The Mechanism of Action of Drugs Affecting the Lower Urinary Tract in the Treatment of Female Urinary Incontinence

Abstract

Urinary incontinence (UI) is thought to affect more than one in ten women in the UK. Despite its prevalence the pathology of UI is poorly understood and its pharmacological treatment largely ineffective, surgical intervention remaining the most conventional treatment for many forms of incontinence. However, the possibility of effective drug therapy is an attractive alternative. The present review summarises the mechanisms by which drugs used to treat UI evoke direct effects on the organs of the lower urinary tract, and describes their clinical efficacy. The majority of these drugs act primarily by either reducing bladder pressure, inhibiting unstable contractions, or increasing outlet resistance during the filling process. The most commonly used drugs are anti-muscarinics, although the high incidence of side effects (including an increased residual volume) and the low level of improvement achieved, has heightened the need for the development of other drug therapies. However, due to the lack of information concerning the pathological causes of unstable detrusor contractions and other changes present in UI sufferers, no drugs are available which are specifically targeted at either treating the causative factors or the changes involved in UI. As pathological understanding increases, more effective pharmacological management may be achieved.