A Double-blind, Randomised Four-way Crossover Study to Compare the Effects of Fesoterodine 4 and 8 mg Once Daily and Qxybutynin 5 mg Twice Daily After Steady-state Dosing Versus Placebo on Cognitive Function in Overactive Bladder-wet Patients over the Age of 75 Years with Mild Cognitive Impairment

BACKGROUND AND OBJECTIVE

There is a reported association between overactive bladder (OAB) treated with antimuscarinic drugs and an increased risk of a dementia diagnosis, although short-term data suggest that newer OAB antimuscarinics are cognitively safe. This study examined the cognitive safety of fesoterodine in older adults with mild cognitive impairment (MCI) and OAB.

METHODS

This four-way randomised crossover study examined the cognitive effects of fesoterodine 4 and 8 mg and oxybutynin 5 mg b.i.d. compared with placebo. Older adult patients with OAB and MCI were included. Treatment and washout periods were of 1-week duration, to reach steady-state drug levels. The primary outcome was continuity of attention at 1 and 4 h after the dose. The secondary outcomes included other cognitive domains, change in Montreal Cognitive Assessment score, and alertness.

KEY FINDINGS AND LIMITATIONS

Twenty-three patients completed the study (16 females and seven males). For the primary outcome, at 1 h after the dose, a trend towards worsening of continuity of attention was observed for fesoterodine 4 mg (p = 0.09) compared with placebo. At 4 h after the dose, a nonstatistically significant trend towards improvement compared with placebo was observed in the fesoterodine 4 mg group (p = 0.0633) compared with placebo. No differences were observed in any other treatment group at either time point. Apart from quality of working memory, associated with a statistically significant improvement with fesoterodine 4 mg, there was no difference in any comparison for other secondary outcomes.

CONCLUSIONS

Exposure to steady-state dosing of fesoterodine 4 and 8 mg or oxybutynin 5 mg b.i.d. was not associated with any detectable effect on cognitive function using a sensitive battery of cognitive tests in a group of older adult patients with MCI and OAB.

PATIENT SUMMARY

In this report, we investigated whether the medication fesoterodine, a member of a family of drugs called anticholinergics, commonly used for the treatment of a condition called overactive bladder that leads to accidental leakage of urine, affected the memory function of older adults with mild memory impairment. These people might be more sensitive to memory side effects. We found that at the doses most used by doctors, the drug had no effect on any of the memory functions we tested.

Predicting muscarinic receptor occupancy in human bladder mucosa from urinary concentrations of antimuscarinic agents for overactive bladder

To assess the pharmacologically relevant and selective muscarinic receptor occupancy in the bladder mucosa, we considered not only plasma drug concentrations but also urinary drug concentrations. The purpose of this study was to predict muscarinic receptor occupancy in the human bladder mucosa based on urinary concentrations in response to clinical dosages of antimuscarinic agents used to treat overactive bladder. The calculated mean plasma or serum unbound steady state concentrations were 0.06-11 nM in clinical dosages of five antimuscarinic agents. Urinary concentrations calculated from the mean plasma or serum and renal clearance ranged between 19 nM and 2 μM, which were >10-fold higher than the Ki values for bladder muscarinic receptors excluding propiverine. Bladder mucosal muscarinic receptor occupancy estimated from the urinary concentrations and the Ki values was >90 % at a steady state in clinical dosages of five antimuscarinic agents. The bladder muscarinic receptor occupancy was higher than that in the parotid gland calculated based on the mean plasma or serum unbound concentrations and Ki values for muscarinic receptors in the parotid gland. These results suggest that sufficient and selective muscarinic receptor occupancy by antimuscarinic agents, to exert pharmacological effects, in the bladder mucosa can be predicted using urinary concentrations.

On-demand use of fesoterodine: a new paradigm for extended release antimuscarinics

INTRODUCTION AND HYPOTHESIS

We aimed to compare on-demand and continuous use of fesoterodine 4 mg concerning efficacy and adverse effects.

