Comparative tolerability of drug therapies used to treat incontinence and enuresis.

Drug therapy for incontinence and enuresis has met with varying degrees of success. Currently, there is no medication available that specifically targets the lower urinary tract without having untoward effects elsewhere in the body. Patients with urge incontinence are the most difficult group to treat. The agents most commonly used to treat urge incontinence, i.e. anticholinergics, musculotropics and tricyclic antidepressants, are limited in their effectiveness and have anticholinergic adverse effects. Other medications with theoretical treatment potential such as nonsteroidal anti-inflammatory drugs and calcium antagonists require more in depth clinical study before widespread use is appropriate. Although estrogen is well tolerated, its role in the treatment of incontinence in postmenopausal women may be limited. Medical treatment for stress incontinence is most successful in patients with a mild condition. Drugs with alpha-adrenergic activity alone or in combination with estrogen in postmenopausal women, are fairly effective and demonstrate few adverse effects at doses used to treat stress incontinence. Enuresis pharmacotherapy consists mainly of desmopressin and tricyclic antidepressants. Adverse effects are minimal with the doses commonly used. While the majority of patients improve with therapy, a significant portion relapse after treatment is terminated. Tolerability of a particular therapy depends on the effectiveness and adverse effects of the agent, the severity of incontinence and the general health of the patient. In general, patients are willing to accept a greater degree of inconvenience if a drug produces the desired effect. However, individualisation of therapy should be used to maximise compliance and outcome. Blinded, dose-titration studies are needed to better determine doses for optimum tolerability. Research into drugs specifically targeting the lower urinary tract may lead to more effective and well tolerated therapy for incontinence and enuresis.