Determining the optimal initial dose for Japanese patients with nocturnal polyuria using an initial dose of desmopressin 50 µg.

OBJECTIVE: There is no consistent opinion on the optimal initial dose of desmopressin for patients with nocturnal polyuria. Over a period of 12 weeks, we investigated the safety and efficacy of an initial dose of 50 µg of desmopressin for elderly men. METHODS: Eighty patients (mean age: 78.8 years) were started on an initial dose of 50 µg of desmopressin for nocturia associated with nocturnal polyuria. Safety and efficacy were evaluated after 1, 4, and 12 weeks using a frequency-volume chart, Athens Insomnia Scale, Patient Global Impression of Improvement scale, physical examination, blood tests, and a body composition analyzer. RESULTS: Along with reduction in the frequency and volume of night-time urination, improvements in hours of undisturbed sleep, nocturnal polyuria index, and International Prostate Symptom Score, and Overactive Bladder Symptom Scores on quality of life measures were also observed. Hyponatremia was observed in 15 patients (18.7%). However, only 5.0% of patients had hyponatremia after the dose was reduced to 25 µg, and the continuation rate at 12 weeks was high at 87.5%. Age and other physical factors, such as body mass index, body water content, body fat mass, and muscle mass were not significant predictors of adverse events. CONCLUSIONS: Our study suggests that an initial dose of 50 µg is more effective than a uniformly minimum dose based on factors such as age and physique. Furthermore, a high continuation rate can be achieved by appropriately reducing the dose, if adverse events occur.

[EFFICACY AND SAFETY OF INITIAL DESMOPRESSIN DOSE OF 50 µg IN ELDERLY MALE PATIENTS WITH NOCTURNAL POLYURIA].

(Introduction) Low-dose desmopressin is now available for the treatment of nocturia associated with nocturnal polyuria in men, and its usefulness in a dose-dependent manner has been reported. Since side effects such as hyponatremia have reported frequently, the initial dose has been set at 25 µg in many cases considering age and other factors. In the present study, we investigated the efficacy and safety of an initial dose of 50 µg in elderly patients. (Subjects and methods) At Chikugo city hospital, 45 patients were started on desmopressin at an initial dose of 50 µg for nocturia with nocturnal polyuria. Efficacy and safety after one and four weeks were evaluated based on bladder (micturition) diary. The investigated parameters included frequency of nocturnal urination, nocturnal polyuria index, time to first nocturnal void, first nocturnal urine volume, nocturnal urine volume, International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score (OABSS), and Athens Insomnia Scale. Physical examinations were also carried out, along with blood tests. (Results) The mean age of the patients was 78.3 years, which was higher than that reported in prior studies. After one week of treatment, there was a significant decrease in the frequency of nocturnal urination and nocturnal urine volume, as well as a prolongation of the time to first nocturnal void, improvement in nocturnal polyuria index, and improvement in IPSS, IPSS-QOL, OABSS, and Athens Insomnia Scale. In terms of safety, adverse events were observed in eight patients (17.8%), and hyponatremia was observed in seven patients (15.6%), which was comparable to the findings of prior reports. (Conclusion) Good therapeutic results were obtained in elderly patients at an initial desmopressin dose of 50 µg, indicating that the drug could be safely administered to elderly patients with regular follow-ups and appropriate withdrawal and dose reductions.