METHODS

A total of 100 patients who were diagnosed with non-neurogenic overactive bladder (OAB) syndrome were included in the study. All patients were evaluated with MMSE, ICIQ-SF, SEAPI quality of health and OAB-V8 questionnaires, at the beginning, 1st month and 4th month. Fesoterodine 4 mg was started for treatment. At the end of the 1st month, patients who obtained benefit from the treatment were 1:1 randomized into two groups. In group 1, fesoterodine 4 mg was given 1 × 1 in a standard manner whereas in group 2 patients took the pills on demand. Both groups were evaluated for efficacy and adverse events at 4 months.

RESULTS

Final analyses included 69 patients. At 4-month follow-up, OAB-V8 scores were significantly improved compared to 1 month in both groups. Again at h months, no difference was detected between the two groups for MMSE, ICIQ-SF and SEAPI scores. In continuous usage group, 4th month MMSE scores were significantly lower than 1st month scores. At 4 months, dry mouth and constipation were lower in the on-demand group compared to continuous usage group.

CONCLUSIONS

Compared to standard continuous usage, on-demand usage of fesoterodine showed similar efficacy with fewer adverse events.

Muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine, and tolterodine in rat tissues after the oral, intravenous, or intravesical administration

The present study aimed to characterize muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine (5-HMT), and tolterodine in bladder and other tissues of rats after their oral, intravenous, or intravesical administration. Muscarinic receptors in tissues were measured by using [N-methyl-³H]scopolamine methyl chloride ([³H]NMS). The in vitro binding affinity for muscarinic receptors was the highest by 5-HMT, followed by tolterodine and fesoterodine. Fesoterodine exhibited lower affinity in rat submaxillary gland than in detrusor muscle and urothelium. Muscarinic binding affinities of 5-HMT and tolterodine were similar among tissues. The duration of binding of oral fesoterodine to muscarinic receptors was longer in bladder than in submaxillary gland, heart, and lung, and its binding was little observed in colon and cerebral cortex. Binding activity of intravenous 5-HMT to muscarinic receptors was significantly observed in all tissues, except cerebral cortex, with a longer duration in bladder. Significant binding of bladder detrusor and urothelial muscarinic receptors was observed following intravesical instillation of 5-HMT. This selectivity may be attributed to the direct blockade of bladder receptors by excreted urinary 5-HMT. Thus, fesoterodine may be efficacious as a treatment for patients with overactive bladder.

[Cost effectiveness of Mirabegron and antimuscarinic drugs in patients with hiperactive bladder.]

OBJECTIVE

To evaluate the costeffectivenessof mirabegron in comparison to theantimuscarinic drugs tolterodine, solifenacin andfesoterodine, in the treatment of urgency, increasedmicturition frequency and urinary incontinence in patientswith overactive bladder (OAB).

MATERIAL AND METHODS

A Markov model in Excel,with a time horizon of 5 years was developed fromthe National Health System and societal perspective.Clinical effectiveness was estimated from a clinical trial(SCORPIO) and a network meta-analysis. Unit costswere obtained from Spanish sources. The effectivenessof the treatments was measured as quality adjusted lifeyears(QALY). Deterministic and probabilistic sensitivityanalyses were performed.

RESULTS

For the 5-year time horizon, the incrementalcost per patient with mirabegron 50 mg versustolterodine was € 195.52 and € 157.42, from theNational Health System (NHS) and societal perspectivesrespectively, with a gain of 0.0127 QALY withmirabegron. Consequently, the cost of gaining a QALYwith mirabegron versus tolterodine was 15,432 € and12,425 € respectively. The probability that mirabegronwould be cost-effective at a willingness to pay thresholdof € 30,000 was: 70% (NHS) and 71% (society)versus tolterodine; 94% (NHS and society) versussolifenacin 5 mg; 84% (NHS) and 84.5% (society)versus solifenacin 10 mg; 96% (NHS and society)versus fesoterodine 4 mg; 98% (NHS) and 99% (society)versus fesoterodine 8 mg. The highest probability thatmirabegron would be cost-effective at a willingness topay threshold of € 20.000 and € 25.000 per QALYgained, is obtained versus fesoterodine 4 mg and 8 mgfrom both NHS and society perspectives.

