Pharmacokinetics and toxicity of antimuscarinic drugs for overactive bladder treatment in females

HSPiP, Computational, and Thermodynamic Model-Based Optimized Solvents for Subcutaneous Delivery of Tolterodine Tartrate and GastroPlus-Based In Vivo Prediction in Humans: Part I

Tolterodine tartrate (TOTA) is associated with adverse effect, high hepatic access, varied bioavailability, slight aqueous solubility, and short half-life after oral delivery. Hansen solubility parameters (HSP, HSPiP program), experimental solubility (T = 298.2 to 318.2 K and p = 0.1 MPa), computational (van't Hoff and Apelblat models), and thermodynamic models were used to the select solvent(s). HSPiP predicted PEG400 as the most suitable co-solvent based on HSP values (δd = 17.88, δp = 4.0, and δh = 8.8 of PEG400) and comparable to the drug (δd = 17.6, δp = 2.4, and δh = 4.6 of TOTA). The experimental mole fraction solubility of TOTA was maximum (xe = 0.0852) in PEG400 confirming the best fit of the prediction. The observed highest solubility was attributed to the δp and δh interacting forces. The activity coefficient (ϒi) was found to be increased with temperature. The higher values of r2 (linear regression coefficient) and low RMSD (root mean square deviation) indicated a good correlation between the generated "xe" data for crystalline TOTA and the explored models (modified Apelblat and van't Hoff models). TOTA solubility in "PEG400 + water mixture" was endothermic and entropy-driven. IR (immediate release product) formulation can be tailored using 60% PEG400 in buffer solution for 2 mg of TOTA in 0.25 mL (dosing volume). The isotonic binary solution was associated with a pH of 7.2 suitable for sub-Q delivery. The approach would be a promising alternative with ease of delivery to children and aged patients.

A muscarinic receptor antagonist reverses multiple indices of diabetic peripheral neuropathy: preclinical and clinical studies using oxybutynin

Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.

The Impact of Polypharmacy on Management of Lower Urinary Tract Symptoms in Parkinson's Disease

Lower urinary tract (LUT) symptoms are a common presentation of autonomic dysfunction in Parkinson's disease (PD). Symptoms significantly impact quality of life and are associated with worsening of motor symptoms and increased risk for falls. Different medical co-morbidities can often contribute to LUT symptoms, and a thorough evaluation therefore becomes essential. The effects of medications used for Parkinson's disease and other co-existing medical co-morbidities on LUT symptoms is often underestimated. Treatment options include behavioural therapy, oral agents such as antimuscarinic and beta-3 receptor agonist agents, botulinum toxin and neuromodulation. The first-line oral agents cause adverse effects that may exacerbate pre-existing Parkinson's disease-related symptoms. Furthermore, these oral agents can interact with other medications used in Parkinson's disease, and the challenges posed by interactions on pharmacological effects and metabolism are discussed. Knowledge about drug interactions can help in effective management of such patients and mitigate the risks for developing adverse effects.

Management of use of urinary antimuscarinics and alpha blockers for benign prostatic hyperplasia in older adults at risk of falls: a clinical review

PURPOSE

We aimed to outline the existing information and the underlying mechanisms of risk of falls associated with the use of urinary antimuscarinics for overactive bladder (OAB) or alpha-blockers for benign prostatic hyperplasia (BPH) in older adults. In addition, we aimed to provide assistance to clinicians in decision-making about (de-)prescribing these drugs in older adults.

METHODOLOGY

Based on a literature search in PubMed and Google Scholar, we reviewed the literature, and identified additional relevant articles from reference lists, with an emphasis on the most commonly prescribed drugs in OAB and BPH in older patients. We discussed the use of bladder antimuscarinics and alpha-blockers, their potential side effects related to falls, and the deprescribing of these drugs in older adults.

