The efficacy and safety of furosemide and a combination of spironolactone and hydrochlorothiazide in congestive heart failure.

The therapeutic and biochemical effects of two commonly employed diuretic preparations were compared in a double-blind fashion in 32 patients with congestive heart failure. At the doses employed, furosemide and a fixed combination of spironolactone and hydrochlothiazide maintained control of the clinical manifestations of congestive heart failure to about the same degree. However, significant biochemical changes in the renin-aldosterone system were found in patients receiving the spironolactone/thiazide combination therapy. A significant increase in plasma renin activity and a significantly greater increase in aldosterone excretion were found in the spironolactone/thiazide group compared to the furosemide group. No significant differences were observed in serum potassium levels or 24-hour potassium excretion rates in patients treated with the two diuretic preparations.