Safety and efficacy of tramadol in the treatment of idiopathic detrusor overactivity: a double-blind, placebo-controlled, randomized study

Investigational Drug Therapies for Overactive Bladder Syndrome: The Potential Alternatives to Anticolinergics

Background

Overactive bladder is a high prevalent and quality of life affecting disease. The mainstay of the medical therapy is represented by antimuscarinic drugs, but their side effects markedly affect patient compliance and prompt studies on novel investigational drugs.

Methods

A systematic literature search of peer-reviewed papers and meeting abstracts published by December 2008 was performed. PubMed databank was searched for original English articles, by using the following search terms: “overactive bladder” or “detrusor overactivity” or “urinary incontinence” and “treatment”, alone and linked to any potential molecular target or novel drug cited in the literature.

Results

Effective alternative pharmacological treatments are currently scarce, but many new promising compounds are emerging which target key molecular pathways involved in micturition control. The most promising potential therapeutic targets include central nervous system GABAergic inhibitory pathway, dopaminergic and serotoninergic systems, b-adrenoceptors and cAMP metabolism, nonadrenergic-noncholinergic mechanisms such as purinergic and neuropeptidergic systems, vanilloid receptor, bladder sensory nervous terminals, nonneuronal bladder signalling systems including urothelium and interstitial cells, prostanoids, Rho-kinase and different subtypes of potassium and calcium channels.

Conclusions

Despite the enormous amount of new biologic insight, very few novel pharmacological therapies seems to have passed the proof-of-concept clinical stage. The ultimate clinical utility of new drugs will depend on the ability to exploit tissue-specific differences and disease-related changes in molecular expression/function and to improve storage phase dysfunctions without interfering with the emptying phase. Further preclinical investigations and controlled clinical trials are urgently needed in this challenging field.

Involvement of opioid receptors in inhibition of bladder overactivity induced by sacral neuromodulation in pigs: A possible action mechanism

AIMS

To determine the role of opioid receptors in the inhibition of bladder overactivity by sacral neuromodulation (SNM) in pigs, and explore the possible mechanism of SNM.

METHODS

Both implant-driven stimulators of the S3 spinal nerve were implanted in seven pigs. Naloxone and tramadol were administered. Multiple cystometrograms were performed to determine the effects of SNM and opioid receptors on the micturition reflex by infusing normal saline (NS) or acetic acid (AA).

RESULTS

AA-induced bladder overactivity significantly reduced the bladder capacity (BC) to 29.9 ± 3.9% of the NS control level (413.1 ± 55.4 mL) (P < 0.01). SNM significantly increased the BC to 39.4 ± 5.5% of the NS control level (P < 0.03). In the absence of SNM, the cumulative dose of naloxone (0.02 and 0.2 mg/kg intravenously) did not significantly change the BC (25.1 ± 3.1% and 20.2 ± 3.1% of the NS control level, respectively) (P > 0.05). In the presence of SNM, both doses of naloxone significantly reduced the BC to 27.2 ± 3.0% and 25.1 ± 2.9% of the NS control level (P < 0.05), respectively. In the absence of SNM, tramadol did not significantly change the BC (31.5 ± 3.9% of the NS control level) (P > 0.05). In the presence of SNM, tramadol significantly increased the BC to 49.1 ± 6.1% of the NS control level (P < 0.01).

CONCLUSIONS

Opioid receptors play a role in inhibition of bladder overactivity during SNM. Combining SNM with tramadol could be a novel treatment modality for overactive bladder.

Pain management in our daily practice: should we re-evaluate?

Treatment strategies of back pain are variable. We describe an unusual case of polyuria and erectile dysfunction with a short-term tramadol use. A 29-year-old man presented to our clinic with worsening lower back pain. After poor control of his pain on Non steroidal anti-inflammatory drugs, tramadol was prescribed. After 3 days of starting tramadol, he experienced significant polyuria and erectile dysfunction with inability to ejaculate or obtain orgasm. He denied any systemic symptoms. On follow-up, he reported complete resolution of his polyuria and erectile dysfunction within 24 h of stopping tramadol, in addition to satisfactory control of his pain. Polyuria and erectile dysfunction are very uncommon side effects of tramadol, reported in <1% of chronic users. This is the first case report to demonstrate such a rapid and aggressive onset of this combination of rare side effects with the complete resolution after tramadol discontinuation.