RESULTS

Urinary urgency or incontinence and lower urinary tract symptoms due to untreated OAB and BPH contribute to fall risk. On the other hand, the use of bladder antimuscarinics and alpha-blockers is also related to fall risk. They contribute to (or cause) falling through dizziness, somnolence, visual impairment, and orthostatic hypotension while they differ in their side-effect profiles regarding these problems. Falls are common and can cause a remarkable amount of morbidity and mortality. Thus, preventive measures should be taken to lower the risk. If the clinical condition allows, withdrawal of bladder antimuscarinics and alpha-blockers is recommended in fall-prone older adults. There are practical resources and algorithms that guide and assist clinicians in deprescribing these drug groups.

CONCLUSIONS

The decision to prescribe or deprescribe these treatments in patients at high risk of falls should be individualized. In addition to explicit tools that are helpful for clinical decision-making in (de-)prescribing these drugs, STOPPFall (a recently developed expert-based decision aid specifically aiming to prevent falls) is present to assist prescribers in attaining decisions.

The cognitive effect of anticholinergics for patients with overactive bladder

Overactive bladder (OAB) is often treated with medications that block the cholinergic receptors in the bladder (known as anticholinergics). The effect of this medication class on cognition and risk of dementia has been increasingly studied over the past 40 years after initial studies suggested that the anticholinergic medication class could affect memory. Short-term randomized clinical trials demonstrated that the administration of the anticholinergic oxybutynin leads to impaired memory and attention, and large, population-based studies showed associations between several different anticholinergic medications and dementia. However, trials involving anticholinergics other than oxybutynin have not shown such substantial effects on short-term cognitive function. This discordance in results between short-term cognitive safety of OAB anticholinergics and the long-term increased dementia risk could be explained by the high proportion of patients using oxybutynin in the OAB subgroups of the dementia studies, or a study duration that was too short in the prospective clinical trials on cognition with other OAB anticholinergics. Notably, all studies must be interpreted in the context of potential confounding factors, such as when prodromal urinary symptoms associated with the early stages of dementia lead to an increase in OAB medication use, rather than the use of OAB medication causing dementia. In patients with potential risk factors for cognitive impairment, the cautious use of selected OAB anticholinergic agents with favourable physicochemical and pharmacokinetic properties and clinical trial evidence of cognitive safety might be appropriate.

Gender specific pharmacokinetic and pharmacodynamic considerations for antimuscarinic drugs for overactive bladder treatment

Introduction: Overactive bladder (OAB) has a heterogeneous presentation that varies between individuals and by gender. Treatment with antimuscarinic medications is standard first line pharmacotherapy for most patients with OAB. However, gender specific differences in the pharmacokinetics and pharmacodynamics of antimuscarinic therapy are often overlooked and not discussed.Areas covered: This review will explore differences by gender between the presentation and treatment of OAB. We will discuss the differences between sexes in terms of lower urinary tract anatomy, muscarinic receptors, and hormone variation. The effect of antimuscarinics on males and females as well as adherence and persistence patterns will be reviewed in order to fully review all available literature on the gender specific pharmacokinetic and pharmacodynamic considerations for antimuscarinic use in the treatment of OAB.Expert opinion: Despite extensive research into various antimuscarinic formulations and therapeutic regimens for the treatment of OAB, identification of gender specific pharmacokinetic and pharmacodynamics considerations remains scant. As our knowledge and understanding of OAB, muscarinic receptors, and antimuscarinic medications evolve, we will hopefully be better able to understand and implement gender-specific and genomic-sprecific treatment regimens and considerations for improved clinical outcomes.

