[INITIAL TREATMENT OF NOCTURIA CAUSED BY NOCTURNAL POLYURIA WITH LOW-DOSE DESMOPRESSIN]

(Objective) Nocturia, an important male lower urinary tract symptom (LUTS), is often difficult to treat. Herein, we report our experience of the initial treatment of nocturia with the novel drug desmopressin. (Subjects and methods) Subjects included 25 patients with LUTS treated with desmopressin who had the chief complaint of nocturia. Before treatment, the frequency of nocturnal urination (≥2) and nocturnal polyuria index (≥0.33) were confirmed based on the urination diary for ≥ 72 h. Before sleep, 25 or 50 mg desmopressin (Minirin^® Melt OD tablets) was administered once daily. The frequency of nocturnal urination, volume of nocturnal urine, time from falling asleep to first urination, first urinary volume after falling asleep, nocturnal polyuria index, International Prostate Symptom Score (IPSS), quality of life index, Overactive Bladder Symptom Score, and residual urine volume were comparatively evaluated before and 4 weeks after treatment. Treatment effect was self-evaluated by patients 4 weeks after the treatment. Safety was evaluated by interview and blood testing 1 and 4 weeks after the treatment. (Results) Decrease in the frequency of nocturnal urination and improvement in IPSS were observed. According to self-evaluation of the treatment, 72.6% of the patients considered the treatment efficacious. Regarding safety, adverse events were observed in 28% of the patients, particularly hyponatremia (12% of the patients). (Conclusion) Desmopressin is a potential key drug for the treatment of nocturia caused by nocturnal polyuria.