Potassium-sparing diuretic
- Potassium-sparing diuretic
Potassium-sparing diuretics are diuretic drugs that do not promote the secretion of potassium into the urine. They are used as adjunctive therapy, together with other drugs, in the treatment of hypertension and management of congestive heart failure.
Indications
Potassium-sparing diuretics are generally used in combination with other diuretic drugs (e.g. loop diuretics) that would otherwise tend to lower the potassium levels to potentially dangerous low levels (hypokalemia). The combination therefore helps maintain a normal reference range for potassium.
Adverse effects
On their own this group of drugs may raise potassium levels beyond the normal range, termed hyperkalemia, which risks potentially fatal arrhythmias.
Mechanism of action
The potassium-sparing diuretics are competitive antagonists that compete with aldosterone for intracellular cytoplasmic receptor sites. This prevents the production of proteins that are normally synthesized in reaction to aldosterone. These mediator proteins are not produced, and so stimulation of sodium-potassium exchange sites in the collection tubule does not occur. This prevents sodium re-absorption and potassium and hydrogen ion secretion. [Pharmacology. 2nd ed. Harvey, Champe.]
Chemical structure
Potassium-sparing diuretics do not share any obvious chemical similarities, except for the steroid-structure of the aldosterone antagonists. Those in clinical use include:
* Amiloride
* Triamterene
* Aldosterone antagonists:
** Spironolactone
** Eplerenone
ee also
* C03D Potassium-sparing agents
References
* Block JH, Beale JM. "Organic Medicinal and Pharmaceutical Chemistry" 11th edition. Lippincott Williams & Wilkins. 2004.
External links
*
Wikimedia Foundation.
2010.
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