medications. This article discusses urinary urgency and urge incontinence, examines its causes and diagnosis, and provides an overview of the nursing interventions available to treat the problem.

Antimuscarinics for treatment of overactive bladder

For many years, antimuscarinic drugs have been the first-line pharmacological treatment for urgency, frequency, and urge incontinence, all symptoms of the disorder termed overactive bladder. Antimuscarinic treatment is not always effective and is associated with side-effects that limit its clinical use. The clinical significance of the effects of antimuscarinic drugs has been questioned lately. In this review, the rationale for the use of these drugs in the management of overactive bladder is re-examined and the results of treatment are discussed. I conclude that these drugs are the only treatment with undisputed effectiveness in the treatment of overactive bladder. They may not be the perfect treatment for all patients with this disorder, but their value for individual patients should not be underestimated. Further clinical trials with improvement in quality of life as the primary endpoint are needed and may give a fair reflection of the clinical value of antimuscarinic drugs.

[Overactive bladder--treatment with antimuscarinic agents]

Today, urgency and urge incontinence are both defined under the topic overactive bladder (OAB) whereby pure urge syndrome (pollakisuria, nocturia, and urgency) can easily lead to urge incontinence. Antimuscarinics still constitute the domain of treatment for overactive bladder. The pharmacological effect of modern substances consists of M2 or M3 muscarinic receptor blockade. This blockade prevents acetylcholine from connecting to these receptors and thus leads to a weakness or prevention of the detrusor muscle contraction. These groups of drugs are defined as muscarinic receptor antagonists, antimuscarinics, or anticholinergics. In addition to the muscarinic receptors, some drugs directly block the calcium channels in the cell membrane (calcium antagonists) which are classified as drugs with mixed effect. The presented paper gives an overview about the existing data on drugs approved in Germany whose clinical effect has been proven in randomized studies or are have stood the test of time in daily clinical practice.

The use of tolterodine in children after oxybutynin failure

OBJECTIVE

To assess the safety and efficacy of tolterodine tartrate prescribed to children who previously failed to tolerate oxybutynin chloride.

PATIENTS AND METHODS

We reviewed 34 children, followed for>1 year, who were prospectively crossed-over from oxybutynin to tolterodine because of side-effects. The initial diagnosis was dysfunctional voiding in 31 patients. All patients were placed on a behavioural modification protocol. When their symptoms did not improve after 6 months, treatment with an anticholinergic agent was considered. Urodynamic studies were conducted in 20 patients, confirming uninhibited contractions in 19. The remaining 14 patients were empirically started on antimuscarinic or anticholinergic agents. The 34 patients were treated with oxybutynin for a median (range) of 6 (2-84) months. When significant side-effects were reported, they were crossed over to tolterodine. The efficacy of tolterodine was assessed as defined by the International Children's Continence Society, with tolerability assessed and side-effects documented using a questionnaire.

RESULTS

The mean age at the first dose of tolterodine was 8.9 years; the dose was 1 mg twice daily for 12 patients and 2 mg twice daily for 22. The median treatment with tolterodine was 11.5 months, with 20 (59%) patients reporting no side-effects; six described the same but tolerable side-effects as with oxybutynin. Eight patients discontinued tolterodine because of side-effects after a median (range) of 5 (1-11) months. The efficacy of tolterodine was comparable with that of oxybutynin, as reported by the questionnaire and voiding diaries. The reduction in wetting episodes at 1 year was> 90% in 23 (68%), more than half in five and less than half (or failure) in six patients.

CONCLUSION

Tolterodine is tolerated well in children. In this subgroup of patients who could not tolerate oxybutynin, 77% were able to continue tolterodine treatment with no significant side-effects.

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.

Tolterodine: selectivity for the urinary bladder over the eye (as measured by visual accommodation) in healthy volunteers

OBJECTIVE

Tolterodine exhibits a favourable selectivity for the urinary bladder over salivary glands in vivo, in the anaesthetised cat, whereas oxybutynin shows the opposite selectivity profile in this model. This study further evaluated the selectivity profiles of tolterodine and oxybutynin by comparing the effects on bladder function and visual accommodation in the same individuals.

