Extended-release Trospium Chloride 60mg – A New Once-daily Medication for the Treatment of Overactive Bladder Syndrome

Overactive bladder syndrome (OAB) has been defined by the International Continence Society (ICS) as a symptom complex diagnosed by urinary urgency with or without urge incontinence, usually with frequency and nocturia.¹ As assessed by the European Prospective Investigation into Cancer and Nutrition (EPIC) study in several countries, the prevalence of OAB in randomly selected subjects of both sexes ≥18 years of age was similar in women and men, with rates of 12.8 and 10.8%, respectively.² With increasing age, the prevalence increases significantly, reaching 16.6% in the overall population of subjects over 40 years of age.³ Such a common condition is associated with different degrees of impairment in quality of life (mostly when the symptoms are associated with urinary incontinence and sometimes depending on culture, environment, access to medical information and many other factors), with increased co-morbidity, particularly risk of falls and bone fractures in elderly people,⁴ and a heavy economic burden on the community.^5,6


The pathophysiology of OAB is still not fully understood in view of its multifactorial nature, which involves sensory and motor components of the central nervous system (CNS), both the autonomic and somatic innervation of the detrusor muscle and internal urethral sphincter as well as sensory afferents from the urothelium. The treatment of OAB usually includes patient education and non-pharmacological measures such as bladder training and pelvic floor exercises; however, pharmacological treatment with anticholinergic drugs is becoming the mainstay of OAB therapy, at least in adult patients. By blocking muscarinic receptors in the detrusor muscle, in presynaptic nerve terminals and possibly at sensory afferent nerve terminals within the urothelium,^7,8 anticholinergic drugs are thought to reduce the involuntary detrusor contractions, thereby controlling the symptoms of OAB.


Five subtypes of muscarinic receptors, M1–M5, have been identified within the parasympathetic system, with M2 and M3 subtypes accounting for two-thirds and one-third, respectively, of the muscarinic receptors in the detrusor muscle. M3 receptors mediate smooth-muscle contraction, whereas M2 receptors may inhibit smooth-muscle relaxation mediated by β-adrenergic receptors, thus indirectly contributing to bladder contractions. Since an age-related decline in the subpopulation of M3 receptors has been observed in the human bladder, the resulting further increase in the relative percentage of M2 receptors in the detrusor muscle of elderly people may lead to speculation about their overall contribution to the micturition process.¹⁰


The use of muscarinic receptor antagonists is common in patients with OAB.^11,12 As a result of the wide distribution of muscarinic receptors in the CNS and peripheral nervous system, there have been safety concerns with respect to the ability of these drugs to penetrate the CNS and therefore potentially impair the acetylcholine-mediated cognitive functions.¹³