Nephrogenic diabetes insipidus (NDI) is characterised by the inability of the kidney to concentrate urine in response to
arginine vasopressin. The consequences are severe
polyuria and
polydipsia, often associated with hypertonic
dehydration. Intracerebral calcification,
seizures, psychosomatic retardation,
hydronephrosis, and hydroureters are its sequelae. In this study, four children with NDI were treated with 3 mg/kg/day
hydrochlorothiazide and 0.3 mg/kg/day
amiloride orally three times a day for up to five years. While undergoing treatment, none of the patients had signs of
dehydration or
electrolyte imbalance, all showed normal body growth, and there was no evidence of cerebral calcification or
seizures. All but one had normal psychomotor development and normal sonography of the urinary tract. However, normal fluid balance was not attainable (fluid intake, 3.8-7.7 l/m2/day; urine output, 2.2-7.4 l/m2/day). The treatment was well tolerated and no side effects could be detected. Prolonged treatment with
hydrochlorothiazide/
amiloride appears to be more effective and better tolerated than just
hydrochlorothiazide. Its efficacy appears to be similar to that of
hydrochlorothiazide/
indomethacin but without their severe side effects.