CONCLUSIONS

The treatment of patients with OABwith mirabegron 50 mg is likely to be cost-effectivecompared to treatment with antimuscarinics.

Fesoterodine: Pharmacological properties and clinical implications

Fesoterodine (as one of three drugs: dutasteride, finasteride and fesoterodine) was classified B (beneficial) by LUTS-FORTA 2014, indicating that it is a medicinal product with proven or obvious efficacy in the elderly, with limited side effects and/or safety concerns. A systematic literature review was undertaken in January 2018 using the PubMed and Google Scholar databases with the following individual and combined keywords: "fesoterodine", "pharmacology", "overactive bladder" and "antimuscarinics". The aim of the review was to determine which of fesoterodine's pharmacological properties explains its clinical benefits in general patient populations with OAB and the elderly in particular. The articles in the results were then selected by publication language (English and French only), methodology (off-topic studies, reported cases and literature reviews were excluded), relevance to the subject matter and publication date prior to 31 January 2018. A total of 205 articles was initially obtained, with 115 read and 45 selected. It appears that the association of four pharmacological properties specific to fesoterodine can explain that this drug has a good balance between efficacy and tolerability. These properties are namely the drug's high and nearly equal affinity for both the M2 and M3 muscarinic receptors, poor penetration of the blood-brain barrier, lack of hepatic first-pass activation -fesoterodine being rapidly and extensively converted to its active metabolite, 5-hydroxymethyl tolterodine, by ubiquitous esterases-, and its extended-release formulation. Fesoterodine's pharmacological profile is optimal for the treatment of overactive bladder. It is now recognized as one of the leading first-line treatment for this indication.

Do patient characteristics predict which patients with overactive bladder benefit from a higher fesoterodine dose?

INTRODUCTION AND HYPOTHESIS

We sought to determine whether baseline characteristics predict which overactive bladder (OAB) patients benefit from fesoterodine 8 mg versus 4 mg.

METHODS

In double-blind, placebo-controlled, flexible-dose trials, baseline characteristics of OAB patients with ≥ 1 urgency urinary incontinence (UUI) episodes/24 h who escalated from fesoterodine 4 mg to 8 mg were evaluated. Possible dose-escalation predictors (age; sex; previous antimuscarinic use; UUI, micturitions, and urgency episodes/24 h; race; body mass index; time to dose escalation; OAB duration) were compared in escalators versus non-escalators. Patients from fixed-dose trials with dose-escalator characteristics were identified (matched dose-escalator sample) to assess changes from baseline with fesoterodine 4 mg, 8 mg, and placebo.

RESULTS

In flexible-dose trials, significant predictors of fesoterodine dose escalation were younger age (≤ 65.8 years), greater number of baseline micturitions (≥ 13.1) and urgency episodes/24 h (≥ 10.9), greater OAB duration (≥ 9.1 years), and more frequent previous antimuscarinic use (58.3%), but not baseline UUI episodes/24 h. In the matched dose-escalator sample (fesoterodine 4 mg: n = 215; 8 mg: n = 198; placebo: n = 217), change from baseline in UUI episodes significantly improved with fesoterodine 8 mg versus 4 mg (P = 0.043) and with both doses versus placebo (P < 0.001). Dry mouth and constipation rates were higher with fesoterodine 8 mg.

CONCLUSIONS

Dose-escalator patients had a significantly greater UUI response with fesoterodine 8 mg versus 4 mg. Given the potential for adverse events, fesoterodine 4 mg is recommended to start; however, patients with UUI and identified predictors may benefit from initial treatment with fesoterodine 8 mg or rapid dose escalation.

