Kalium-sparing diuretics

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Kalium-canrenoate (Aldactone®) 125 mg in ampoule for i.v. application
chemical structure of spironolactone
chemical structure of amiloride
chemical structure of potassium canrenoate

Kalium-sparing diuretics act as aldosterone antagonists in the collecting duct and in the lower part of the distal tubule. It can be a direct antagonism – for example, spironolactone acts as a blocker of the mineralocorticoid receptor. In contrast, e.g. amiloride inhibits Na+ transport to ionic channels in the luminal membrane, thus reducing sodium resorption. This also reduces the loss of potassium in the urine, as resorption of Na+ from the collection ducts creates a negative electrical potential in their lumen, which facilitates the secretion of K+ and H+ into the urine.

Representatives[edit | edit source]

The main representatives include:

  • spironolactone, and its active metabolite, kalium-canrenoate
  • amiloride

Indications[edit | edit source]

Increased mineralocorticoid effect due to primary or secondary aldosteronism. Secondary aldosteronism is a consequence of heart failure , hepatic cirrhosis, nephrotic syndrome and the administration of thiazide and loop diuretics.

Side effects and toxicity[edit | edit source]

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