Efficacy, according to urodynamics, of OnabotulinumtoxinA compared with antimuscarinic drugs, for neurogenic detrusor overactivity: a systematic review and network meta-analysis.

To summarize the differences in urodynamic outcomes between oral antimuscarinic drugs and OnabotulinumtoxinA, and finding a therapy that maintains good urodynamics in neurogenic detrusor overactivity (NDO). We conducted a literature search of EMBASE and PubMed, with the language limited to English. In the analysis, all of the published randomized trials of OnabotulinumtoxinA or antimuscarinic drugs used to treat NDO were found and the results were finally obtained through Bayesian model analysis. A total of 12 RCTs and 2208 patients were included. OnabotulinumtoxinA 300U was superior to other drugs in terms of MCC, volume at IDC, and Pdetmax endpoints. OnabotulinumtoxinA 200U was more effective on the urodynamic endpoint of BC than other drugs or doses of OnabotulinumtoxinA. According to the MCC urodynamic results, oxybutynin, solifenacin 10 mg, and tolterodine 4 mg also had positive effects. OnabotulinumtoxinA 300U, 200U and 100U were better in improving the urodynamic results of NDO, and the current evidence also shows that selective injection of onabotulinumtoxinA can effectively improve the urodynamic results.

Molecular Determinants for the High-Affinity Blockade of Human Ether-à-go-go-Related Gene K + Channel by Tolterodine.

ABSTRACT: Tolterodine is a first-line antimuscarinic drug used to treat overactive bladder. Adverse cardiac effects including tachycardia and palpitations have been observed, presumably because of its inhibition of the human ether-à-go-go-related gene (hERG) K + channel. However, the molecular mechanism of hERG channel inhibition by tolterodine is largely unclear. In this study, we performed molecular docking to identify potential binding sites of tolterodine in hERG channel, and two-microelectrode voltage-clamp to record the currents of hERG and its mutants expressed in Xenopus oocytes. The results of computational modeling demonstrated that phenylalanine at position 656 (F656) and tyrosine at position 652 (Y652) on the S6 helix of hERG channel are the most favorable binding residues of tolterodine, which was validated by electrophysiological recordings on Y652A and F656A hERG mutants. The Y652A and F656A mutations decreased inhibitory potency of tolterodine 345-fold and 126-fold, respectively. The Y652A mutation significantly altered the voltage dependence of channel inhibition by tolterodine. For both the wild-type and the mutant channels, tolterodine reduced the currents in a time-dependent manner, and the blockade occurred with the channel activated. Tolterodine did not interfere with hERG channel deactivation, whereas channel inactivation greatly impaired its blocking effect. The inhibition of hERG channel by tolterodine is independent of its action on muscarinic acetylcholine receptors. In conclusion, tolterodine is an open-state blocker of hERG K + channel with nanomolar potency. Y652 and F656, 2 aromatic residues on the inner S6 helix, are responsible for the high-affinity binding of tolterodine to hERG channel.

Different interventions for preventing postoperative catheter-related bladder discomfort: a systematic review and meta-analysis.

OBJECTIVE: Catheter-related bladder discomfort (CRBD) is a common complication of intraoperative urinary catheterization. Various studies have evaluated the efficacy of different interventions in postoperative CRBD. The present review was performed to assess the efficacy of these interventions. METHODS: PubMed, Embase, and CENTRAL (Cochrane Central Register of Controlled Trials) databases were systematically searched to identify randomized controlled trials (RCTs) investigating the efficacy of different drugs for the prevention of postoperative CRBD. This review evaluated the incidence and severity of CRBD after different interventions at 0, 1, 2, and 6 h postoperatively. RESULTS: Forty-five studies including 31 different drugs were analyzed. Eleven drugs were investigated in more than two RCTs, of which dexmedetomidine, gabapentin, tolterodine, tramadol, ketamine, nefopam, oxybutynin, pregabalin, and pudendal nerve block (PNB) generally showed significantly higher efficacy than controls postoperatively. Solifenacin only showed significant efficacy compared with the control at 0 h, and intravenous lidocaine only showed significant efficacy compared with the control at 6 h. There were insufficient trials to draw conclusions regarding atropine, butylscopolamine, chlorpheniramine, clonidine, darifenacin, diphenhydramine, glycopyrrolate, intravesical bupivacaine, ketamine-haloperidol, pethidine-haloperidol, ketorolac, lidocaine-prilocaine cream, magnesium, hyoscine n-butyl bromide, oxycodone, paracetamol, parecoxib, trospium, resiniferatoxin, or amikacin. However, all but pethidine-haloperidol and chlorpheniramine showed some efficacy at various time points compared with controls. CONCLUSION: This review suggests that dexmedetomidine, gabapentin, tolterodine, tramadol, ketamine, nefopam, oxybutynin, pregabalin, and PNB are effective in preventing postoperative CRBD. Considering the efficacy and adverse effects of all drugs, dexmedetomidine and gabapentin were ranked best.

