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
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]
Related articles[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/>.