Physiological based pharmacokinetic modeling to estimate in vivo Ki of ketoconazole on renal P-gp using human drug-drug interaction study result of fesoterodine and ketoconazole

This study was conducted to estimate in vivo inhibition constant (Ki) of ketoconazole on renal P-glycoprotein (P-gp) using human drug-drug interaction (DDI) study result of fesoterodine and ketoconazole. Fesoterodine is a prodrug which is extensively hydrolyzed by non-specific esterases to the active metabolite 5-hydroxymethyl tolterodine (5-HMT). 5-HMT is then further metabolized via Cytochrome P450 (CYP) 2D6 and CYP3A4. It is reported that 5-HMT is a substrate of P-gp whereas fesoterodine is not. Renal clearance of 5-HMT is approximately two-times greater than renal glomerular filtration rate. This suggests the possibility that renal clearance of 5-HMT involves secretion by P-gp. Utilizing the available pharmacokinetic characteristics of fesoterodine and 5-HMT, we estimated in vivo Ki of ketoconazole on P-gp at kidney based on DDI study data using physiologically-based pharmacokinetic approach. The estimated in vivo Ki of ketoconazole for hepatic CYP3A4 (6.64 ng/mL) was consistent with the reported values. The in vivo Ki of ketoconazole for renal P-gp was successfully estimated as 2.27 ng/mL, which was notably lower than reported in vitro 50% inhibitory concentration (IC₅₀) values ranged 223-2440 ng/mL due to different condition between in vitro and in vivo.

Cost effectiveness analysis of fesoterodine compared to mirabegron in first-line therapy setting for overactive bladder with urge urinary incontinence, from the Spanish National Health System perspective

OBJECTIVES

To evaluate the cost-effectiveness of first-line treatment of Overactive Bladder (OAB) with fesoterodine relative to mirabegron, from the Spanish National Health System (NHS) perspective.

METHODS

A decision tree model was developed to represent a typical clinical process of 52-week of treatment for an OAB patient with urge urinary incontinence (UUI) initiating first-line therapy with fesoterodine 4mg, including optional titration to 8mg, vs.mirabegron 50mg. Efficacy data were obtained from a Bayesian indirect treatment meta-analysis. Patients with UUI of less than one episode/day were defined as treatment responder and persistence was assessed at weeks 4, 12 and 24. At week 12, non-responders discontinued treatment permanently. Quality-adjusted life years (QALYs) were calculated based on time spent in responder and non-responder states. OAB-related drug and medical care costs including physician visits, laboratory tests, incontinence pads, and comorbidities (fracture, skin infection, urinary tract infections and depression) were modeled and expressed in €2015.

RESULTS

At week 52, the percentage of responders was 20.8% for patients starting on fesoterodine 4mg who optionally titrated to 8mg and 19.4% for patients treated with mirabegron. QALYs were slightly higher with fesoterodine than mirabegron (0.7703vs. 0.7668, difference=0.0035). Fesoterodine treatment also had slightly higher total costs than mirabegron (3,296€vs. 3,217, difference=79€), resulting in a cost of 22,523/QALY€ gained for fesoterodine versus mirabegron. Probabilistic sensitivity analysis confirmed the slight advantage of fesoterodine with a 61.1% probability of being cost-effective at the 30,000€ willingness-to-pay for 1QALY threshold.

CONCLUSIONS

Given the relatively small 1-year cost difference between the two treatments, fesoterodine can be considered a cost-effective option relative to mirabegron for the first-line management of OAB with UUI in Spain.

Development of a predictive model for urgency urinary incontinence

The ability to set realistic expectations of treatment response in patients with overactive bladder (OAB) can have an impact on patient engagement and adherence to study medication. In order to help set treatment expectations for OAB, a Physician Predictive Tool has been developed based on predictive modelling. Models have been developed utilizing data from eight Phase 3 and 4 fesoterodine clinical trials and these models enable the prediction of individual treatment response in subjects with OAB, based on various baseline characteristics. The data utilized and covariates that were hypothesized to influence treatment response are described. The model selection and development process are also outlined, and the final model and some example results utilizing this model are presented. Finally, we discuss the potential benefits and limitations of such a predictive tool.

