Balancing diuretic therapy in heart failure: loop diuretics, thiazides, and aldosterone antagonists.

In heart failure, sodium is retained by the kidneys despite increases in extracellular volume. There is activation of renin secretion, which culminates in the production of angiotensin II, causing vasoconstriction and aldosterone secretion. These synergistically produce an increase in tubular reabsorption of sodium and water. Diuretics are the mainstay of symptomatic treatment to remove excess extracellular fluid in heart failure. Diuretics that affect the ascending loop of Henle are most commonly used. Thiazide diuretics promote a much greater natriuretic effect when combined with a loop diuretic in patients with refractory edema. Recently, spironolactone, an aldosterone receptor blocking agent, has been recommended to attenuate some of the neurohormonal effects of heart failure. Regardless of the diuretic, patients need to be counseled on the importance of avoiding sodium in their diet