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Overview of the Different Diuretics

The following article provides an overview of the different diuretics, their renal targets, as well as the effects associated with these diuretics.

Carbonic anhydrase inhibitors

Active substances: Acetazolamide, dorzolamide, brinzolamide

Renal target: Proximal tubule inhibition of carbonic anhydrase

Effect on serum electrolytes:

  • Decreased sodium and bicarbonate, increased protons
  • Possible hypokalemia, hyperglycemia

Drainage Effectiveness: Not commonly used as a diuretic due to the loss of electrolytes and bicarbonate

Loop diuretics

Active substances: Furosemide, bumetanide, piretanide, torasemide

Renal target: Thick ascending limb of the Henle loop, luminal Na-K-Cl-cotransporter, decreased reabsorption

Effect on serum electrolytes: Decreased Na, K, Cl, Ca, Mg, decreased reabsorption of H2O in the collecting duct system (due to the changed osmotic gradient), possible hyperglycemia, hyperuricemia.

Drainage Effectiveness:

Most effective diuretic (20–30% of the glomerular filtrates)

Thiazide diuretics and thiazide analogs

Active substances: Hydrochlorothiazide, chlorthalidone, mefruside, xipamide

Renal target: Early disinhibition of the Na-Cl cotransporter, resulting in decreased NaCl reabsorption

Effect on serum electrolytes:

  • Decreased Na, Cl, Mg, decreased K (as a lot of Na can be exchanged for K in the late distal tubule)
  • Increased Ca
  • Possibly hyperglycemia, hyperuricemia

Drainage Effectiveness: Moderate effects (10–15% of the glomerular filtrates)

Potassium-sparing diuretics

Active substances: Amiloride, triamterene

Renal target: 

  • Late distal tubule and collecting duct system
  • Inhibition of sodium channels

Effect on the serum electrolytes: Decreased Na, increased K

Drainage Effectiveness: Low effects (2–4% of the glomerular filtrates)

Aldosterone antagonists

Active substances: Spironolactone, potassium canrenoate, eplerenone

Renal target:

  • Late distal tubule and collecting duct system
  • Competitive inhibition at the cytosolic mineralocorticoid receptor

Effect on serum electrolytes: Decreased Na, increased K

Drainage Effectiveness: Low effects (2–3% of the glomerular filtrates)

Osmotic diuretics

Active substances: Mannitol, sorbitol

Renal target:

  • Nonspecific osmodiuretic effect in the lumen of the entire tubule
  • Filtrated in the glomerulus and are not reabsorbed

Effect on the serum electrolytes: Possible increase in Na

Drainage Effectiveness: Low effects (2–3% of the glomerular filtrates)

Methylxanthines

Active substances: Theophylline, theobromine, caffeine

Renal target: Antagonist at the adenosine receptor (subtype A1), possible inhibition of the basolateral Na-HCO3– cotransporter in the proximal tubule

Effect on serum electrolytes: Decreased Na and HCO3, increased H

Drainage Effectiveness: Little usefulness as a diuretic due to adverse effects

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