METHODS

In a double-blind, randomised, four-way crossover study, 16 healthy volunteers received single oral doses of tolterodine 5 mg and oxybutynin 2.5, 5 and 7.5 mg. Voiding parameters were assessed for 12 hours post-dose, along with visual accommodation (near point of vision) at regular intervals.

RESULTS

A dose-dependent increase in maximum bladder capacity was observed for oxybutynin [2.5 mg (+35%), 5 mg (+45%) and 7.5 mg (%)]. The effect of tolterodine 5 mg on bladder capacity was approximately twice (+93%) that seen after oxybutynin 5 mg and the onset of the effect was more rapid with tolterodine. Effects on visual accommodation were also dose-dependent for oxybutynin (maximum changes in near point of vision were 13%, 20% and 29%, respectively). The maximum change observed after tolterodine 5 mg was the same as after oxybutynin 5 mg (i.e. 20%).

CONCLUSIONS

Tolterodine seems to exhibit selectivity for the bladder over the eye. Therefore, these results suggest that the normal dosage of tolterodine (2 mg twice daily) may have less effect on visual accommodation than the equivalent dosage of oxybutynin (5 mg three times daily) in patients with an overactive bladder.

Pharmacologic treatment for detrusor overactivity

Recent pharmacologic treatment for detrusor overactivity has resulted in more favorable side effect profiles, not only because of the use of different drug delivery systems for older drugs but perhaps also due to the improved bladder selectivity of newer antimuscarinic agents. These developments translate into higher patient compliance and better long-term results with the newer agents over generic immediate-release oxybutynin for the treatment of the overactive bladder.

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.

Long-term safety, tolerability and efficacy of extended-release tolterodine in the treatment of overactive bladder

BACKGROUND

The objective of the present study was to examine the long-term safety, tolerability and efficacy of tolterodine extended-release (ER) in patients who had completed 12 weeks' treatment in a randomised, double-blind study comparing tolterodine ER 4 mg once daily (qd), tolterodine immediate-release (IR) 2mg twice daily and placebo.

METHODS

Of the 1377 patients completing the 12-week study, a total of 1077 (78%) chose to continue with 12 months' open-label treatment with tolterodine ER 4 mg once daily, irrespective of their previous treatment. Safety was assessed after 3, 6, 9 and 12 months' treatment in the study. Efficacy was evaluated from micturition diary variables and patients' perception of bladder condition and urgency following 3 and 12 months' treatment.

RESULTS

71% of patients completed the 12-month study. Tolterodine ER was safe and well tolerated. Adverse events of the general (14.5%), autonomic (13.2%), gastrointestinal (11.4%), respiratory (9.8%) and urinary (9.1%) systems were the most frequently reported. Dry mouth was the most common event, occurring in 12.9% of patients, and was generally mild in severity. Other adverse events occurred in less than 5% of patients. There was no increase in the frequency of adverse events with long-term relative to short-term treatment. The efficacy of tolterodine was maintained over the 12-month treatment period; relative to baseline there were reductions in the number of incontinence episodes per week (median change -83%) and micturitions per 24 hours (median change -21%) and an increase in volume voided (median change +25%) after 12 months' treatment. An improvement in patient perception of their bladder condition was found in 75% of patients completing the study, and 51% had an improvement in patient perception of urgency.

CONCLUSIONS

Tolterodine ER 4mg qd displayed a favourable safety, tolerability and efficacy profile during 12 months' treatment of patients with overactive bladder.

Tolterodine: as effective but better tolerated than oxybutynin in Asian patients with symptoms of overactive bladder

BACKGROUND

This double-blind, multicenter study compared the efficacy and tolerability of tolterodine (Pharmacia, Los Angeles, USA) with that of oxybutynin (Alza, Palo Alto, USA) in Asian patients with overactive bladder.

METHODS

Two-hundred-and-twenty-eight adults with overactive bladder symptoms were randomized to receive tolterodine 2 mg twice daily (bid) (n = 112) or oxybutynin 5 mg bid (n = 116). After 8 weeks' treatment, changes in micturition diary variables, patients' perception of treatment benefit, and tolerability endpoints were determined.

