Congenital nephrogenic diabetes insipidus-vasopressin and prostaglandins in response to treatment with hydrochlorothiazide and indomethacin.

In four boys with congenital nephrogenic diabetes insipidus, plasma arginine-vasopressin (AVP) and urinary excretion of prostaglandins were studied in response to treatment with hydrochlorothiazide and indomethacin. An abnormal relationship between AVP and urine osmolality was demonstrated in all patients. In the first patient, treatment with indomethacin (3 mg/kg per day) resulted in a drop of the insulin and paraminohippurate clearances. In the other three patients urinary excretion of PGE2 was raised, and fell during treatment with hydrochlorothiazide (2 mg/kg per day) and indomethacin (2 mg/kg per day). Urine flow, free water clearance and osmolar clearance decreased during treatment. A combination of both drugs is more effective than hydrochlorothiazide alone and the effect appears to be additive.