Safety and efficacy of fesoterodine fumarate in patients with overactive bladder: results of a post-marketing surveillance study in Korea

OBJECTIVES

The aim of this study was to evaluate the safety and efficacy of fesoterodine fumarate (fesoterodine; Toviaz ) in Korean patients with overactive bladder (OAB) in routine clinical practice.

METHODS

This was an open-label, non-interventional, prospective, post-marketing surveillance study submitted to the Korean Ministry of Food and Drug Safety. A total of 3109 patients aged ≥18 years with OAB symptoms were prescribed flexible doses of fesoterodine at the investigator's discretion. Safety was assessed based upon the reporting of adverse events (AEs). Efficacy was evaluated on the basis of patient self-assessment using a bladder diary as well as on the basis of investigator assessment in terms of overall clinical efficacy.

RESULTS

A final analysis was performed on 3107 (99.9%) and 2978 (95.8%) patients for safety and efficacy analysis, respectively. The mean treatment duration of fesoterodine was 83.2 days. The incidence of AEs was 8.5% (265/3107). Common AEs that accounted for more than 1.0% of the total AE incidence included dry mouth (5.4%, 168/3107), constipation (1.5%, 48/3107) and micturition disorder (1.1%, 35/3107). Mean episodes of urinary frequency, urgency, and urgency urinary incontinence (UUI) per 24 hours decreased by 4.0, 2.4, and 0.8, respectively (all p < 0.001). At the final follow-up visit, the investigators found improvement in clinical efficacy for the majority of patients (90.1%, 2684/2978). Limitations of this study include the observational study design and the relatively short treatment duration.

CONCLUSION

These results suggest that fesoterodine is a well tolerated and effective treatment for Korean patients with OAB in routine clinical practice.

Economic impact of using fesoterodine for the treatment of overactive bladder with urge urinary incontinence in a vulnerable elderly population in the United States

OBJECTIVES

To assess the costs of treating overactive bladder (OAB) with fesoterodine compared to no OAB pharmacotherapy among vulnerable elderly from the US payer perspective.

METHODS

A decision analytic cost model was developed to estimate the 52-week costs of a cohort of vulnerable elderly with OAB initiating treatment with fesoterodine or no OAB pharmacotherapy. Vulnerable elderly OAB patients were defined as those aged ≥65 years with self-reported urge urinary incontinence (UUI) symptoms for ≥3 months, 2-15 UUI episodes/day, and at risk of deteriorating health by a score of ≥3 on the Vulnerable Elders Survey (VES)-13. Patients were evaluated for fesoterodine treatment response (defined as no UUI episodes) and persistence at weeks 12, 26, and 52. The model included a hypothetical health plan with 100,000 elderly members. A total of 7096 vulnerable elderly subjects were identified as the model target population based on the percentage of vulnerable elderly and annual prevalence of OAB among vulnerable elderly. OAB-related costs included fesoterodine drug acquisition costs, healthcare resource use (inpatient hospitalization, outpatient visits, and physician office visits), and OAB-related co-morbidities (falls/fractures, urinary tract infections, depression, and nursing home admissions). All costs were inflated to 2013 US$ using the medical care component of the consumer price index (CPI).

RESULTS

When 7096 vulnerable elderly OAB patients were treated with fesoterodine, US healthcare payers could save $11,463,981 per year, or $1616 per patient vs no OAB pharmacotherapy. Univariate one-way sensitivity analyses supported the robustness of the findings and showed results were most sensitive to changes in fesoterodine efficacy followed by annual costs of inpatient hospitalization.

CONCLUSIONS

From a US payer perspective, treating vulnerable elderly OAB patients with fesoterodine was cost-saving compared to no OAB pharmacotherapy.

Fesoterodine clinical efficacy and safety for the treatment of overactive bladder in relation to patient profiles: a systematic review

OBJECTIVE

To summarize published evidence on the pharmacology, efficacy, and safety of fesoterodine for the treatment of overactive bladder (OAB) symptoms in relation to patient clinical and demographic profiles.