Efficacy of the combination of KPR-5714, a novel transient receptor potential melastatin 8 (TRPM8) antagonist, and ß3-adrenoceptor agonist or anticholinergic agent on bladder dysfunction in rats with bladder overactivity.

Transient receptor potential melastatin 8 (TRPM8) channels may contribute to the pathophysiological bladder afferent hyperactivity, thus a TRPM8 antagonist would be a promising therapeutic target for the bladder hypersensitive disorders including urinary urgency in overactive bladder (OAB). We aimed to investigate a pharmacological effect of KPR-5714, a novel selective TRPM8 antagonist, on TRPM8 channels, M3 receptors and ß3-adrenoceptors using the transfected cells of each gene at first. Then, combination effects of KPR-5714 and mirabegron, a ß3-adrenoceptor agonist, or tolterodine tartrate, an anticholinergic agent, were studied on rhythmic bladder contractions (RBCs) in normal rats and bladder function in frequent-voiding rats. In vitro measurements showed that KPR-5714 acts on neither ß3-adrenoceptor nor M3 receptor. In normal rats, KPR-5714 and mirabegron significantly reduced the frequency of RBCs, and a combined administration showed an additive effect. In rats with cerebral infarction, KPR-5714 and mirabegron significantly reduced the voiding frequency, and a combined administration showed an additive effect. In rats exposed to cold temperature, KPR-5714 and tolterodine tartrate significantly reduced the voiding frequency accompanied by the increased mean voided volume, and a combined administration showed additive effects. The present study demonstrated that the combined administration of KPR-5714 and mirabegron or tolterodine tartrate showed the additive effects on bladder dysfunction in different animal models, suggesting that the combination therapy of TRPM8 antagonist and ß3-adrenoceptor agonist or anticholinergic agent can be the potential treatment option for obtaining additive effects in comparison with monotherapy for OAB.

Effect of Antimuscarinic Drugs on Cognitive Functions in the Management of Overactive Bladder in Elderly.

BACKGROUND: overactive bladder (OAB) affects 17-41% older adults in community dwelled setting. For several years, antimuscarinics have been validated as the first-line medical treatment for OAB. Despite abundant data obtained from clinical trials provisions the use of antimuscarinics, investigation about the effect of this drug on cognitive function in elderly remains scarce. The objective of this study is to investigate the effect of antimuscarinics therapy on cognitive functions in OAB geriatric patients. METHODS: this study design is a systematic review and meta-analysis. Studies were collected using several search engines; those were PubMed, Science Direct, Cochrane, and EBSCOhost using predetermined MeSH keywords with Boolean operators. Selection of studies was done by three reviewers. Studies which fulfilled the inclusion and exclusion criteria underwent full-text review. For every selected full text, we extracted the following data if available: patients demographics, types of antimuscarinics used, placebo, dose, follow-up period, and Mini-Mental State Examination (MMSE) total score. RESULTS: a total of 8 studies from an initial 146 publications were selected. There were 8 antimuscarinic agents evaluated in the studies, including Oxybutynin, Darifenacin, Tolterodine, Trospium, Imidafenacin, Propiverine hydrochloride, Fesoterodine, and Solifenacin. Oxybutynin was shown to have largest effect towards the decline of MMSE score [Mean difference: -2.90; 95% CI: -4.07, -1.73]. Darifenacin and Tolterodine were also shown to be significant in the decline of total MMSE score, although still inferior to Oxybutynin. CONCLUSION: the use of most antimuscarinics medication has little to no effect towards the cognitive function in the management of overactive bladder in elderly patients. However, Oxybutynin, Darifenacin, and Tolterodine was shown to have significant decrease in cognitive functions, as shown in the decline of total MMSE score.

Comparison of vascularization and overall perfusion of the bladder wall between women with and without overactive bladder syndrome.

