Kalium-sparing diuretics

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]

Hyperkalemia can also reach life-threatening levels. The risk of this complication is intensified if the kidneys are affected or with the simultaneous administration of drugs (beta-blockers, nonsteroidal antirheumatics or ACE inhibitors).
Hyperchloremic metabolic acidosis can be provoked when inhibiting secretion H+ under simultaneous K+ secretion..
Gynecomastia – spironolactone.

Links[edit | edit source]

Source[edit | edit source]

MARTÍNKOVÁ, Jiřina – MIČUDA, Stanislav – CERMANOVÁ, Jolana. Vybrané kapitoly z klinické farmakologie pro bakalářské studium : Kardiovaskulární systém [online]. ©2000. [cit. 2010-07-02]. <https://www.lfhk.cuni.cz/farmakol/predn/bak/kapitoly/prednasky/kardio-bak.ppt/>.