Benefit-Risk Assessment of Tolterodine in the Treatment of Overactive Bladder in Adults

Monotherapy with tolterodine or mirabegron is insufficient for ameliorating cyclophosphamide-induced bladder overactivity in rats

Monotherapy continues to be the most common pharmacological treatment option for patients with overactive bladder (OAB), despite evidence indicating that it may have inferior efficacy compared to combination therapy. This seems to be especially true for patients with concomitant cystitis. The current study examined the effects of monotherapy with either the antimuscarinic tolterodine or the β3 agonist mirabegron on bladder overactivity induced by bladder inflammation. Further, the possible involvement of nitric oxide (NO) was studied. For this purpose, rats were pretreated with either drug for 10 days. Bladder inflammation was induced by intraperitoneal injection with cyclophosphamide, with saline serving as control. Micturition parameters were assessed in a metabolic cage. Meanwhile, urine samples were collected and further analysed for NO content. After 16 h, the animals were euthanized, and their bladders were excised and examined immunohistochemically for signs of inflammation. Cyclophosphamide treatment led to bladder overactivity and obvious signs of inflammation. Neither treatment with tolterodine nor mirabegron could significantly alleviate the induced overactivity or the observed inflammation. Further, while induction of inflammation led to a significant increase in NO production, neither drug seemed to act by further enhancing its production. On the contrary, treatment with either tolterodine or mirabegron significantly decreased NO production in cyclophosphamide treated rats. Considering previous findings showing significant improvement by combination therapy, the current study indirectly implies this as the superior treatment option. Further studies are needed to verify the involvement, or lack thereof, of NO in the mechanism of action of drugs used to treat OAB.

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

AIM

The augmentation of late sodium current (I_Na.L) not only causes intracellular Na⁺ accumulation, which results in intracellular Ca²⁺ overload via the reverse mode of the Na⁺/Ca²⁺ exchange current (reverse-I_NCX), but also prolongs APD and induces early afterdepolarizations (EAD), which can lead to arrhythmia and cardiac dysfunction. Thus, the inhibition of I_Na.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 I_Na.L, reverse-I_NCX and APD in isolated rabbit ventricular myocytes, which might contribute to its cardioprotective activity.

METHODS

Rabbit ventricular myocytes were prepared. The I_Na.L and reverse-I_NCX 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 I_Na.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 I_Na.L. In contrast, much high concentrations of Tol was needed to inhibit the transient sodium current (I_Na.T) with an IC₅₀ value of 183.03 μmol/L. In addition, Tol (30 nmol/L) significantly shifted the inactivation curve of I_Na.T toward a more depolarizing membrane potential without affecting its activation characteristics. Moreover, Tol (30 nmol/L) significantly decreased Ver-augmented reverse-I_NCX. 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 I_NaL and decreases Ver-augmented reverse-I_NCX. In addition, Tol reverses the prolongation of the APD and eliminates the EADs induced by Ver, thus prevents Ver-induced arrhythmia.

The efficacy of resiniferatoxin in prevention of catheter related bladder discomfort in patients after TURP - a pilot, randomized, open study

Background

Resiniferatoxin (RTX) has been shown to have variable efficacy in the treatment of intractable lower urinary tract symptoms and symptoms associated with neurogenic detrusor overactivity. It has also been used successfully in treating overactive bladder (OAB). In order to evaluate the potential and efficiency of RTX in treatment of catheter related bladder discomfort (CRBD) over post-operative period of transurethral resection of the prostate (TURP), we conducted the current pilot, randomized open study.

Methods

The study was comprised of 48 patients undergoing TURP in a single institute from September 2007 to September 2008. Patients were randomly divided into Group-RTX and Group-control. CRBD was classified into 4 degrees: degree 0, 1, 2, and 3. Patients with the most severed CRBD (degree-3) were treated with tolterodine.

Results

There were no statistical difference of patients' age, prostate volume, IPSS score, storage score and void score in IPSS, and QOL score between the two study groups(P=0.213, 0.356, 0.471, 0.554, 0.055 and 0.380, respectively). RTX pre-treatment reduced incidence of CRBD. 25% of the patients in RTX group had CRBD, at 6 hours/1 day and 3 days after TURP, significantly lower than the control group in which 75% of the patients during the same period (P=0.001). During the three days post-operative period, RTX also reduced severity of CRBD, compared with the control group. No patient in Group RTX sufferred CRBD of degree 3, a clear contrast to the control group in which 7 patients had degree 3 CRBD, during three days post-operative. Finally, less patients in RTX group required tolterodine, compared with control, P=0.009. Interestingly, the difference of CRBD incidence between Group RTX (50%) and control (75%) diminished 5 days after TURP, P=0.135.

Conclusions

Pretreatment with intravesical resiniferatoxin significantly reduces the incidence and severity of catheter related bladder discomfort in patients after TURP.

