VPT 311: General and Systemic Veterinary Pharmacology (2+1)

CLASSIFICATION OF DIURETICS

Based on their action on the kidneys diuretics are classified as

• Diuretics acting directly on the cells of the nephron
• Agents acting on the ascending loop of Henle – Ethacrynic acid, frusemide
• Agents acting on the early distal tubules – Thiazides like chlorthiazide
• Agents acting on the Collecting tubules and ducts – Triamterene, amiloride
• Diuretics modifying the contents of the filtrate
• Osmotic diuretics – Mannitol
• Carbonic anhydrase inhibitors – Acetazolamide
• Based on their mode of action diuretics are classified as
  • Osmotic diuretics – Glycerine, mannitol, urea, isosorbide
  • Inhibitors of carbonic anhydrase – Acetazolamide, dichlorphenamidine
  • Inhibitors of Na⁺-K⁺-2Cl^- symport (High ceiling loop diuretics) – Frusemide, Ethacrynic acid, Bumetanide
  • Inhibitors of Na⁺-Cl^- symport – Thiazide and thiazide like drugs
  • Potassium sparing diuretics 
    • Inhibitors of epithelial sodium channels – Triamterene, amiloride
    • Antagonists of aldosterone – Spironolactone
  • Xanthine diuretics – Theophylline
• It can also be classified as
  • Cardiac diuretics - Xanthines
  • Osmotic diuretics - Mannitol, Isosorbide, Urea
  • Natriuretics - Mercurials, Thiazides, Acetazolamide