Anaesthetic effects of tiletamine-zolazepam-xylazine-tramadol combination in cats undergoing surgical sterilization

This study was conducted to evaluate the anaesthetic and physiological effects of tiletamine-zolazepam-xylazine-tramadol (TZXT) combination in cats undergoing surgical sterilization. A total of 20, 13.3 ± 2.5 months old, with a body weight of 2.4 ± 0.2 kg, male cats were used in the experiment. Cats were randomly assigned into the anaesthesia group (group A) or to the surgery group (group S). The tiletamine-zolazepam-xylazine-tramadol combination was administered with an intended dose of 2.4 mg·kg-1 tiletamine-zolazepam (TZ), 0.36 mg·kg-1 xylazine (X), and 0.8 mg·kg-1 tramadol (T) into the lateral femoral muscle. Physiological indicators including rectal temperature (RT), heart rate (HR), respiration rate (RR), haemoglobin saturation by oxygen (SpO2), mean arterial pressure (MAP), systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) were collected after baseline values (time 0). Cats were immediately given the intramuscular injection drug combination. Physiological indicators were recorded before injection of this combination and at time 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 min after administration of the tiletamine-zolazepam-xylazine-tramadol combination. In group S, castrations were performed using a closed procedure. Vomiting, excitement, apnoea, and abnormal behaviour were not observed in any cat during anaesthesia. All changes in indicators were within cardiorespiratory acceptable limits in both groups. The tiletamine-zolazepam-xylazine-tramadol combination produced satisfactory anaesthesia in cats and it will be useful not only in induction of anaesthesia but also for surgery of short duration.

Innovative pharmacotherapies for women with overactive bladder: where are we now and what is in the pipeline?

INTRODUCTION AND HYPOTHESIS

The impressive prevalence of overactive bladder (OAB) and the relevant limitations of current treatments urge the need for novel therapeutic approaches.

METHODS

A systematic literature and web search was performed to identify investigational drugs that entered the early and late phases of clinical development for women with OAB symptoms.

RESULTS

Approved pharmacological therapies for OAB (antimuscarinics, beta-3 agonists, and botulinum toxin) are evolving with the development of alternative administration methods, combination strategies, and novel compounds, expected to improve effectiveness, bladder selectivity, and dose flexibility. A wealth of investigational compounds, developed with both public and companies' indoor nonclinical disease-oriented studies, entered the early and late stages of clinical development in the last decade. Most non-anticholinergic compounds in ongoing clinical trials target central and peripheral neurotransmitter receptors involved in neurological modulation of micturition, nonadrenergic-noncholinergic mechanisms, cyclic nucleotide metabolism, different subtypes of ion channels or peripheral receptors of prostaglandins, vanilloids, vitamin D3, and opioids. Fascinating advances are ongoing also in the field of genetic therapy.

CONCLUSIONS

New pharmaceutical formulations and drug combinations are expected to be available in the next decade in order to overcome the limitations of current drugs for OAB. Although proof-of-concept, patient-oriented studies yielded disappointing results for several tentative drugs, a lot of clinical research is ongoing that is expected to provide clinicians with novel therapeutic agents in the near future.

[Neurology and the bladder: how to assess and manage neurogenic bladder dysfunction. With particular references to neural control of micturition]

Bladder dysfunctions are one of the most common features seen in the failure of the autonomic nervous system. Among those, overactive bladder (urinary urgency and frequency) worsens quality of life of the patients, and a large amount of post-voiding residual urine or urinary retention causes urinary tract infection, kidney dysfunction, and may bring renal failure. In the present paper we discussed neural control of micturition and how to assess it. Also, we proposed appropriate management of bladder dysfunction in elderly white matter lesions (a common cause of OAB) and diabetic neuropathy (a usual pathology underlying urinary retention). For OAB, anti-cholinergics are the mainstay, whereas for the pathological post-voiding residual urine or urinary retention, alpha-blockers, cholinergic agents and clean, intermittent self-catheterization are the choice. Treatment of bladder dysfunctions is the important target for maximizing patients' quality of life.