Tolterodine does not affect memory assessed by passive-avoidance response test in mice

Antimuscarinics are first-line pharmacotherapy for the treatment of overactive bladder. However, because central nervous system cholinergic neurotransmission is involved in cognition, and the central nervous system-permeable antimuscarinics scopolamine and oxybutynin affect memory, cognitive impairment has been noted as a possible side effect of these drugs. We evaluated the effect of tolterodine, an antimuscarinic for overactive bladder, in a mouse passive-avoidance model of memory. Mice were chosen because like humans, mice but not rats, form the pharmacologically active 5-hydroxymethyl metabolite of tolterodine, DD01. In the passive-avoidance test, tolterodine at 1 or 3 mg/kg had no effect on memory; the latency to cross and percentage of animals crossing were comparable to controls. In contrast, scopolamine induced a memory deficit; the latency to cross was decreased, and the number of animals crossing was increased. Therefore, at a dose exceeding therapeutic exposure by six-fold, tolterodine had no effect on memory in the mouse passive-avoidance model, indicating that tolterodine does not disrupt cognitive function in this testing paradigm.

Clinical Efficacy, Safety, and Tolerability of Once-Daily Fesoterodine in Subjects with Overactive Bladder

OBJECTIVE

To determine the efficacy, tolerability, and safety of fesoterodine in subjects with overactive bladder (OAB).

METHODS

This was a multicentre, randomised, double-blind, placebo- and active-controlled trial with tolterodine extended release (ER) to assess the efficacy and safety of fesoterodine. Eligible subjects (> or =18 yr) with increased micturition frequency and urgency and/or urgency urinary incontinence (UUI) were randomised to placebo, fesoterodine 4 mg, fesoterodine 8 mg, or tolterodine ER 4 mg for 12 wk. The primary efficacy variable was a change from baseline to week 12 in micturitions per 24 h. Co-primary end points included change from baseline to week 12 in UUI episodes per 24 h and Treatment Response ("yes" or "no," based on four-point treatment benefit scale). Secondary efficacy variables included mean volume voided per micturition, continent days per week, and number of urgency episodes.

RESULTS

At the end of treatment, subjects taking fesoterodine 4 and 8 mg had significant (p<0.05) and clinically relevant improvements versus placebo in the primary, co-primary, and most secondary efficacy variables. Tolterodine ER (active control) also provided significantly greater improvement than placebo for most efficacy variables, confirming the sensitivity of the study design. A more pronounced effect was observed with fesoterodine 8 mg at most end points.

CONCLUSIONS

Both doses of fesoterodine were significantly better than placebo in improving the symptoms of OAB and produced a significantly greater Treatment Response versus placebo. Efficacy was more pronounced with fesoterodine 8 mg compared with the other treatments. Active treatments were well tolerated.

The clinical efficacy of tolterodine extended-release is maintained for 24 h in patients with overactive bladder

OBJECTIVE

To assess the 24-h efficacy of tolterodine extended-release (ER) in patients with overactive bladder (OAB) and urgency urinary incontinence (UUI).

PATIENTS AND METHODS

We conducted a post hoc analysis of a 12-week, placebo-controlled trial of tolterodine-ER in patients with frequency (> or =8 voids/24 h) and UUI (> or=5 episodes/week) for > or = 6 months. Seven-day bladder diaries were used to record diary endpoints; 24-h diary data were stratified by 6-h periods beginning at midnight.

RESULTS

Compared with placebo (508 patients), tolterodine-ER (507 patients) significantly and consistently increased volume voided per void and reduced UUI episodes and micturition frequency during each interval.

CONCLUSIONS

These results indicate that tolterodine-ER maintained clinical efficacy over 24 h and should be effective for OAB symptoms without regard to whether symptoms occur during the day or at night.

Drug-induced changes in P450 enzyme expression at the gene expression level: a new dimension to the analysis of drug-drug interactions

Drug-drug interactions (DDIs) caused by direct chemical inhibition of key drug-metabolizing cytochrome P450 enzymes by a co-administered drug have been well documented and well understood. However, many other well-documented DDIs cannot be so readily explained. Recent investigations into drug and other xenobiotic-mediated expression changes of P450 genes have broadened our understanding of drug metabolism and DDI. In order to gain additional information on DDI, we have integrated existing information on drugs that are substrates, inhibitors, or inducers of important drug-metabolizing P450s with new data on drug-mediated expression changes of the same set of cytochrome P450s from a large-scale microarray gene expression database of drug-treated rat tissues. Existing information on substrates and inhibitors has been updated and reorganized into drug-cytochrome P450 matrices in order to facilitate comparative analysis of new information on inducers and suppressors. When examined at the gene expression level, a total of 119 currently marketed drugs from 265 examined were found to be cytochrome P450 inducers, and 83 were found to be suppressors. The value of this new information is illustrated with a more detailed examination of the DDI between PPARalpha agonists and HMG-CoA reductase inhibitors. This paper proposes that the well-documented, but poorly understood, increase in incidence of rhabdomyolysis when a PPARalpha agonist is co-administered with a HMG-CoA reductase inhibitor is at least in part the result of PPARalpha-induced general suppression of drug metabolism enzymes in liver. The authors believe this type of information will provide insights to other poorly understood DDI questions and stimulate further laboratory and clinical investigations on xenobiotic-mediated induction and suppression of drug metabolism.