RESULTS

The mean (+/- SD) number of micturitions/24 h decreased by 2.6 +/- 2.9 (-21%) with tolterodine and 1.8 +/- 4.2 (-15%) with oxybutynin (both P = 0.0001 vs baseline). The mean number of incontinence episodes/24 h decreased by 2.2 +/- 2.3 (-85%) in the tolterodine group and by 1.4 +/- 1.8 (-58%) in the oxybutynin group (both P = 0.0001 vs baseline). Patient perception of treatment benefit was over 70% in each treatment group. Adverse events were significantly lower in the tolterodine group compared with oxybutynin-treated patients (55% vs 82%; P = 0.001). Dry mouth was reported by significantly fewer patients on tolterodine, compared with oxybutynin (35% vs 63%; P = 0.001) and withdrawals due to adverse events were lower in the tolterodine group than with those treated with oxybutynin (10% vs 16%). There were no safety concerns.

CONCLUSIONS

Tolterodine 2 mg bid is equally or more effective than oxybutynin 5 mg bid in the treatment of Asian patients with overactive bladder, and shows significantly better tolerability. This may enhance compliance during long-term treatment.

Tolterodine and its active 5-hydroxymethyl metabolite: pure muscarinic receptor antagonists

Tolterodine and its major active 5-hydroxymethyl metabolite (5-HM) are potent muscarinic receptor antagonists that show selectivity for the urinary bladder over salivary glands in vivo. This tissue selectivity cannot be attributed to muscarinic receptor subtype selectivity, since both compounds are non-selective with respect to the M1-M5 receptor subtypes. The aim of the present in vitro study was to determine the specificity of tolterodine and 5-HM for muscarinic receptors compared to other potential cellular targets. Carbachol-induced contractions of isolated guinea pig bladder were effectively inhibited by tolterodine (IC50 14 nM) and 5-HM (IC50 5.7 nM). Tolterodine and 5-HM were weak inhibitors of effects mediated by alpha-adrenergic receptors (rat portal vein), histamine receptors (guinea pig ileum) and calcium channels (guinea pig potassium-depolarised urinary bladder, spontaneously beating right atria and electrically-driven right papillary muscle). The IC50 values were in the microM range and the antimuscarinic potency of tolterodine was 27, 200 and 370-485 times higher, respectively, than its potency in blocking histamine receptors, alpha-adrenoceptors and calcium channels. The active metabolite, 5-HM, was >900 times less potent at these sites than at bladder muscarinic receptors. Radioligand binding data on 54 different receptors and binding sites showed that tolterodine and 5-HM bind with significant affinity only at muscarinic receptors. In conclusion, the results of the present study indicate that both tolterodine and 5-HM are specific muscarinic receptor antagonists. The tissue selectivity of these agents in vivo cannot therefore be explained by secondary pharmacological actions.

A multicenter, prospective, open-label study of tolterodine extended-release 4 mg for overactive bladder: the speed of onset of therapeutic assessment trial (STAT)

BACKGROUND

Antimuscarinic agents are the primary treatment for overactive bladder (OAB), but there is a lack of information regarding when maximum symptom relief and maximum perceived patient benefit occur.

OBJECTIVE

This study assessed the speed of onset of therapeutic benefit with tolterodine extended-release (ER) 4 mg.

METHODS

This 12-week, multicenter, prospective, open-label study enrolled patients with OAB who either had received no previous pharmacologic treatment for OAB (drug naive) or were receiving such treatment at enrollment (previously treated). Efficacy was assessed at 1, 4, and 12 weeks using a micturition diary and measures of patients' and physicians' perceptions of improvement. Safety was assessed in terms of adverse events and study withdrawals.