New therapies in the treatment of overactive bladder

INTRODUCTION

Overactive bladder (OAB) is a common condition which affects both men and women across many age groups with significant impact on quality of life. There is currently an armamentarium of treatment options available ranging from conservative, medical therapy to radical surgeries. Increasing understanding of OAB is resulting in the rapid development of new therapies today.

AREAS COVERED

The purpose of this article was to summarise the latest developments in non-neurogenic OAB treatment, discuss the evidence and results of current and new treatment modalities available through review of published data and results presented at recent international meetings.

EXPERT OPINION

The ultimate goal in OAB therapy is to provide good clinical efficacy, safe, non-invasive and easy to administer. There is definitely room for development of new therapies in OAB and current progress is encouraging.

Role of the endogenous opioid system in modulation of urinary bladder activity by spinal nerve stimulation

The role of the endogenous opioid system in modulation of urinary bladder activity by spinal nerve (SN) stimulation was studied in anesthetized female rats, using the rat model of isovolumetric bladder contraction. SN stimulation at a fixed frequency of 10 Hz attenuated bladder contraction frequency; the magnitude of the inhibition was directly proportional to the current intensity. Neither the κ-opioid antagonist nor-binaltorphimine (2 mg/kg iv) nor the δ-opioid antagonist naltrindole (5 mg/kg iv) attenuated the bladder inhibitory response to SN stimulation. In contrast, the μ-opioid receptor antagonist naloxone (NLX; 0.03 mg/kg iv) blocked the inhibitory responses evoked by SN stimulation at therapeutic current intensities at ≤1 × motor threshold current (Tmot). An action at spinal and supraspinal centers was further confirmed by the ability of intrathecal or intracerebroventricular administration of NLX methiodide to attenuate the bladder inhibitory effects of 1 × Tmot SN stimulation. The magnitude of SN-mediated neuromodulation using therapeutically relevant stimulation intensity (Tmot) is equivalent to 0.16 mg/kg of systemically administered morphine, which produces 50% inhibition of bladder contraction frequency. These results suggest that the inhibitory effects of lower intensity SN stimulation may be mediated through the release of endogenous μ-opioid peptides. Additionally, these data suggest that neuromodulation may offer a mode of treating the symptoms of overactive bladder with efficacy equal to the opioid drugs but without their liability for abuse and dependence.

Combination of foot stimulation and tramadol treatment reverses irritation induced bladder overactivity in cats

PURPOSE

We determined whether transcutaneous electrical foot stimulation combined with a low dose of tramadol (Sigma-Aldrich®) could completely suppress bladder overactivity.

MATERIALS AND METHODS

Repeat cystometrograms were performed in 18 α-chloralose anesthetized cats by infusing the bladder with saline or 0.25% acetic acid. Transcutaneous electrical stimulation (5 Hz) of the cat hind foot at 2 to 4 times the threshold intensity needed to induce observable toe movement was applied to suppress acetic acid induced bladder overactivity. Tramadol (1 to 3 mg/kg intravenously) was administered to enhance foot inhibition.

RESULTS

Acetic acid irritated the bladder, induced bladder overactivity and significantly decreased bladder capacity to a mean ± SE of 26% ± 5% of saline control capacity (p <0.01). Without tramadol, foot stimulation at 2 and 4 threshold intensity applied during acetic acid cystometrograms significantly increased bladder capacity to a mean of 47% ± 5% and 62% ± 6% of saline control capacity, respectively (p <0.05). Without foot stimulation, tramadol (1 mg/kg) only slightly changed bladder capacity to a mean of 39% ± 2% of saline control capacity (p >0.05), while 3 mg/kg significantly increased capacity to 85% ± 14% that of control (p <0.05). However, 1 mg/kg tramadol combined with foot stimulation increased bladder capacity to a mean of 71% ± 18% (2 threshold intensity) and 84% ± 14% (4 threshold intensity), respectively, which did not significantly differ from saline control capacity. In addition, long lasting (greater than 1.5 to 2 hours) post-stimulation inhibition was induced by foot stimulation combined with 3 mg/kg tramadol treatment.

