Chlorothiazide* (6-chloro-7-sulfamyl-1,2,4-benzothiadiazine-1,1-dioxide) has been shown to be a potent diuretic substance when given either orally or parenterally.1-4 Its major effect as a diuretic consists of increasing renal excretion of sodium and chloride, presumably by a decrease in tubular reabsorption, with a secondary loss of water. In vitro chlorothiazide has mild carbonic-anhydrase-inhibition action (approximately 10 times that of sulfanilamide and 1/25 that of acetazolamide [Diamox] ); however, this effect has not been implicated as playing a significant role in diuresis in vivo.1,3 This drug was used in the present study to evaluate its possible mode of action and its effectiveness as a diuretic.
Methods and Materials
This study was divided into two parts: (1) changes in cardiac and renal hemodynamics and in water and electrolyte excretion following intravenous chlorothiazide, and (2) effectiveness of oral chlorothiazide in patients with edema, as evidenced by diuresis and by the changes in electrolyte excretion.