METHODS

A systematic review of published articles on fesoterodine was conducted via a PubMed search. Articles were identified using the search term fesoterodine, with limits of human species and abstract available. Review and meta-analysis articles, validation studies, articles focused on treatment compliance/adherence, meeting abstracts, and articles not focused on oral fesoterodine administration in human subjects were excluded. Data from retained articles were summarized descriptively.

RESULTS

Of 137 articles identified, 61 (15 articles on the pharmacology and 46 articles on the efficacy and/or safety of fesoterodine) met inclusion criteria. Superiority trials demonstrated the additional efficacy of fesoterodine 8 mg versus fesoterodine 4 mg and tolterodine extended release 4 mg in treating OAB. Prospective trials in specific patient populations indicated beneficial effects of fesoterodine in elderly patients, vulnerable elderly patients, patients dissatisfied with or with a suboptimal response to previous antimuscarinic therapy, patients with urge urinary incontinence (UUI) or nocturnal urgency, and men with persistent LUTS during alpha-blocker treatment. With two effective doses, the fesoterodine dose can be adjusted to achieve optimal efficacy and tolerability in individual patients. The most common adverse events during fesoterodine treatment are dry mouth and constipation.

CONCLUSIONS

Extensive evidence demonstrates the efficacy and safety of fesoterodine in relieving OAB symptoms, including urgency, urinary frequency, UUI, and nocturnal urgency, in patients with various clinical and demographic profiles. Trial results provide valuable information on fesoterodine treatment in specific patient populations, including both elderly and vulnerable elderly patients. Potential limitations of this review are that only English language articles in PubMed were searched and included.

Adherence to fesoterodine in women with overactive bladder in routine clinical practice

OBJECTIVES

To assess the short-term compliance with fesoterodine treatment and to identify the reasons for lack of adherence and discontinuation in routine clinical practice. The secondary aim was to estimate the patient-reported outcomes.

METHODS

This was an observational retrospective, multicenter study conducted in a sample of women with overactive bladder on fesoterodine treatment for at least three months. Adherence to medication was assessed using the Morisky-Green test. Patient-reported outcomes were assessed using the Incontinence Questionnaire Short Form (ICIQ-SF), Overactive Bladder Questionnaire Short Form (OAB-qSF), and Treatment Benefit Scale (TBS).

RESULTS

One hundred and twenty women with a mean age [standard deviation (SD)] of 62.2 (12.0) years with severe OAB [mean (SD) ICIQ-SF score 13.2 (4.0)] were included. 42.1% of the patients were considered compliant with fesoterodine treatment. The main causes for non-compliance/discontinuation stated by the remaining 57.9% of the patients were adverse events (62.2%) and lack of clinical benefits (20.0%). The illness status as well as the patient-perceived bother occasioned by the OAB symptoms and their impact on the quality of life improved significantly after three months on fesoterodine treatment (p<0.0001). Most of the patients stated that the current state of their urinary problems had greatly improved/ improved.

CONCLUSION

In routine clinical practice, a high percentage of patients were adherent to fesoterodine and perceived the benefit that the treatment provided them three months after starting treatment. However, more than half of the study population failed to comply or discontinued the treatment mainly due to intolerance or lack of efficacy.

Monolithic LC method applied to fesoterodine fumarate low dose extended-release tablets: Dissolution and release kinetics

A dissolution test for fesoterodine low dose extended-release tablets using liquid chromatographic (LC) method equipped with a C₁₈ monolithic column was developed and validated. LC system was operated isocratically at controlled temperature (40 °C) using a mobile phase of acetonitrile:methanol:0.03 M ammonium acetate (pH 3.8) (30:15:55, v/v/v), run at a flow rate of 1.5 mL/min and detected at 208 nm. The best dissolution conditions for this formulation were achieved using a USP apparatus 2 (paddle) at 100 rpm and 900 mL of phosphate buffer at pH 6.8 as the dissolution medium. Validation parameters such as the specificity, linearity, accuracy, precision, and robustness were evaluated according to international guidelines, giving results within the acceptable range. The kinetic parameters of drug release were also investigated using model-dependent methods and the dissolution profiles were best described by the Higuchi model. The validated dissolution test can be applied for quality control of this formulation.

