Nocturia: etiology, diagnosis, and treatment.

Voiding at night, or nocturia, is a common reason for interrupted sleep in the adult population. The condition affects both men and women, with an incidence that increases dramatically with age. Nocturia has a negative impact on quality of life, affecting both morbidity and mortality. Effective diagnosis of the condition is dependent on a clear understanding of its underlying etiology. In general, the causes of nocturia fall into three categories: diurnal polyuria, nocturnal polyuria, and low bladder capacity. In some individuals, however, nocturnal polyuria and low bladder capacity may both contribute to the overall symptomatology of nocturia. Addressing any underlying conditions that contribute to nocturia is the first step in treating the condition. Lifestyle and behavioral changes may provide benefit in some individuals, but for many, the only option is pharmacotherapy. Antimuscarinic agents are first-line therapies for overactive bladder and are often used in the management of nocturia. Pharmacological and physicochemical differences between available antimuscarinic agents, however, translate into different safety and tolerability profiles, which may make some agents more suitable for use in certain populations, including the elderly. Careful selection of the most appropriate antimuscarinic medication is therefore central in optimizing treatment outcomes.