Cognitive and mood side effects of lower urinary tract medication

Introduction: Muscarinic receptor antagonists, 5α-reductase inhibitors and α₁-adrenoceptor antagonists are frequently used drug classes for the treatment of lower urinary tract symptoms including those of overactive bladder syndrome and benign prostatic enlargement/benign prostatic obstruction. Areas covered: The authors review the evidence for adverse effects of these drug classes on cognitive function, mood and other functions of the central nervous system and discuss such effects against the evidence for mechanistic plausibility. Expert opinion: Muscarinic antagonists carry a risk for impaired cognition and other brain functions that differs quantitatively between compounds, being highest with oral formulations of oxybutynin. 5□-Reductase inhibitors can cause depressive symptoms even at low doses and starting several months after discontinuation of treatment. The evidence for α₁-adrenoceptor antagonists and specifically tamsulosin to cause dementia is controversial and lacks mechanistic plausibility. We recommend that physicians treating patients with lower urinary tract symptoms carefully monitor mental status prior to prescribing and periodically thereafter.

Cardiovascular effects of antimuscarinic agents and beta3-adrenergic receptor agonist for the treatment of overactive bladder

INTRODUCTION

Overactive bladder (OAB) syndrome is common in the general population, particularly in elderly patients. Antimuscarinic drugs (AMs) are considered the mainstay pharmaceutical treatment of OAB whereas β3-adrenoceptor agonists, such as mirabegron, represent a good alternative. Owing to the important role of muscarinic and β3 receptors in cardiovascular (CV) tissue and to the fact that OAB patients often have CV comorbidities, the safety-profile of these drugs constitute an important challenge.

AREAS COVERED

The aim of this review is to evaluate the CV effects of AMs and mirabegron in OAB. A systematic literature search from inception until December 2017 was performed on PubMed and Medline.

EXPERT OPINION

AMs are generally considered to have good CV safety profile but, however, they may cause undesirable adverse events, such as dry mouth, constipation. CV AEs are rare but noteworthy, the most common CV consequences related to the use of these drugs are constituted by an increase in HR and QT interval. Mirabegron has similar efficacy and tolerability to AMs but causes less adverse events, with either modest hypertension and modest increase in HR (<5 bpm) being the most commonly reported.

Tropane alkaloids as substrates and inhibitors of human organic cation transporters of the SLC22 (OCT) and the SLC47 (MATE) families

Tropane alkaloids and their derivatives are anticholinergic drugs with narrow therapeutic range. Here we characterize the organic cation transporters from the SLC22 (OCT1, OCT2, and OCT3) and the SLC47 families (MATE1 and MATE2-K) as potential mediators of the renal and extra-renal excretion, the two major roads of elimination of these substances. All analyzed compounds inhibited and the quaternary amine derivatives ipratropium and trospium were strongly transported by OCTs and MATEs. Overexpression of OCTs or MATEs in HEK293 cells resulted in an up to 63-fold increase in the uptake of ipratropium (Km of 0.32 μm to OCT2 and Vmax of 3.34 nmol×mg protein-1×min-1 to MATE1). The transcellular transport of ipratropium was 16-fold higher in OCT2-MATE1 and 10-fold higher in OCT1-MATE1 overexpressing compared to control MDCKII cells. Genetic polymorphisms in OCT1 and OCT2 affected ipratropium uptake and clinically relevant concentration of ondansetron and pyrithiamine inhibited ipratropium uptake via MATEs by more than 90%. This study suggests that OCT1, OCT2 and MATEs may be strongly involved in the renal and extra-renal elimination of ipratropium and other quaternary amine alkaloids. These substances have a notoriously narrow therapeutic range and the drug-drug interactions suggested here should be further critically evaluated in humans.

Protocol for a prospective observational study of cortical lower urinary tract control changes following intradetrusor injection of botulinum toxin-A in patients with multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a severe debilitating disease that affects patients' quality of life. Up to 90% of patients with MS will develop lower urinary tract dysfunction within the first 18 years of the disease. If oral pharmacotherapy with anticholinergics, behavioural modifications and pelvic floor physical therapy are unsuccessful, intradetrusor injection of botulinum toxin-A (OnaBotA; Botox Allergan, Dublin, Ireland) is a highly effective option for these patients. The local effects of OnaBotA are well understood, but not much is known of its afferent/sensory effects while treating the end organ. Our study will use functional MRI (fMRI) and task-related blood oxygen level-dependent signals to evaluate patients with MS and neurogenic detrusor overactivity (NDO) prior to, and after, intradetrusor injection of OnaBotA with simultaneous urodynamic evaluation. Urinary concentration of brain-derived neurotrophic factor and nerve growth factor will also be collected since it has been shown that patients with an overactive bladder have higher concentrations of these neuropeptides.

