A 4-year-old boy (weight 12 kg, BSA 0.8 m2) has had slow onset of DI symptoms. He did not have a prompt increase in osmolality to the water deprivation test. The patient is being treated for underlying conditions. He is on a diet that maximizes calories while limiting salt intake and currently takes hydrochlorothiazide. He is currently uncontrolled. Which is the most appropriate adjunctive treatment?
a. Desmopressin.
b. Indomethacin.
c. Chlorothiazide.
d. Amiloride.