• To evaluate the efficacy of desmopressin administered as a melt tablet compared to placebo in terms of percentage baseline reduction in the number of wet nights. [ Time Frame: 14 days of screening plus 54 days of treatment ] [ Designated as safety issue: No ]
• To evaluate the efficacy of desmopressin administered as a melt tablet compared to placebo in terms of the proportion of full, partial and non-responders. [ Time Frame: 14 days of screening plus 54 days of treatment ] [ Designated as safety issue: No ]
• To investigate the safety and tolerability of desmopressin, administered as a melt tablet compared to placebo, for all doses tested. [ Time Frame: 14 days of screening plus 54 days of treatment ] [ Designated as safety issue: Yes ]

The purpose of this study is to determine whether desmopressin administered as a melt tablet is effective in reducing the number of wet nights in children and adolescents who suffer from bedwetting.

Primary nocturnal enuresis (PNE), or bedwetting, is a common childhood urological disease. Factors contributing to nocturnal enuresis include nocturnal polyuria due to, at least in part, a relative deficiency of antidiuretic hormone arginine vasopressin (AVP) which has been supported by the finding that some enuretic children lack a nocturnal increase in endogenous AVP secretion. Desmopressin, a synthetic, structural analogue of AVP, selective for V2-receptors and with a longer half life than the natural hormone, has been found to be especially beneficial in PNE subjects with nocturnal polyuria and normal functional bladder capacity.

A melt tablet formulation offers benefits compared to regular tablets and nasal spray. Regular tablets are more difficult to swallow for some patients and require fluid intake for swallowing. Nasal spray absorption may be altered by seasonal allergies, upper respiratory infections or improper administration.

• Drug: desmopressin
• Drug: placebo

• Active Comparator: desmopressin
• Placebo Comparator: placebo

Inclusion Criteria:

• Children and adolescents (age 5-16 years) with diagnosed primary monosymptomatic nocturnal enuresis.
• A minimum of 3 wet nights per week in the 2-week screening period without treatment.

Exclusion Criteria:

• Presence or a history of organic urological disease, diurnal urinary incontinence, polydipsia, diabetes insipidus, ongoing urinary tract infection, clinically significant renal, hepatic, gastrointestinal, pulmonary, cardiovascular, endocrinological or neurological disease that would interfere with evaluation.
• Ongoing systemic antibiotic use, use of diuretics or any drugs affecting urinary concentration, or medical treatment for hyperactivity.
• Usage of any experimental drug or device during 30 days before study entry.