METHODS AND ANALYSIS

Female patients with MS and lower urinary tract symptoms who previously have undergone urodynamic screening and are refractory to conservative and oral pharmacotherapy management for NDO and are interested in OnaBotA intradetrusor injection will be invited to participate in the study. An fMRI will be performed preintradetrusor injection and postintradetrusor injection of OnaBotA with simultaneous MRI compatible with material urodynamics. Images will be collected and analysed accordingly.

ETHICS AND DISSEMINATION

All of the patients are properly consented before enrolling in this study that has been previously approved by the Institutional Review Board. Results of neural connectivity activation will be presented at national and international meetings and published in scholarly journals.

Is mirabegron equally as effective when used as first- or second-line therapy in women with overactive bladder?

INTRODUCTION AND HYPOTHESIS

No previous studies have investigated the efficacy of mirabegron 50 mg as the first-line therapy in OAB patients. Hence, the primary objective of this study was to evaluate the efficacy of mirabegron in treatment-naive patients in comparison with those who had discontinued antimuscarinic therapy because of insufficient efficacy.

METHODS

All consecutive women who had pure OAB symptoms (including urgency with or without urgency incontinence and frequency) for at least 3 months were considered for this study. Women were divided into two groups: women without any previous pharmacological treatment for OAB (group 1) and women with a previous history of failed antimuscarinics therapy (group 2).

RESULTS

At 3-month follow-up, the objective results on the basis of the frequency-volume chart showed a significant improvement in both groups. Furthermore, a significant reduction in the Overactive Bladder Questionnaire Short Form (OABq-SF) score and in the Indevus Urgency Severity Scale (IUSS) questionnaire were reported in both groups. However, the improvement in objective and subjective outcomes was superior in group 1 to that in group 2.

CONCLUSIONS

Mirabegron is efficacious in improving OAB symptoms in both naïve patients and those who discontinued primary antimuscarinic therapy; however, its efficacy is superior when prescribed as first-line therapy.

An overlooked effect of systemic anticholinergics: alteration on accommodation amplitude

AIM

To investigate the effect of oral solifenacin succinate, tolterodine-L-tartarate and oxybutinin hydrochloride (HCl) on accommodation amplitude.

METHODS

Female overactive bladder syndrome (OAB) patients who were planned to use oral anticholinergics, patients that uses solifenacin succinate 5 mg (Group I, n=25), tolterodine-L-tartarate 4 mg (Group II, n=25), and oxybutinin HCl 5 mg b.i.d (Group III, n=25) and age matched healthy female subjects (Group IV, n=25) were recruited and complete ophthalmological examination and accommodation amplitude assessment were done at baseline and 4wk after initiation of treatment.

RESULTS

The mean age of 100 consecutive female subjects was 51.6±5.7 (40-60)y and there were no statistically significant difference with regard to the mean age (P=0.107) and baseline accommodation amplitude (P=0.148) between study groups. All treatment groups showed a significant decrease in accommodation amplitude following a 4-week course of anticholinergic treatment (P=0.008 in Group I, P=0.002 in Group II, P=0.001 in Group III), but there was no statistically significant difference in Group IV (P=0.065).

CONCLUSION

A 4-week course of oral anticholinergic treatment have statistically significant effect on accommodation amplitude. Clinicians should avoid both overestimating this result, as this would unnecessarily restrict therapeutic possibilities, and also underestimating it which may lead to drug intolerance.