In Vitro Preclinical Cardiac Assessment of Tolterodine and Terodiline: Multiple Factors Predict the Clinical Experience

Terodiline and tolterodine are drugs used to treat urinary incontinence. Terodiline was removed from the market in 1991 for proarrhythmia, whereas tolterodine has a generally benign clinical cardiac profile. To assess differences in the electrophysiologic actions of these drugs, we evaluated their effects on hERG current (HEK cells) and cardiac Purkinje fiber repolarization. The IC50 for hERG block (37 degrees C) by tolterodine was 9.6 nM and by terodiline was 375 nM, values near or below clinical concentrations. Tolterodine elicited concentration-dependent prolongation of the action potential duration (APD90). In contrast, terodiline depressed the action potential plateau and induced triangulation without affecting APD90. The triangulation ratios (normalized ratio of APD50 over APD90) for terodiline were 0.94 and 0.59 for 1.0 and 10 microM and for tolterodine, were 0.99 and 0.97 at 7 and 70 nM. In summary, tolterodine, a potent hERG blocker, has a benign clinical cardiac profile at therapeutic concentrations that may be due to its lack of triangulation, as well as extensive plasma protein binding. However, at supratherapeutic concentrations, preclinical data predict risk of QT prolongation. These data suggest that hERG block and triangulation are among multiple factors that must be considered in preclinical cardiac safety assessments.

Urinary incontinence: economic burden and new choices in pharmaceutical treatment

In the year 2000, an estimated 17 million community-dwelling adults in the United States had daily urinary incontinence (UI), and an additional 33 million suffered from the overlapping condition, overactive bladder. Estimates of the total annual cost of these conditions range up to 32 billion US dollar; the largest components are management costs and the expenses associated with nursing home admissions attributable to UI. In most cases, patients with UI can be treated with pharmaceutical agents, in addition to behavioral therapy. Until recently, pharmaceutical therapy for UI has been limited, especially because the adverse effects of available agents resulted in poor adherence to treatment regimens. Recent innovations in molecular design and new dosage forms of UI medications offer the promise of fewer and less severe adverse effects and, thus, better treatment outcomes for patients. Additionally, the availability of multiple agents within a therapeutic class offers health care providers a spectrum of choices with which to personalize treatment for each individual patient. New pharmacologic treatment options for UI have the potential to allow greater independence for older persons who reside at home and to delay or avoid the costs of admission to long-term care facilities. Alternate dosage forms, which include patches and sustained-release formulations, may benefit patients who have difficulty chewing, swallowing, or remembering to take medications. Although these newer products are generally more expensive than older forms of therapy, they typically have more favorable cost-effectiveness ratios. Access to these new medications for patients enrolled in public and private health care plans may help to reduce the economic and social burden of UI care.

Efficacy and tolerability of tolterodine extended-release in continent patients with overactive bladder and nocturia

OBJECTIVE

To evaluate the clinical efficacy and tolerability of tolterodine extended-release (ER) in continent patients with overactive bladder (OAB) and nocturia.

PATIENTS AND METHODS

A post hoc analysis was conducted of data from a 12-week, double-blind study of 850 patients randomized to tolterodine ER (4 mg once daily) or placebo, taken within 4 h of going to bed. Patients with a mean of > or = 8 voids/24 h were enrolled, including a mean of > or = 2.5 voids/night. Patients completed 7-day voiding diaries, and for each void an urgency rating was assessed using a 5-point scale (1, none; 5, urgency incontinence); 24-h voids were categorized by urgency rating: total (1-5), non-OAB (1-2), OAB (3-4), and severe OAB (4-5) voids. All adverse events were recorded.

RESULTS

The post hoc analysis included 513 patients (243 placebo; 270 tolterodine ER; 58% men) who were continent at baseline; 47% of 24-h voids were classed as non-OAB, and 12% as severe OAB. After 12 weeks of treatment, tolterodine ER significantly reduced mean urgency rating and 24-h OAB, severe OAB, and total voids vs placebo. Tolterodine ER did not affect normal, non-OAB voids, and there were no significant adverse events related to voiding. Other than dry mouth (tolterodine ER, 9% vs placebo, 2%), all the adverse events were reported in <3% of patients; <2% of patients receiving tolterodine ER withdrew because of adverse events.

CONCLUSIONS

In continent patients with OAB, tolterodine ER significantly improved urgency rating and reduced 24-h OAB, severe OAB, and total voids, suggesting that it is an effective and well-tolerated treatment option for this subpopulation. More studies are needed to better understand the clinical efficacy of tolterodine ER in this under evaluated group of OAB patients without incontinence.