CONCLUSIONS

This study suggests a new treatment strategy for overactive bladder by combining foot stimulation with a low dose of tramadol, which is noninvasive and has potentially high efficacy and fewer adverse effects.

Inhibition of bladder overactivity by a combination of tibial neuromodulation and tramadol treatment in cats

Our recent study in cats revealed that inhibition of bladder overactivity by tibial nerve stimulation (TNS) depends on the activation of opioid receptors. TNS is a minimally invasive treatment for overactive bladder (OAB), but its efficacy is low. Tramadol (an opioid receptor agonist) is effective in treating OAB but elicits significant adverse effects. This study was to determine if a low dose of tramadol (expected to produce fewer adverse effects) can enhance the TNS inhibition of bladder overactivity. Bladder overactivity was induced in α-chloralose-anesthetized cats by an intravesical infusion of 0.25% acetic acid (AA) during repeated cystometrograms (CMGs). TNS (5 Hz) at two to four times the threshold intensity for inducing toe movement was applied during CMGs before and after tramadol (0.3-7 mg/kg iv) to examine the interaction between the two treatments. AA irritation significantly reduced bladder capacity to 24.8 ± 3.3% of the capacity measured during saline infusion. TNS alone reversibly inhibited bladder overactivity and significantly increased bladder capacity to 50-60% of the saline control capacity. Tramadol administered alone in low doses (0.3-1 mg/kg) did not significantly change bladder capacity, whereas larger doses (3-7 mg/kg) increased bladder capacity (50-60%). TNS in combination with tramadol (3-7 mg/kg) completely reversed the effect of AA. Tramadol also unmasked a prolonged (>2 h) TNS inhibition of bladder overactivity that persisted after termination of the stimulation. The results suggest a novel treatment strategy for OAB by combining tibial neuromodulation with a low dose of tramadol, which is minimally invasive with a potentially high efficacy and fewer adverse effects.

Drugs and future candidates

Antimuscarinic drugs are still first-line treatment for the symptoms of overactive bladder (OAB) and are associated with good initial response rates. Adverse effects and decreasing efficacy over the longer term do, however, limit their overall effectiveness. As such, alternatives to antimuscarinics are needed. The recognition of the functional contribution of the urothelium, the spontaneous myocyte activity during bladder filling, and the diversity of nerve transmitters involved in the symptoms of the OAB has sparked interest in pharmacologic manipulation of both peripheral and central pathophysiology. Some of the treatments currently under investigation are discussed in this review.

Etiology and treatment of overactive bladder in women

Overactive bladder (OAB) is a condition that affects millions of women in the United States (US). Although the etiology is largely unknown, risk factors include Caucasian race, insulin-dependent diabetes mellitus, and history of depression. Patients present with urgency with or without urinary incontinence and often have urinary frequency and nocturia. Most patients can be evaluated in the office setting utilizing simple testing. Current treatments consist of behavioral/lifestyle modification, usually in combination with antimuscarinic drug therapy. Improvements in the adverse effect profiles of antimuscarinic drugs have positively impacted quality of life. When appropriately evaluated, most patients presenting to primary care providers can be effectively treated.

Emerging drugs for treatment of urinary incontinence

IMPORTANCE OF THE FIELD

Urinary incontinence (UI) is a common problem and there are so many advances done in the field to help treat this common and distressing condition.

AREAS COVERED IN THIS REVIEW

In this article we have tried to give an overview about current and emerging drugs available for the management of UI. WHAT THE READERS GAIN: Reading the article will help to fill the knowledge gap regarding drugs available for treatment of UI.

TAKE HOME MESSAGE

Anti-muscarinic drugs remain the first-line treatment of overactive bladder (OAB) and a favorable efficacy/tolerability:safety ratio can be confirmed, but adverse effects and decreasing compliance remains an issue. Promising new alternatives are emerging but require further controlled studies to confirm their place in treatment of OAB. Surgery is still the mainstay for treatment of stress incontinence although duloxetine is the only drug licensed for this indication.

