Hypocalciuric effects of hydrochlorothiazide in the rat during NaHCO3, NaCl and NH4Cl loading.

Hydrochlorothiazide (HCTZ) and NaHCO3 each lower urinary calcium excretion, while NaCl and NH4Cl each increase urinary calcium. This study examines the ability of HCTZ to lower urinary calcium during NaHCO3, NaCl and NH4Cl loading in the rat. We show that HCTZ lowers urinary calcium in rats treated with NaHCO3, NaCl and NH4Cl. We demonstrate that urinary calcium excretion is depressed to a greater degree by administering NaHCO3 and HCTZ in combination than by administering these agents separately.