The pathophysiology of female overactive bleeder syndrome (OAB) remains undetermined. Our aim is to elucidate the role of vacularization and overall perfusion of the bladder wall in women with OAB. Between 2010 and 2016, women with OAB and the asymptomatic controls were enrolled. Women with OAB were treated with tolterodine. Women with OAB (n = 40) had higher vascularization index (0.40 ± 0.57 versus 0.17 ± 0.22, p = 0.003), vascularization-flow index (0.15 ± 0.28 versus 0.05 ± 0.08, p = 0.003) and thicker trigone (0.56 ± 0.13 cm versus 0.47 ± 0.11 cm, p = 0.004), compared with the controls (n = 34). The following optimum cut-off values to predict OAB were determined: (1) vascularization index (%) ≥ 0.16, (2) vascularization-flow index ≥ 0.032, and (3) trigone bladder wall thickness ≥ 0.47 cm with an area under the curve of 0.71, 0.71 and 0.70, respectively. Correlation analysis showed that a significant correlation between urgency and vascularization index/vascularization-flow index (Spearman's rho = 0.34 and 0.35, respectively, all p < 0.01). However, after 12 weeks of tolterodine treatment, the vascularization index, flow index and vascularization-flow index did not differ between baseline and after treatment. In conclusion, women with OAB have higher vascularization and overall perfusion of the bladder wall, compared women without OAB. However, vascularization and overall perfusion did not change after antimuscarinic treatment.

Combination drug therapy against OAB normalizes micturition parameters and increases the release of nitric oxide during chemically induced cystitis.

Today, monotherapy is the most common pharmacological treatment option for patients suffering from overactive bladder (OAB). Recent reports have indicated potential benefits of combination therapy, using a muscarinic antagonist and a ß3 -adrenoceptor agonist. This may be of particular interest for therapy-resistant patients with OAB and concomitant cystitis. The objective of the current study was to assess how combination therapy affects bladder parameters in health and cystitis and if the efficacy of the drugs can be linked to altered release of nitric oxide (NO). Rats were pretreated with either a combination of the muscarinic antagonist tolterodine and ß3 -selective adrenoceptor agonist mirabegron or saline for 10 days. Forty-eight hours prior to assessing micturition parameters in a metabolic cage, the rats were intraperitoneally injected with cyclophosphamide, causing cystitis, or saline. Urine samples were collected and analyzed for NO content. Bladder contractile properties were assessed in an organ bath setup. Induction of cystitis led to bladder overactivity. Combination therapy normalized bladder parameters. Both induction of cystitis and drug treatment increased the release of NO. The innate contractile properties of the bladder were unaffected by combination therapy. This study demonstrates positive effects of combination drug therapy on symptoms of OAB, possibly indicating it to be a good option for treatment of OAB during concomitant cystitis. It remains to be determined if increased release of NO is crucial for successful pharmacological treatment of bladder overactivity during cystitis.

Muscarinic receptors promote pacemaker fate at the expense of secondary conduction system tissue in zebrafish.

Deterioration or inborn malformations of the cardiac conduction system (CCS) interfere with proper impulse propagation in the heart and may lead to sudden cardiac death or heart failure. Patients afflicted with arrhythmia depend on antiarrhythmic medication or invasive therapy, such as pacemaker implantation. An ideal way to treat these patients would be CCS tissue restoration. This, however, requires precise knowledge regarding the molecular mechanisms underlying CCS development. Here, we aimed to identify regulators of CCS development. We performed a compound screen in zebrafish embryos and identified tolterodine, a muscarinic receptor antagonist, as a modifier of CCS development. Tolterodine provoked a lower heart rate, pericardiac edema, and arrhythmia. Blockade of muscarinic M3, but not M2, receptors induced transcriptional changes leading to amplification of sinoatrial cells and loss of atrioventricular identity. Transcriptome data from an engineered human heart muscle model provided additional evidence for the contribution of muscarinic M3 receptors during cardiac progenitor specification and differentiation. Taken together, we found that muscarinic M3 receptors control the CCS already before the heart becomes innervated. Our data indicate that muscarinic receptors maintain a delicate balance between the developing sinoatrial node and the atrioventricular canal, which is probably required to prevent the development of arrhythmia.

Which antimuscarinic agents used in the treatment of overactive bladder increase heart rate? a prospective randomized clinical trial.