Mirabegron in the treatment of overactive bladder

INTRODUCTION

Mirabegron is a selective β3-adrenergic receptor agonist recently developed for the treatment of patients with overactive bladder (OAB), which offers an alternative pharmacological option to the well-established treatment with antimuscarinics (AMs).

AREAS COVERED

This review offers an explanation of the mechanism of action, of the pharmacokinetics and pharmacodynamics of mirabegron and gives readers a complete overview of Phase II and III studies on the clinical efficacy, tolerability and safety of this agent in the setting of OAB treatment.

EXPERT OPINION

Both Phase II and III trials have shown that mirabegron is efficacious and safe in treating patients with OAB. Future research should focus on the assessment of mirabegron concentrations in the CNS and on the evaluation of the potential of the combination of mirabegron with AMs. Another field for future research is represented by the investigation of the interaction of mirabegron with CYP2D6 inhibitors. Furthermore, current literature completely lacks studies on the efficacy and safety of mirabegron in the pediatric population and such trials are awaited.

Safety and tolerability of the β3 -adrenoceptor agonist mirabegron, for the treatment of overactive bladder: results of a prospective pooled analysis of three 12-week randomised Phase III trials and of a 1-year randomised Phase III trial

AIMS

To evaluate the safety and tolerability of the β3 -adrenoceptor agonist, mirabegron, in patients with overactive bladder (OAB).

METHODS

Tolerability and safety data from three 12-week, randomised, placebo-controlled, double-blind, Phase III trials (Studies 046, 047 and 074) were pooled by treatment group. The three studies were of a similar design, although the assessed doses of mirabegron [25, 50 or 100 mg once daily (qd)] varied, and tolterodine extended release (ER) 4 mg was included as an active-control arm in Study 046 only. Tolerability and safety data from a 1-year, randomised, double-blind, Phase III trial (Study 049) are also presented. Safety variables included the incidence and severity of treatment-emergent adverse events (TEAEs), vital signs and electrocardiogram data.

RESULTS

Mirabegron (25, 50 or 100 mg qd) was safe and well-tolerated in patients with OAB over 12-week (n = 2736) and 1-year (n = 1632) periods. The incidence of TEAEs and treatment discontinuations as a result of TEAEs was low; the majority were mild in severity and few were serious. Hypertension, nasopharyngitis and urinary tract infection were the most common TEAEs with mirabegron. The mirabegron tolerability profile was similar to that seen with placebo and tolterodine ER 4 mg, except for dry mouth, which occurred, on average, five times less frequently with mirabegron than tolterodine ER 4 mg. In the pooled 12-week analysis, mirabegron 50 mg was associated with placebo-adjusted mean increases of 0.4-0.6 mmHg in blood pressure and approximately one beat per minute in pulse rate, both reversible upon treatment discontinuation. The incidence of Major Adverse Cardiovascular Events as adjudicated by an independent cardiovascular committee was low and similar across treatment groups.

CONCLUSION

The favourable tolerability profile of mirabegron in patients with OAB may allow improved treatment compliance compared with antimuscarinics, with important implications for patient outcomes.

Bioanalytical method for quantification of Solifenacin in rat plasma by LC-MS/MS and its application to pharmacokinetic study

Background

Solifenacin succinate is a competitive muscarinic acetylcholine receptor antagonist used in the treatment of overactive bladder with or without urge incontinence.

Methods

Liquid chromatography–tandem mass spectrometry method was used for quantification of Solifenacin (SF) in rat plasma. Solifenacin-d5 (SFD5) used as an internal standard. Chromatographic separation was performed Gemini-NX C18, 50 × 4.6 mm, 5 µm, 110 Å column. Mobile phase composed of 5 mM Ammonium formate, pH 3.0: methanol (20:80 v/v), with 0.4 mL/min flow-rate. Drug and IS were extracted by Liquid- liquid extraction method. SF and SFD5 were detected with proton adducts at m/z 363.2®193.2 and 368.2®198.2 in multiple reaction monitoring (MRM) positive mode respectively. The method was validated with the correlation coefficients of (r2) ≥ 0.9975 over a linear concentration range of 0.1-100.0 ng/mL.

