Desmopressin, a synthetic analogue of the antidiuretic hormone (ADH), has been used for many years to treat diabetes insipidus and primary nocturnal enuresis.More recently, it is also known to be effective against nocturia with NP by decreasing night-time urine production.However, it may be associated with an increased risk of developing hyponatremia due to water retention, especially in elderly patients.In the present study, we investigated the safety and efficacy of oral desmopressin for the treatment of mixed nocturia in patients with both NP and a low NBC.