PURPOSE: To compare the heart rate increase side effect of different antimuscarinic drugs used in overactive bladder (OAB). METHODS: Overall 341 patients were consecutively randomized to take seven different antimuscarinic drugs between January 2014 and June 2016 at three institutions, and 250 patients who completed the follow-up visits were accepted into this study. Ninety-one patients who never came to visits were excluded. Drugs were classified into two groups as selective (darifenacin hydrobromide, solifenacin succinate and oxybutynin hydrochloride) and non-selective (fesoterodine fumarate, tolterodine tartrate, trospium chloride and propiverine hydrochloride) antimuscarinic drugs. The cardiac pulse rates and the blood pressures were recorded during the baseline, first visit (1 week) and second visit (1 month). Data were compared for drugs and two groups (selective versus non-selective) by using ANOVA test. RESULTS: Baseline characteristics were similar among the patients using different antimuscarinic drugs. Statistically significant increase in heart rate occurred in patients treated with non-selective antimuscarinic drugs compared to those treated with selective drugs (p < 0.001), and this increase was especially evident in patients treated with trospium chloride, tolterodine tartrate, fesoterodine fumarate and propiverine hydrochloride (p < 0.001, 0.003, 0.011 and 0.37, respectively). There was no statistical difference for the other side effects. CONCLUSIONS: Our results showed that heart rate significantly increased in OAB patients treated with non-selective antimuscarinic drugs. Trospium chloride, tolterodine tartrate, fesoterodine fumarate and propiverine hydrochloride seem to have the most unfavorable properties with regard to increased heart rate side effect when compared to the other antimuscarinic drugs (darifenacin hydrobromide, solifenacin succinate and oxybutynin hydrochloride).

The Antimuscarinic Agent Tolterodine Regulates Bladder Extracellular Matrix in Partial Bladder Outlet Obstruction in Rats.

BACKGROUND/AIMS: Antimuscarinic agents can delay the progression of bladder dysfunction caused by bladder outlet obstruction (BOO). To date, the relationship between muscarinic receptor activity and the bladder extracellular matrix (ECM) remains unclear. Thus, an animal model of partial BOO (PBOO) in female rats was established to explore the variation in bladder wall ECM proteins under PBOO conditions with antimuscarinic agent administration. METHODS: Rats were randomly divided into three groups: sham, PBOO, and PBOO plus tolterodine. Picrosirius red staining was used to examine the smooth muscle and collagen content of bladder samples. Gene microarray and RT-PCR were performed to survey the expression of ECM proteins, receptors, and metabolism regulators in the rat bladder. Positive results were further evaluated by immunohistochemistry. RESULTS: Picrosirius red staining showed that smooth muscle volume significantly increased in the PBOO and PBOO plus tolterodine groups (p < 0.05), while collagen significantly increased in the PBOO group (p < 0.05) but not in the PBOO plus tolterodine group. Gene microarray and RT-PCR revealed that none of the collagen subtypes exhibited significant changes after PBOO establishment and tolterodine administration. However, matrix metalloproteinases (MMPs) increased significantly in the PBOO plus tolterodine group (p < 0.05). Additionally, PBOO inhibited the expression of non-collagen ECM proteins in the rat bladder wall, while tolterodine induced the expression of non-collagen ECM proteins and ECM receptors. CONCLUSIONS: Tolterodine decreased the volume of collagen in PBOO rat bladder wall, possibly via MMPs, and regulated the expression of ECM proteins and receptors.

Comparisons of the Clinical Outcomes and Urodynamic Effects of Mirabegron versus Tolterodine Treatment for Female Overactive Bladder Syndrome: A Subgroup Analysis of a Controlled, Randomised, Prospective Study.

OBJECTIVES: The impact of mirabegron on clinical outcome and urodynamic parameters may be important for clinical practice. Thus, the aim of this study was to compare the clinical outcomes and urodynamic effects of mirabegron (Betmiga 50 mg) versus tolterodine (Detrusitol ER 4 mg) treatment for women with overactive bladder syndrome (OAB). METHODS: Women with OAB were randomized to receive 12 weeks of mirabegron 50 mg, tolterodine extended-release 4 mg or placebo treatment. The clinical outcomes and urodynamic effects were compared between the subgroups. RESULTS: Thirty-three women completed 12 weeks of mirabegron (n = 12), tolterodine (n = 12) or placebo (n = 9) treatment. A significant increase in the volumes at strong desire to void and a decrease in the daytime frequency episodes were identified in the mirabegron and tolterodine groups (all P < 0.05). Nonetheless, a decrease in the total voided volume was identified following mirabegron treatment but not tolterodine (P = 0.02). CONCLUSIONS: Mirabegron and tolterodine exhibit similar changes in the urodynamics and bladder diary parameters. However, mirabegron may decrease the total voided volume. These findings may serve as an initial guide or assist in consultations regarding the treatment of OAB patients with mirabegron.

