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aldosterone_antags

aldosterone antagonists

Introduction

  • Competitive antagonists of aldosterone (mineralocorticoids) acting on the receptor which is a soluble cytoplasmic protein thereby inhib. the synthesis of physiologically active transport proteins:
    • Na-K exchange in distal tubule & collecting duct → incr. Na excretion, decr. K excretion;
    • salivary glands
    • colon
  • may cause clinical hypoaldosteronism and potentially type IV renal tubular acidosis with hyperkalaemia and volume depletion

Spironolactone:

P/K:

  • 70% absorbed, signif. 1st pass metabolism & enterohep. circulation;
  • extensive plasma protein bound; Eliminated solely by metabolism to active (canrenone) & inactive (canrenoate) metabolites;

Adverse:

  • gynaecomastia, androgen-like effects; minor GIT effects; hyperkalaemia;

Interactions:

  • salicylates → decr. tub.secretion canrenone → decr. activity spironolactone;
  • high K intake or thiazides+renal impair. → hyperkalaemia;
aldosterone_antags.txt · Last modified: 2010/01/18 14:36 (external edit)