A Clinical Study of the Effects of Hydrochlorothiazide on the Renal Excretion of Electrolytes and Free Water

HYDROCHLOROTHIAZIDE (6-chloro-7-sulfamyl-3,4,dihydro-l,2,4, benzothiadiazine-1,1,-dioxide) is the 3,4,dihydro derivative of chlorothiazide wherein the 3,4 double bond is saturated by two hydrogen atoms (Fig. 1). In animals the compound has been shown to produce an increased renal excretion of sodium, potassium and chloride.1 However, in its effects on electrolyte excretion, dihydrochlorothiazide appeared to be five times more potent than chlorothiazide when given intravenously to dogs and some ten times more potent than chlorothiazide when given orally.Previous studies have characterized the effect of chlorothiazide on electrolyte transport in normal subjects and in patients with heart failure, cirrhosis and nephrosis.2 , 3 The intravenous administration of . . .