Inhibition of salivary secretion by tolterodine transdermal patch.

Tolterodine, a nonselective muscarinic antagonist available only as immediate release (IR) or extended release (ER) oral formulations, is used for the treatment of overactive bladder (OAB). This study aimed to compare the efficacy and extent of dry mouth adverse effects of tolterodine transdermal patch to the oral formulation. The two formulations have been examined through the muscarinic receptor binding tests conducted in bladder and salivary gland tissues and the salivary secretion tests conducted in rats. Comparable average tolterodine blood concentration levels were obtained 3 h after oral administration of tolterodine 25 mg/kg and 12 h after transdermal application of tolterodine patch 6 mg/8 cm2. While Kd in the bladder tissue increased to a similar degree in both formulations of tolterodine, Kd in the salivary gland increased to a greater degree in the oral formulation. These results indicate that similar degree of inhibitory effects were observed in the bladder for both formulations while less inhibitory effects were observed in the salivary gland with tolterodine transdermal formulation compared to the oral formulation. For assessment of salivary secretion, tolterodine transdermal patch 6 mg/8 cm2 application resulted in significantly less inhibitory effects than oral tolterodine 25 mg/kg. Therefore, this study suggests that tolterodine transdermal patch could be a useful formulation that provides uniform and consistent inhibitory effects to effectively control OAB symptoms with reduced severity of dry mouth in comparison to the oral formulation.

Protective Effects of Antimuscarinics on the Bladder Remodeling After Bladder Outlet Obstruction.

BACKGROUND/AIMS: Overactive bladder associated with bladder outlet obstruction (BOO) is a highly prevalent condition, which is usually treated with antimuscarinics. However, the potential effects of antimuscarinics on the structure and function of bladder have not been investigated thus far. METHODS: Sprague-Dawley(R) rats accepted bladder neck obstruction surgery or sham surgery, and then received treatment of three different antimuscarinics (Solifenacin, Darifenacin, and Tolterodine) or vehicle. After 3, 6 and 12 weeks, the bladder function and structure were measured. The effect of antimuscarinics on cellular alteration in vitro was observed under mechanical stimulation. Bladder morphology were examined by immunohistochemistry, and the bladder function were investigated by cystometry and strip contractility test. The expression of muscarinic receptors and inflammatory cytokines were measured by PCR and Western blotting. RESULTS: Here we demonstrate, both in vitro and in vivo, that antimuscarinics are protective regulators for the bladder structure and function. Antimuscarinics decrease the weight of bladders with BOO. Antimuscarinics improve the voiding parameter and enhance the contraction of bladder smooth muscle. The results also show that antimuscarinics inhibit the proliferation of bladder smooth muscle cells both in vivo and in vitro, it can reduce the collagen deposition and inflammatory cytokines in bladders with BOO. During this process, the expression of M2 and M3 receptors was altered by antimuscarinics. CONCLUSION: Antimuscarinics could reverse the structural and functional changes of BOO bladder wall at cellular and tissue level, and the alteration of M2 and M3 receptors may be involved in this biological process.

Tolterodine treatment of women with overactive bladder syndrome: Comparison of night-time and daytime dosing for nocturia.

