Visual Summary

Loop Diuretics and Aldosterone Antagonists

Module 4 — Introduction to Medical Pharmacology

Two Classes, Two Different Roles

Symptom Control Only

Loop Diuretics

  • Blocks the sodium-potassium-2-chloride cotransporter in the thick ascending limb
  • Rapid relief of congestion
  • Wastes potassium, magnesium, calcium
  • Does not improve survival

Survival Pillar

Aldosterone Antagonists

  • Blocks the mineralocorticoid receptor
  • Mild diuretic effect only
  • Reduces cardiac fibrosis directly
  • Reduces mortality

Spironolactone Versus Eplerenone

FeatureSpironolactoneEplerenone
Receptor selectivityAlso binds androgen and progesterone receptorsHighly selective for the mineralocorticoid receptor
Endocrine side effectsGynecomastia, breast tendernessMinimal
Typical useDefault first choiceSubstituted when spironolactone causes endocrine effects

Potassium Balance With Combined Therapy

Loop diuretics lower potassium RAAS blockers and aldosterone antagonists raise potassium Regular monitoring required with combined therapy