The efficacy and safety of oral desmopressin in children with primary nocturnal enuresis

Purpose: We confirmed findings that oral desmopressin safely decreases the number of wet nights in children with enuresis and identified doses at which acceptable responses can be obtained. Materials and Methods: We evaluated the safety and efficacy of oral desmopressin in a double-blind, placebo controlled, parallel group, randomized, multicenter trial of 193 children 6 to 16 years old with documented primary nocturnal enuresis. The study was conducted in 2 phases: 1) a 2-week dose ranging phase in which children received desmopressin (0.2, 0.4 or 0.6 mg.) or placebo at bedtime and 2) an 8-week dose titration phase that followed a 2-week placebo washout. Patients received 0.2 mg. desmopressin or placebo for the first 2 weeks and then the dose was increased in 0.2 mg. increments at 2-week intervals until the patient was completely dry or was receiving 0.6 mg. Patients were instructed to limit fluid intake. Mean decrease from baseline in the number of wet nights, percentage of responding patients and safety were assessed at 2-week intervals. Results: There was a statistically significant linear response to oral desmopressin at doses from 0.2 to 0.6 mg. during the dose ranging phase (p less than or equal to 0.05). The decrease in wet nights after 2 weeks of treatment with desmopressin was 27%; 30% and 40% at 0.2, 0.4 and 0.6 mg. doses, respectively, compared to 10% with placebo. All doses were statistically significantly different from placebo (p less than or equal to 0.05). During the dose titration phase all placebo treated and 87% of desmopressin treated patients were receiving the maximum dose of 3 tablets nightly because they had not been completely dry in the previous 2 weeks. Nevertheless, 44% of desmopressin treated patients had achieved at least a 50% reduction from baseline in the number of wet nights per 2 weeks at the lower doses of 0.2 and 0.4 mg. Most adverse events (rhinitis, pharyngitis, headache and increased cough) were mild to moderate in severity, unrelated to treatment and resolved before the study was completed. Conclusions: Oral desmopressin administered at bedtime to children with primary nocturnal enuresis was significantly better than placebo for decreasing episodes of bed-wetting (p < 0.05). A linear dose-response relationship was observed (p < 0.05). An acceptable response to treatment (50% or greater reduction from baseline in wet nights per 2 weeks) was seen at all doses of desmopressin. Oral desmopressin, up to 0.6 mg. for 8 weeks, was well tolerated.