AIM: We aimed to clarify the impact of night-time dosing with tolterodine extended release (ER) on nocturia. METHODS: The bladder diaries, urodynamic studies, and medical records of female patients with overactive bladder syndrome who were diagnosed between January 2005 and December 2015, and treated with tolterodine ER 4 mg once per day (night-time or daytime dosing) for 12 weeks in the urogynecology outpatient clinics of two tertiary referral centers were reviewed retrospectively. RESULTS: A total of 72 female patients were reviewed. Thirty-six patients were in the daytime dosing group, and the other 36 patients were in the night-time dosing group. In the daytime dosing group, a decrease in the volume of fluid intake was found at 06.00-12.00, 12.00-18.00, and 18.00-24.00 hours, and a decrease in total voided volume was found at 12.00-18.00, 18.00-24.00, and 24.00-06.00 hours with a between-group difference at 18.00-24.00 hours (coefficient = 542 mL, P = 0.01). In the night-time dosing group, an increase in voided volume per micturition was found at 06.00-12.00 and 24.00-06.00 hours with a between-group difference at 24.00-6.00 hours (coefficient = 92 mL, P = 0.003) compared with the daytime dosing group. Nonetheless, pre-treatment proportions of nocturnal polyuria did not differ from post-treatment proportions (night-time: 20% vs 20%, P = 1.00; daytime: 48% vs 42%, P = 0.48). Decreases in the number of voiding and urgency episodes at nearly all time periods and increases in the volumes at strong desire to void were also found in both groups. CONCLUSION: Night-time dosing of tolterodine ER may benefit female patients suffering from nocturia due to a greater voided volume per micturition at midnight.

Tolterodine Tartrate.

Tolterodine tartrate belongs to the family of muscarinic receptor antagonists and is indicated for the treatment of overactive urinary bladder syndrome. This chapter provides an overview of physical, analytical, and ADME profiles; highlights methods of chemical synthesis; and discusses stability of tolterodine as a free base and/or its l-tartrate salt in solution and in the solid state. The information presented in this chapter is based on the peer-reviewed literature, compendial reports (USP, EP), and authors' data. Patent literature is included only in a few instances.

Histopathologic and Urodynamic Effects of the Anticholinergic Drugs Oxybutynin, Tolterodine, and Trospium on the Bladder.

OBJECTIVES: This study aimed to evaluate the effects of intravesical instillation of the anticholinergic drugs oxybutynin, tolterodine, and trospium on bladder capacity and histopathological changes in the bladder mucosa. METHODS: The study included 20 male New Zealand white rabbits that were randomly allocated to four groups of five. In the oxybutynin, tolterodine, and trospium groups, the drugs used were 1 mg/kg of crushed tablet mixed with 5 mL of saline, instilled intravesically once per day for 4 weeks. The control group was administered only 5 mL of saline once per day for 4 weeks. Urodynamic measurement of the bladder was made before and after treatment. At the end of the treatment the animals were killed and the bladders were evaluated histopathologically. RESULTS: There were no significant differences between pre- and post-treatment bladder capacity in any of the groups (P > 0.05). Histopathological evaluation showed that the mucosal epithelium was intact and there was minor inflammation in the control group and oxybutynin group (P > 0.05), whereas there was destruction of the mucosal epithelium and findings of diffuse inflammation in the tolterodine (P = 0.014) and trospium (P = 0.014) groups. CONCLUSION: Intravesical oxybutynin treatment was observed to be safe; however, a single daily dose of oxybutynin may not be sufficient to increase bladder capacity. Intravesical use of trospium and tolterodine at high doses caused epithelial destruction and diffuse inflammation in the bladder mucosa. The irritation associated with epithelial destruction and inflammation prevented an increase in bladder capacity.

Bladder telemetry: A new approach to evaluate micturition behavior under physiological and inflammatory conditions.

AIMS: To establish a new approach to cystometry using telemetry in conscious rats and to use this technique to determine the role of conscious decision making processes with respect to the initiation of voiding in physiological, inflammatory, and painful conditions. METHODS: The pressure transducer of a telemetric transmitter was implanted in the dome of the urinary bladder. After a recovery period of at least 1 month, several investigations of urodynamic parameters were performed after diuresis activation by a pulse of furosemide. The model was characterized by tolterodine and mirabegron under physiological conditions and same animals were reused to evaluate the modification of the voiding pattern under bladder inflammation induced by cyclophosphamide. RESULTS: The quality of traces and measurement of parameters recorded telemetrically were comparable to those with conventional cystometry. Furosemide induced a reproducible transient increase of urine production and a series of voids that persisted for 60 min. Tolterodine reduced the amplitude of micturition contractions although mirabegron was devoid of any effect. Seven hours after injection of CYP, voiding frequency increased significantly and the micturition amplitude contraction was not altered. However, the mean volume voided during individual micturitions and the total voided volume decreased. During a second exposure to furosemide 24H after CYP injection, the micturition pattern returned to control, however, the micturition volume was still lower than in control. CONCLUSION: This telemetric model appears to be as accurate as previously described in conscious conventional cystometry, and allows the repeated evaluation of compounds which may modulate the voiding patterns. Neurourol. Urodynam. 36:308-315, 2017. © 2016 The Authors. Neurourology and Urodynamics published by Wiley Periodicals, Inc.

