Spironolactone

Spironolactone is a potassium-sparing diuretic that blocks mineralocorticoid receptors, reducing aldosterone’s effects on sodium retention and potassium excretion.

Mineralocorticoid receptor: A nuclear receptor activated mainly by aldosterone that regulates sodium and potassium balance in epithelial tissues. Spironolactone binds this receptor and prevents aldosterone from activating it.
Heart failure with reduced ejection fraction: Heart failure in which the left ventricle ejects a reduced proportion of its blood with each contraction. Spironolactone can reduce death and hospitalization in selected patients with this condition.
Eplerenone: A selective mineralocorticoid-receptor antagonist used for hypertension and certain forms of heart failure. It has fewer sex-h hormone-related effects but is generally less potent and often more costly.
Nephron: The kidney’s microscopic functional unit, which filters blood and adjusts the composition of urine. Spironolactone changes electrolyte handling in the nephron’s late segments.
RALES: A landmark randomized trial testing low-dose spironolactone in severe systolic heart failure. It established a substantial survival benefit in selected patients receiving standard therapy.
Aldosterone: A steroid hormone that promotes sodium retention and potassium excretion, helping regulate blood volume and pressure. Blocking aldosterone’s effects is spironolactone’s principal mechanism.
Primary aldosteronism: Excess aldosterone production from one or both adrenal glands, causing hypertension and often low blood potassium. Spironolactone blocks aldosterone’s effects when surgery is unsuitable or disease is bilateral.
Amiloride: A potassium-sparing diuretic that directly blocks epithelial sodium channels in the kidney. It conserves potassium through channel blockade rather than aldosterone-receptor antagonism.
Potassium: An essential electrolyte involved in cellular electrical activity, muscle contraction, and heart rhythm. Spironolactone reduces potassium excretion, so blood levels require attention.
TOPCAT: A randomized trial evaluating spironolactone in patients with heart failure and preserved ejection fraction. Its mixed findings exposed the difficulty of establishing benefit in this heart-failure population.

Linked from 8 pages