RESULTS

The intent-to-treat population included 1138 patients (302 men, 836 women; 88.4% white; age range, 18-91 years), 735 drug naive and 403 receiving treatment for OAB at enrollment. After 1 week, tolterodine ER 4 mg had produced a significant improvement in all efficacy variables in both groups of patients (P < 0.01); 72% of the maximum effect on urge incontinence was observed in both groups; and 84.7% of drug-naive patients and 83.6% of previously treated patients perceived a benefit from treatment. After 4 weeks, drug-naive and previously treated patients reported a respective 93% and 100% of the maximum effect on episodes of urge incontinence. Tolterodine was well tolerated, with dry mouth (mostly mild) the most commonly reported adverse event (15.5% in each group). The 330 (81.9%) patients who had reported unacceptable efficacy and the 87 (21.6%) patients who had reported unacceptable tolerability of previous OAB treatment responded favorably to tolterodine ER 4 mg.

CONCLUSIONS

Tolterodine ER 4 mg was effective and well tolerated in both drug-naive and previously treated patients with OAB. More than 80% of patients reported benefit from treatment after 1 week, but maximum symptom relief was achieved with longer treatment.

Twelve-month treatment of overactive bladder: efficacy and tolerability of tolterodine

CONTEXT

Tolterodine is a bladder-selective antimuscarinic agent designed for the treatment of overactive bladder. Traditional antimuscarinic therapies are poorly tolerated due to a high incidence of anticholinergic adverse events and consequently few patients remain on long term therapy.

OBJECTIVE

To evaluate the long term efficacy and tolerability of tolterodine in patients with symptoms of overactive bladder.

DESIGN

Twelve-month open-label extension of 4 randomised, placebo-controlled, double-blind, multinational, multicentre trials of 4 weeks' duration.

PATIENTS

714 patients (aged 18 to 92 years) with symptoms of overactive bladder who completed the double-blind portion of the studies.

INTERVENTION

Tolterodine 2 mg twice daily for up to 12 months.

MAIN OUTCOME MEASURES

Micturition diary variables: number of micturitions per 24 hours, number of urge incontinence episodes per 24 hours, mean urine volume voided per micturition. Safety variables: adverse events, study discontinuation rate.

RESULTS

A total of 441 patients (62%) completed 12 months' open-label treatment with tolterodine, which significantly reduced the number of micturitions per 24 hours [mean change -2.4, 95% confidence interval (CI) -2.7 to -2.2, median change -20%, p < 0.0001] and number of urge incontinence episodes per 24 hours (mean change -1.3, 95% CI -1.6 to -1.0, median change -74%, p < 0.0001), while the mean volume voided per micturition was significantly increased (+33 ml, 95% CI +28 to +38, median change +18%; p < 0.0001). 41% of patients reported dry mouth (27% mild, 10% moderate, 3% severe). Dosage reduction to 1 mg twice daily was required in 23% of patients. 15% of patients withdrew from the study due to adverse events, with 5% having associated dry mouth.

CONCLUSIONS

The high percentage of patients completing 12 months' treatment indicates that tolterodine is an effective and well tolerated agent for long term treatment of overactive bladder.

Urinary antispasmodic use and the risks of ventricular arrhythmia and sudden death in older patients

OBJECTIVES

The introduction of new medications to treat overactive bladder has resulted in a significant increase in the number of individuals with this condition who use medications for symptoms. Formal epidemiological studies of the safety of these medications in typical patient populations are lacking, particularly studies of serious events. We sought to determine whether the use of urinary antispasmodics increases the risk of ventricular arrhythmias or sudden death.

DESIGN

Retrospective cohort study.

SETTING

Retrospective analysis of data of participants in community, hospital or nursing home setting.

PARTICIPANTS

Fourteen thousand six hundred thirty-eight subjects with a diagnosis of urinary incontinence made between January 1, 1991, and June 30, 1995; all were aged 65 and older and enrolled in Medicare and Medicaid or the Pharmacy Assistance for the Aged and Disabled programs of New Jersey.

MEASUREMENTS

Filled prescriptions for oxybutynin (Ditropan), flavoxate (Urispas), hyoscyamine (Cystospas), and hyoscyamine sulfate (Cystospas-M) were used to define days of exposure to these drugs. We also identified all use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors, and their concurrent use, to serve as a positive control exposure. Two outcomes were then defined: a new diagnosis of ventricular arrhythmia combined with initiation of an antiarrhythmic medication and sudden death. Other covariates, including clinical, demographic, medication use, and healthcare utilization variables, were also assessed. Adjusted risk ratios of ventricular arrhythmia and sudden death were derived from multivariable Cox proportional hazards models.

