
investigations into the thiazide-induced antidiuresis in
patients with diabetes insipidus
plasma sodium, osmolality and serum
chloride, together with creatinine clear-
ance, were studied before and during
thiazide treatment of 7 patients with
diabetes insipidus.
the diuresis was reduced by 28-39%.
the urine osmolality was increased by
7-128%.  an average decrease in plasma
sodium of 4 meq/i, in plasma osmolality
of 21 mosm/kg, and in serum chloride of
8 meq/i was observed.  only in one pa-
tient was the creatinine clearance re-
duced significantly.  the thirst-feeling was
reduced even from the first day of treat-
ment.  the diuresis was not minimal until
the third to fourth day.  if the diuresis was
corrected for the extra electrolyte ex-
cretion initiated by the thiazide, the
antidiuresis was found to be operating to
the full extent even on the first day of
treatment.
it is concluded that the antidiuresis is
mainly secondary to the natriuresis and to
a certain degree due to a decreased thirst-
feeling; but there seems also to be a direct
renal action, involving at least a reduc-
tion of the glomerular filtration rate.  a
pronounced antidiuresis was found by a
water deprivation test after thiazide
treatment in one patient.
