Effect of indomethacin on desmopressin resistant nocturnal polyuria and nocturnal enuresis.

PURPOSE: We evaluated the acute effect of indomethacin on renal water and solute handling in children with coexisting monosymptomatic nocturnal enuresis and desmopressin resistant nocturnal polyuria, and in healthy controls.

MATERIALS AND METHODS: A total of 23 subjects were recruited, consisting of 12 children with monosymptomatic nocturnal enuresis and nocturnal polyuria with partial or no response to desmopressin, and 11 age matched controls. Children completed a 48-hour inpatient study protocol consisting of fractional urine collections and blood samples. Sodium and water intake were standardized. During the second night a dose of 50 mg indomethacin was administered orally before bedtime. Diuresis, urine osmolalities, clearances and fractional excretions were calculated for sodium, potassium, urea, osmoles and solute-free water. Renin, angiotensin II, aldosterone and atrial natriuretic peptide were measured in plasma. Prostaglandin E(2) was measured in urine.

RESULTS: Indomethacin markedly decreased the nocturnal sodium, urea and osmotic excretion in children with enuresis and controls. The overall effect on nocturnal urine output was inconsistent in the group with enuresis. Subjects in whom nocturnal diuresis was decreased following administration of indomethacin remained dry.

CONCLUSIONS: Prostaglandin inhibition leads to antidiuresis, reducing the amount of sodium, urea and osmotic excretion in children with monosymptomatic nocturnal enuresis and desmopressin resistant nocturnal polyuria. The sodium regulating hormones do not seem to mediate these processes. The overall effect in desmopressin nonresponders with nocturnal polyuria is variable. The extent to which indomethacin can be applied in the treatment of enuresis needs further evaluation.