Differential effects of the enantiomers of tamsulosin and tolterodine on P-glycoprotein and cytochrome P450 3A4.

The pregnane X receptor (PXR) is a transcription factor regulating P-glycoprotein (P-gp; ABCB1)-mediated transport and cytochrome P450 3A4 (CYP3A4)-mediated metabolism of xenobiotics thereby affecting the pharmacokinetics of many drugs and potentially modulating clinical efficacy. Thus, pharmacokinetic drug-drug interactions can arise from PXR activation. Here, we examined whether the selective α1-adrenoreceptor blocker tamsulosin or the antagonist of muscarinic receptors tolterodine affect PXR-mediated regulation of CYP3A4 and of P-gp at the messenger RNA (mRNA) and protein level in an enantiomer-specific way. In addition, the effect of tamsulosin and tolterodine on P-gp activity was evaluated. We used quantitative real-time PCR, gene reporter assay, western blotting, rhodamine efflux assay, and calcein assay for determination of expression, activity, and inhibition of P-glycoprotein. The studied compounds significantly and concentration-dependently increased PXR activity in the ABCB1-driven luciferase-based reporter gene assay. We observed much stronger induction of ABCB1 mRNA by S-tamsulosin as compared to the R or racemic form. R or racemic form of tolterodine and R-tamsulosin concentration-dependently increased P-gp protein expression; the latter also enhanced P-gp efflux function in a rhodamine-based efflux assay. R-tamsulosin and all forms of tolderodine slightly inhibited P-gp. The effect on CYP3A4 expression followed the same pattern but was much weaker. Taken together, tamsulosin and tolterodine are demonstrated to interfere with P-gp and CYP3A4 regulation in an enantiomer-specific way.

Tolterodine reduces veratridine-augmented late INa, reverse-INCX and early afterdepolarizations in isolated rabbit ventricular myocytes.

AIM: The augmentation of late sodium current (INa.L) not only causes intracellular Na+ accumulation, which results in intracellular Ca2+ overload via the reverse mode of the Na+/Ca2+ exchange current (reverse-INCX), but also prolongs APD and induces early afterdepolarizations (EAD), which can lead to arrhythmia and cardiac dysfunction. Thus, the inhibition of INa.L is considered to be a potential way for therapeutic intervention in ischemia and heart failure. In this study we investigated the effects of tolterodine (Tol), a competitive muscarinic receptor antagonist, on normal and veratridine (Ver)-augmented INa.L, reverse-INCX and APD in isolated rabbit ventricular myocytes, which might contribute to its cardioprotective activity. METHODS: Rabbit ventricular myocytes were prepared. The INa.L and reverse-INCX were recorded in voltage clamp mode, whereas action potentials and Ver-induced early afterdepolarizations (EADs) were recorded in current clamp mode. Drugs were applied via superfusion. RESULTS: Tol (3-120 nmol/L) concentration-dependently inhibited the normal and Ver-augmented INa.L with IC50 values of 32.08 nmol/L and 42.47 nmol/L, respectively. Atropine (100 µmol/L) did not affect the inhibitory effects of Tol (30 nmol/L) on Ver-augmented INa.L. In contrast, much high concentrations of Tol was needed to inhibit the transient sodium current (INa.T) with an IC50 value of 183.03 µmol/L. In addition, Tol (30 nmol/L) significantly shifted the inactivation curve of INa.T toward a more depolarizing membrane potential without affecting its activation characteristics. Moreover, Tol (30 nmol/L) significantly decreased Ver-augmented reverse-INCX. Tol (30 nmol/L) increased the action potential duration (APD) by 16% under the basal conditions. Ver (20 µmol/L) considerably extended the APD and evoked EADs in 18/24 cells (75%). In the presence of Ver, Tol (30 nmol/L) markedly decreased the APD and eliminated EADs (0/24 cells). CONCLUSION: Tol inhibits normal and Ver-augmented INaL and decreases Ver-augmented reverse-INCX. In addition, Tol reverses the prolongation of the APD and eliminates the EADs induced by Ver, thus prevents Ver-induced arrhythmia.