Pharmacologic management of urinary incontinence, voiding dysfunction, and overactive bladder

Most drugs used in the treatment of urinary incontinence and voiding dysfunction in women modulate neuromuscular transmission in the urethra and bladder. Pharmacotherapy is the mainstay of treatment for overactive bladder. Although several different antimuscarinic medications are available for the treatment of overactive bladder, most have similar efficacy and tolerability. Pharmacotherapy has a limited role in the management of stress incontinence and voiding dysfunction in women. Newer drugs that target different mechanisms of action are being developed for the treatment of urinary incontinence and voiding dysfunction in women.

Prospective pharmacologic therapies for the overactive bladder

Lower urinary tract symptoms (LUTS), overactive bladder syndrome (OAB) and detrusor overactivity (DO) are all conditions that can have major effects on quality of life and social functioning. Antimuscarinic drugs are first-line treatment-they often have good initial response rates, but adverse effects and decreasing efficacy cause long-term compliance problems, and alternatives are needed. The recognition of the functional contribution of the urothelium, the spontaneous myocyte activity during bladder filling, and the diversity of nerve transmitters has sparked interest in both peripheral and central modulation of LUTS/OAB/DO pathophysiology. There may be several new possibilities to treat LUTS/OAB/DO. β(3)-AR agonists (YM178), PDE 5 inhibitors (sildenafil, tadalafil, vardenafil), vitamin D analogs (elocalcitol), combinations (α(1)-AR antagonist + antimuscarinic), and drugs with a central mode of action (tramadol, aprepitant) all have Randomized controlled trial (RCT) documented efficacy. Which of these therapeutic principles will be developed to clinically useful treatments remains to be established.

Emerging pharmacological targets in overactive bladder therapy: experimental and clinical evidences

Antimuscarinics are the mainstay of the medical therapy for overactive bladder, but their side effects and often modest success have prompted studies on novel pharmacological approaches. In this paper, we give a systematic literature review of peer-reviewed papers on the subject. Effective nonantimuscarinic treatments are currently scarce, but many new promising compounds are emerging, which target key molecular pathways involved in micturition control. The most promising potential therapeutic targets include: nervous GABAergic, glycinergic, dopaminergic, and serotonergic systems; b-adrenoceptors and cAMP metabolism; nonadrenergic-noncholinergic mechanisms such as purinergic and neuropeptidergic systems; vanilloid receptors; bladder afferent nerves; nonneuronal bladder signaling systems including urothelium and interstitial cells; prostanoids; Rho-kinase; and different subtypes of potassium and calcium channels. Despite the enormous amount of new biologic insight, very few drugs with mechanism of action other than antimuscarinics have passed as yet the proof-of-concept stage. Further preclinical and clinical studies are urgently needed in this rapidly moving field.

LUTS treatment: Future treatment options

Lower urinary tract symptoms (LUTS) are commonly divided into storage, voiding, and postmicturition symptoms, and may occur in both men and women. Male LUTS have historically been linked to benign prostatic hyperplasia (BPH), but are not necessarily prostate related. The focus of treatment for LUTS has thus shifted from the prostate to the bladder and other extraprostatic sites. LUTS include symptoms of the overactive bladder (OAB), which are often associated with detrusor overactivity. Treatment for LUTS suggestive of BPH has traditionally involved the use of alpha(1)-adrenoceptor (AR) antagonists; 5alpha-reductase inhibitors; and phytotherapy-however, several new therapeutic principles have shown promise. Selective beta(3)-adrenoceptor agonists and antimuscarinics are potentially useful agents for treating LUTS, particularly for storage symptoms secondary to outflow obstruction. Other agents of potential or actual importance are antagonists of P2X(3) receptors, botulinum toxin type A, endothelin (ET)-converting enzyme inhibitors, and drugs acting at vanilloid, angiotensin, and vitamin D(3) receptor sites. Drugs interfering with the nitric oxide/cGMP-cAMP pathway, Rho-kinase and COX inhibitors, as well as drugs targeting receptors and mechanisms within the CNS, are also of interest and deserving of further study for the treatment of LUTS.