RESULTS

There was no significant association between periods of use of urinary antispasmodics and the development of ventricular arrhythmias (adjusted risk ratio (RR) = 1.23, 95 confidence interval (CI) = 0.87-1.75) or sudden death (adjusted RR = 0.70, 95% CI = 0.28-1.74). A significantly increased risk of ventricular arrhythmia was observed for the positive control regimen, concurrent use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors (adjusted RR = 5.47; 95% CI = 1.34-22.26), but not for use of either drug group alone. Concurrent use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors was also associated with a significant increase in the risk of sudden death (adjusted RR = 21.50, 95% CI = 5.23-88.37). Other variables significantly associated with ventricular arrhythmia included ischemic heart disease and congestive heart failure, whereas nursing home use before the index date was associated with a decreased likelihood of receiving a diagnosis of and treatment for ventricular arrhythmia. Other variables significantly associated with sudden death included male gender, black race, and congestive heart failure.

CONCLUSIONS

Antimuscarinic urinary antispasmodics available before 1996 were not associated with an increased risk of ventricular arrhythmias and sudden death. Additional study will be required to confirm these results, exclude the possibility of unmeasured confounders contributing to any lack of an observed relationship, and extend these findings to newer agents such as tolterodine.

Tolterodine: a review of its use in the treatment of overactive bladder

Tolterodine is a competitive muscarinic receptor antagonist that shows in vivo selectivity for the bladder over the salivary glands compared with oxybutinin. Results of randomised double-blind placebo-controlled studies indicate that tolterodine 4 mg/day (administered as immediate-release tablets 2mg twice daily or extended-release capsules 4mg daily) is superior to placebo in improving micturition diary variables in patients with overactive bladder. Moreover, tolterodine 2mg twice daily is as effective as oxybutynin 5mg 3 times daily. Maximum treatment effects with both drugs occurred after 5 to 8 weeks of treatment and improvements were maintained during long term treatment for up to 24 months. In a pooled analysis of four 12-week studies, equivalent and significant reductions in micturition frequency (-2.3 and -2.0 vs -1.4, p < 0.001) and the incidence of urge incontinence episodes (-1.6 and -1.8 vs -1.1, p < 0.05) were reported for tolterodine 2mg twice daily and oxybutynin 5mg 3 times daily compared with placebo. Functional bladder capacity was also significantly increased. Improvements in patient perceptions of their urgency symptoms and of problems caused by their bladder condition were significantly greater during treatment with tolterodine than with placebo. Tolterodine was generally well tolerated in clinical trials of up to 24 months' duration. Dry mouth was the most frequent adverse event. The incidence (40 vs 78%, p < 0.001) and intensity of this event was lower with tolterodine 2mg twice daily than oxybutynin 5mg 3 times daily. Additionally, a 23% lower incidence of dry mouth was reported with once daily extended-release tolterodine capsules than with twice daily immediate-release tablets (p < 0.02). The incidence of adverse CNS events with tolterodine was low and similar to that of placebo. Tolterodine was well tolerated in elderly patients and no serious tolerability concerns were identified.

CONCLUSION

Tolterodine is the first antimuscarinic agent to specifically developed for the treatment of overactive bladder. The functional selectivity of tolterodine for the bladder translates into good efficacy and tolerability in patients, including the elderly, with overactive bladder. Tolterodine is as effective as oxybutynin in improving micturition diary variables but is associated with a significantly lower incidence and intensity of dry mouth. This favourable tolerability profile, together with sustained clinical efficacy during long term treatment, places tolterodine as valuable treatment for the symptoms of overactive bladder.

