Intravenously Administered Chlorothiazide in Diagnostic Evaluation of Hypertensive Disease

Urinary electrolyte excretion in response to rapid intravenous administration of chlorothiazide (500 mg) was unpredictable in primary aldosteronism. Only 43% of patients with primary aldosteronism demonstrated an exaggerated or excessive kaliuretic response, whereas none of the normal subjects and patients with benign essential hypertension responded with increased potassium ion excretion. A significant increase in plasma renin activity (PRA) after intravenous administration of chlorothiazide was observed in only seven of 15 patients previously documented to have a "normally responsive" PRA following dietary sodium restriction plus diuretics. In contrast to previous reports, our data would suggest that the electrolyte excretion after acute intravenous infusion of chlorothiazide lacks the diagnostic specificity or sensitivity to be used as a screening procedure for the detection of primary aldosteronism and, in addition, that this maneuver does not consistently stimulate an increase in PRA.