Decreased nocturnal urinary antidiuretic hormone excretion in enuresis is increased by imipramine.

OBJECTIVE: To assess the role of integrated nocturnal antidiuretic hormone (ADH) secretion in children with enuresis, and possible modifications induced by treatment with imipramine. PATIENTS AND METHODS: The morning plasma ADH and nocturnal urinary ADH integrated concentrations were measured in 18 consecutive enuretic children (patients) and 21 age- and sex-matched controls admitted for minor treatment. Diurnal and nocturnal urine production, and plasma and urinary osmolality were also determined; lumbosacral radiography and uroflowmetry were undertaken in the patients. The assessments were repeated after 14 days of treatment with imipramine hydrochloride (orally, 20 mg/night). RESULTS: Half the patients had occult spinal malformations but the uroflowmetry results were all within the normal range. The median (95% confidence interval, CI) urinary ADH integrated concentrations were markedly lower in patients, at 29.7 (22.1-37.3) vs 63.0 (35.1-90.8) pg/mL/h (P = 0.03) than in controls. Plasma ADH levels were significantly increased by imipramine (0.64 to 1.47 pg/mL, 95% CI, 0.40-0.89 vs -0.26-3.2; P < 0.001), as were nocturnal urinary ADH integrated concentrations, at 29.7 (22.1-37.3) vs 59.0 (37.3-80.6) pg/mL/h (P < 0.001), and morning plasma osmolality decreased, from 298.5 (294.5-302.5) to 294.9 (292.4-297.3) mosmol/kg (P = 0.003), as was the 24-h fluid intake, from 983 (721-1245) to 666 (435-897) mL (P = 0.004). CONCLUSIONS: We conclude that enuretic children have a lower nocturnal ADH excretion; imipramine restores nocturnal ADH excretion, increases morning plasma ADH levels, and causes consistent changes in other biochemical variables.

[Effect of imipramine hydrochloride on urinary function and serum parameters in enuretic children: preliminary study]. / Action de l'Hydrochloride d'Imipramine sur la fonction urinaire et sur les paramètres sériques chez les enfants énurétiques: étude préliminaire.

We still do not know whether Imipramine works exactly as an antidiuretic. The aim of this study was to investigate any existing urinary or serum factor differences between 9 children with primary nocturnal enuresis and six age and sex matched controls and to see if therapy with Imipramine could modify these parameters. All subjects underwent an evaluation of daily and nightly urinary volume, daily fluid intake, morning plasma and urine osmolality, plasma aldosterone, electrolytes, blood urea nitrogen and plasma glucose. The results, using a one-way ANOVA, would suggest the following: 1) enuretic children have a higher 24 urinary volume with a reduced osmolality compared to controls; 2) Aldosterone does not seem to be involved in the pathogenesis of enuresis; 3) Imipramine HCL therapy does reduce the volume of urine lost in diapers, and its efficiency can be documented objectively; 4) Imipramine HCL's mechanism appears to be related to an increased renal water resorption.