Therapeutic benefit in patients switching tolterodine to other novel antimuscarinic agents

OBJECTIVES

To explore in the daily clinical practice setting that antimuscarinic, Fesoterodine or Solifenacin, provides a greater clinical benefit after changing their prior Overactive Bladder (OAB) therapy with tolterodine extended-release (ER) to other novel antimuscarinic agents.

MATERIAL AND METHODS

A post-hoc analysis of data from an observational multicenter, cross-sectional, retrospective study. Adult patients of both sexes, with OAB and OAB-V8 score≥8, who switched to fesoterodine or solifenacin within the 3-4 months before study visit from their prior tolterodine-ER-based therapy due to poor response were included. 92 patients were selected for each treatment group, matched (1:1) according to conditioned probability using the propensity score. Benefit of treatment change perceived by the physician and patient was evaluated by means of the Clinical Global Impression of Improvement subscale (CGI-I) and Treatment Benefit Scale (TBS), respectively. Degree of worry, bother and interference with daily living activities due to urinary symptoms, level of satisfaction, and preference for current treatment were also assessed.

RESULTS

Fesoterodine provided a significantly greater improvement than solifenacina in terms of therapeutic benefit perceived by the physician according to ICG-I. 96.7% of the patients on fesoterodine treatment vs. 81.6% of the solifenacin group showed a score of improvement in TBS (P<.05). Fesoterodine was also better rated than solifenacin with regard to satisfaction and preference for the new treatment (93.4 vs. 78.2% P<.05).

CONCLUSIONS

In daily clinical practice the switch from tolterodine LP to fesoterodine seems to provide greater benefits both from the physician's and the patient's point of view compared with those provided by solifenacin.

Chronic administration of anticholinergics in rats induces a shift from muscarinic to purinergic transmission in the bladder wall

BACKGROUND

First-line pharmacotherapy for overactive bladder consists of anticholinergics. However, patient compliance is exceptionally low, which may be due to progressive loss of effectiveness.

OBJECTIVE

To decipher the involved molecular mechanisms and to evaluate the effects of chronic systemic administration of anticholinergics on bladder function and on muscarinic and purinergic receptors expression in rats.

DESIGN, SETTING, AND PARTICIPANTS

Female Wistar rats were implanted with an osmotic pump that chronically administered vehicle (Vehc), 0.36 mg/kg per day oxybutynin (Oxyc), or 0.19 mg/kg per day fesoterodine (Fesoc) for 28 d.

INTERVENTIONS

For cystometry experiments, a small catheter was implanted in the bladder.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Urologic phenotype was evaluated by the analysis of the micturition pattern and urodynamics. Expression of muscarinic and purinergic receptors was assessed by Western blot analysis of detrusor membrane protein. Functional responses to carbachol and adenosine triphosphate (ATP) were evaluated using muscle-strip contractility experiments.

RESULTS AND LIMITATIONS

The number of voided spots was transiently decreased in Oxyc rats. In Oxyc rats, the effect of an acute high dose of oxybutynin (1mg/kg intraperitoneally [IP]) on the intermicturition interval was abolished. Expression experiments revealed a decrease of muscarinic acetylcholine receptors M2 (mAChR2) and M3 (mAChR3), whereas the purinergic receptor P2X, ligand-gated ion channel, 1 (P2X1) was enhanced in Oxyc and Fesoc rats compared to Vehc rats. In concordance with the modification of the expression pattern in Oxyc rats, the force generated by carbachol and ATP in muscle-strip contractility experiments was, respectively, lower and higher. Urodynamics revealed that the effects of systemic administration of the purinergic blocker pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (50mg/kg IP) were enhanced in Oxyc rats. As rat bladder physiology is different from that of humans, it is difficult to directly extrapolate our findings to human patients.

CONCLUSIONS

Chronic administration of anticholinergics in rats induces receptor loss of efficiency and a shift from muscarinic to purinergic transmission.