Results

This method demonstrated intra and inter-day precision within 1.09 to 4.84 and 1.75 to 7.68 % and accuracy within 101.21 to 106.67 and 97.94 to 104.79 % for SF.

Conclusions

This method is successfully applied in the Pharmacokinetic study of rat plasma.

Important drug–drug interactions for treatments that target overactive bladder syndrome

INTRODUCTION AND HYPOTHESIS

Overactive bladder (OAB) is the term used to describe the symptom complex of urinary urgency,usually accompanied by frequency and nocturia, with or without urgency urinary incontinence, in the absence of urinary tract infection or other obvious pathology. It is a common distressing condition that significantly impairs quality of life(QoL). After lifestyle advice and bladder retraining,antimuscarinic drugs are most commonly used to treat OAB.

METHODS

The antimuscarinics in common use are all metabolised through differing mechanisms. Therefore, the risk of an enhanced drug effect is increased when the potentially interacting substrates compete for the same metabolic pathways. The aim of this review is to provide an overview on potential drug–drug interactions with special emphasis on high-risk groups and clinically important consequences of these interactions

RESULTS AND CONCLUSION

Knowledge of current important drug interactions is vital whilst prescribing antimuscarinics, particularly in high-risk groups. Novel therapies, such as beta 3 agonists or alternative drug delivery systems, such as the oxybutynin vaginal ring, might provide alternative options where these interactions are unavoidable.

Cardiovascular effects of antimuscarinic agents in overactive bladder

INTRODUCTION

The potential impact of antimuscarinics (AMs) on cardiac function is a major concern in the treatment of overactive bladder (OAB) patients, especially in older ones who are likely to present cardiovascular (CV) comorbidities and other risk factors that may predispose them to the adverse cardiac effects of this therapy.

AREAS COVERED

This article aims to review the literature on the impact on the CV system of AMs used in the treatment of OAB, giving a comprehensive explanation of the pathogenetic mechanisms of AMs' effects on CV system and the impact of each AM drug on cardiac function.

EXPERT OPINION

Although the CV safety of AM drugs seems to be good, evidence provided in this manuscript does not allow to exclude an increase in HR, QT prolongation or an increase in the CV risk due to drug-drug interactions in OAB patients who are usually elderly and have comorbidities. Clinical and electrocardiographic monitoring may be necessary throughout the administration period in selected populations such as patients aged > 80 years, those with coronary heart disease or congestive heart failure. Further studies are needed to understand whether the most recently developed AM drugs, such as imidafenacin, are safer than the old ones.

Overactive bladder, differential diagnosis, and clinical utility of fesoterodine

Overactive bladder is a symptom syndrome with urgency, frequency and, in many cases, nocturia. Urge incontinence is not present in all. There is no direct correlation with detrusor overactivity, an objective finding during urodynamic testing where involuntary contractions can be noticed. In the pathophysiology, much more attention has been given to the afferent/sensory arm of the micturition reflex in the last decade. Anatomical and infectious causes have to be diagnosed or ruled out. Diagnosis of overactive bladder is made mostly by history-taking, but other tests can be necessary in specific patients. Treatment consists of behavioral measures, a good explanation of the condition, training, and pelvic floor physiotherapy. Drugs are often used. Until recently, antimuscarinic drugs have been the mainstay of pharmacological therapy. Fesoterodine is a newer antimuscarinic agent which is more pharmacodynamically stable then tolterodine. Fesoterodine has been extensively researched using different dosages and compared with placebo and tolterodine, in different age groups, and under different conditions. Fesoterodine is superior to placebo and to tolterodine in the short term and long term. Its safety is very acceptable.