Evidence for the efficacy and safety of tolterodine in the treatment of overactive bladder

Overactive bladder (OAB) is a chronic and prevalent condition, the symptoms of which (urinary frequency and urgency, with or without urge incontinence) can exert a profound negative effect on a person's daily life activities. Tolterodine (Detrol in North America and Detrusitol in the rest of the world, Pharmacia), a competitive muscarinic antagonist, is the first agent of this class to be specifically developed for the treatment of OAB. This agent displays in vivo functional selectivity for the bladder over other tissues that contain muscarinic receptors (e.g., salivary glands, eye), which translates into good efficacy and tolerability in patients with OAB (including the elderly). Comparative, randomised, double-blind studies show that tolterodine (administered as immediate-release [IR] tablets 2 mg b.i.d.) is as effective as oxybutynin (5 mg t.i.d.) in improving all of the troublesome symptoms of OAB but with a significantly lower incidence and severity of dry mouth. The advent of a new extended-release (ER) capsule formulation of tolterodine (4 mg) for convenient once-daily treatment builds upon these findings, with significantly improved efficacy for reducing urge incontinence episodes and a lower frequency of dry mouth relative to the existing IR tablet (2 mg b.i.d.). Tolterodine can therefore be considered a valuable, well-tolerated treatment option for patients with OAB, providing improvements in symptoms that are both clinically meaningful to patients and sustained during long-term treatment.

Tolterodine reduces the number of urge incontinence episodes in patients with an overactive bladder

OBJECTIVE

To evaluate the efficacy, safety and tolerability of tolterodine compared to placebo in patients with an overactive bladder.

STUDY DESIGN

A double-blind, multi-centre phase III study in France and Belgium 251 patients with overactive bladder symptoms, and urodynamically verified detrusor overactivity, were randomised to receive 4-week treatment with either placebo or tolterodine 1 or 2mg twice daily (bd). Efficacy was evaluated from patient micturition diaries. Safety and tolerability endpoints were also evaluated.

RESULTS

After 4-week treatment, the number of incontinence episodes/24h decreased significantly relative to placebo in the tolterodine 1 and 2 mgbd groups (P=0.045 and P=0.0089, respectively). Both dosages of tolterodine increased volume voided per micturition compared with placebo (P=0.055 and P=0.056, respectively), although significant decreases in micturition frequency were not apparent. Tolterodine was safe and well tolerated, few patients were withdrawn due to adverse events. Dry mouth, mainly of mild-to-moderate intensity, was the most common adverse event. No clinically relevant changes in blood pressure or laboratory safety variables were reported.

CONCLUSION

Tolterodine is effective, safe and well tolerated for the treatment of symptoms of an overactive bladder, particularly urge incontinence.

Tolterodine versus oxybutynin in the treatment of urge urinary incontinence: a meta-analysis

OBJECTIVE

To compare tolterodine with oxybutynin in treatment of urge incontinence.

STUDY DESIGN

A systematic review, following Cochrane methods, was performed to retrieve results of randomized trials that compared tolterodine with oxybutynin in adults with urge incontinence. Composite point estimates of efficacy (episodes of incontinence per 24-hour period, frequency, and voided volume) and safety (dry mouth, withdrawal, and dose modification) were calculated.

RESULTS

Four studies were included. Both drugs similarly decreased the number of micturitions in a 24-hour period. Oxybutynin was marginally superior to tolterodine in decreasing the number of incontinent episodes in a 24-hour period (weighted mean difference, 0.41; 95% confidence interval [CI], 0.04 to 0.77) and increasing the mean voided volume per micturition (8.24 mL; 95% CI, 14.19 to 3.38). Fewer patients had dry mouth (relative risk, 0.54; 95% CI, 0.48 to 0.61) and withdrew from the study because of side effects (relative risk, 0.63; 95% CI, 0.46 to 0.88) with tolterodine.

CONCLUSIONS

Oxybutynin and tolterodine share a clinically similar efficacy profile (although oxybutynin is statistically superior), but tolterodine is better tolerated and leads to fewer withdrawals as a result of adverse events.

