Abstract
Overactive bladder (OAB) is characterized by symptoms of urgency and urinary frequency with or without urge incontinence; it is a common disease that is most often observed in the elderly population. Pharmacological treatment with muscarinic receptor antagonists has been the most widely used treatment modality for OAB. Solifenacin shows the highest affinity for the muscarinic M3 receptor, which mediates urinary bladder contraction, and is utilized worldwide in the treatment of OAB. In our in vitro and in vivo studies, solifenacin exhibited a high bladder-selectivity profile compared with other antimuscarinic agents. It also increased bladder capacity without affecting micturition pressure and residual urine in an OAB model of rats. Recently, urgency is considered to be the result of overactivation of afferent nerves from the urinary bladder. It has been reported that afferent nerves are located adjacent to the urothelium and stimulation of the muscarinic receptors expressed on the urothelium may contribute to the activation of afferent nerves. In preclinical studies, solifenacin has been reported to produce an inhibitory effect on bladder afferent activity. It has been reported that solifenacin ameliorates all symptoms in OAB patients with good tolerability, and in particular it results in significant reduction of urgency episodes, which is the principal symptom of OAB. In addition, solifenacin significantly increases the warning time (the period from first sensation of urgency to voiding). Therefore, the pharmacological profile of solifenacin is considered contributory to its benefits of high efficacy against OAB symptoms with few adverse effects.
