Oral desmopressin: A randomized double-blind placebo controlled study of effectiveness in children with primary nocturnal enuresis

Purpose: Desmopressin nasal spray has proved to be efficacious treatment of primary nocturnal enuresis. Oral desmopressin tablets would be a more easily used, convenient vehicle for our patients and their parents. We evaluated the effectiveness of oral desmopressin in decreasing the number of wet nights in patients with primary nocturnal enuresis. Materials and Methods: We performed a double-blind, placebo controlled, parallel group trial of oral desmopressin in 141 children 5 to 17 years old with documented primary nocturnal enuresis at 14 sites. Patients were screened for number of wet nights for 2 weeks before study entry. A minimum of 3 wet nights weekly for 2 consecutive weeks was required for study entry. Patients were randomized to receive 200, 400 or 600 mcg. desmopressin or placebo before bedtime. Fluids were restricted 2 hours before bedtime based on body weight. The primary efficacy variable was mean decrease in the number of wet nights recorded during the last 2-week treatment period. The percentage of responding patients and mean decrease from baseline in number of wet nights at 2, 4 and 6 weeks were also assessed. Results: The decrease in wet nights was 9, 20, 30 and 36% for placebo, and 200, 400, and 600 mcg. desmopressin orally per day, respectively. The 600 mcg. dose of oral desmopressin daily was statistically significantly different (p < 0.05) from placebo in decreasing wet nights. A complete or near complete response (0 to 2 wet nights) was noted in 3, 18, 33 and 24% of the patients who received placebo, and 200, 400 and 600 mcg. oral desmopressin daily, respectively. The 400 and 600 mcg. treatment groups were statistically significantly different (p <0.05) from placebo. A less than 50% decrease in wet nights was noted in 83, 79, 64 and 61% of the patients who received placebo, and 200, 400 and 600 mcg. oral desmopressin daily, respectively. Oral desmopressin exhibited a dose response in the treatment of primary nocturnal enuresis. The linear trend for the decrease in wet nights was statistically significant (p <0.05). Conclusions: A dose of 600 mcg. oral desmopressin daily significantly decreased the mean number of wet nights when administered for 6 weeks. A higher dose may be necessary for an improved response.