Effects of tolterodine, trospium chloride, and oxybutynin on the central nervous system

Antimuscarinic compounds are increasingly used to treat the symptoms of overactive bladder; however, their use is often restricted by peripheral adverse effects (AEs). On the other hand, data regarding their influence on the central nervous system (CNS) are limited. This randomized, single-blind, parallel-group quantitative-topographical EEG (qEEG) study of clinical phase I investigates the potential CNS adverse effects of the three antimuscarinic drugs--tolterodine, oxybutynin, and trospium chloride--in comparison to placebo. Overall, 4 x 16 (total 64) young, healthy male volunteers were included in the study. The subjects were given either placebo or the clinically recommended daily doses of the drugs dispensed in three doses on a single day (tolterodine 2 mg bid and once placebo, total 4 mg/d; oxybutynin 5 mg tid, total 15 mg/d; and trospium chloride 15 mg tid, total 45 mg/d). The qEEG was recorded prior to and up to 4 hours after each intake of the trial medication (a total of 10 qEEG sessions) under three different conditions: at rest with eyes open, eyes closed, and under mental demand. The drug tolerability was subjectively evaluated by the volunteer and the investigator. In comparison to placebo (10% confidence interval), tolterodine and trospium chloride did not induce changes of the qEEG power in five of the six frequency bands (i.e., delta, alpha 1, alpha 2, beta 1, and beta 2). Isolated power decreases were only observed in the theta frequency band. In contrast, oxybutynin caused significant power reductions in four frequency bands (theta, alpha 1, alpha 2, and beta 1; p < 0.01). The subjectively evaluated drug tolerability was comparable between all treatment groups, although differences in the AE occurrence existed, with the AE frequency being higher in the oxybutynin group. The results of this study support the findings that oxybutynin as a tertiary amine crosses the blood-brain barrier, causing significant qEEG activity changes and more pronounced central adverse effects. Although tolterodine is also a tertiary amine, it shows limited effects on qEEG activity (i.e., slight theta power reductions), comparable to the effects of trospium chloride, a quarternary amine, which barely crosses the blood-brain barrier. The minimal qEEG changes observed with tolterodine and trospium chloride reflect most probably a rebound message from the peripheral target organs. Prescription of oxybutynin thus implicates a higher risk of CNS side effects.

Tolterodine once-daily: superior efficacy and tolerability in the treatment of the overactive bladder

OBJECTIVES

To evaluate the efficacy and tolerability of a new extended-release (ER), once-daily, capsule formulation of tolterodine, relative to placebo and the existing immediate-release (IR), twice-daily, tablet formulation, for treatment of the overactive bladder.

METHODS

This was a double-blind, multicenter, randomized, placebo-controlled trial. One thousand five hundred twenty-nine patients (81% women) with urinary frequency (eight or more micturitions every 24 hours) and urge incontinence (five or more episodes per week) were randomized to oral therapy with tolterodine ER 4 mg once daily (n = 507), tolterodine IR 2 mg twice daily (n = 514), or placebo (n = 508) for 12 weeks. Efficacy was assessed at the end of the treatment period on the basis of the micturition diary variables. Tolerability and safety were assessed by evaluating the adverse events, electrocardiogram parameters, laboratory values, and treatment withdrawals.

RESULTS

Tolterodine ER 4 mg once daily (P = 0.0001) and tolterodine IR 2 mg twice daily (P = 0.0005) both significantly reduced the mean number of urge incontinence episodes per week compared with placebo. The median reduction in these episodes as a percentage of the baseline values was 71% for tolterodine ER, 60% for tolterodine IR, and 33% for placebo. The ER formulation was 18% more effective than the IR formulation (P <0.05). Treatment with both formulations of tolterodine was also associated with statistically significant improvements in all other micturition diary variables compared with placebo. For both formulations, the mean decreases in micturition frequency (P <0.0079) and pad usage (P <0.0145) were significant, and the mean volume voided per micturition increased (P = 0.0001). The rate of dry mouth (of any severity) was 23% for tolterodine ER, 30% for tolterodine IR, and 8% for placebo. The overall dry mouth rate for patients taking tolterodine ER was 23% lower than for tolterodine IR (P <0.02), and the rate of severe dry mouth in the ER group was only 1.8%. The rates of withdrawal were comparable for the two active groups and the placebo group. No safety concerns were noted.

CONCLUSIONS

Tolterodine ER 4 mg once daily is effective and well tolerated in the treatment of overactive bladder with no safety concerns. Tolterodine ER demonstrated an improved efficacy for reducing urge incontinence episodes and a lower frequency of dry mouth compared with the existing IR twice-daily formulation.