Potassium-sparing diuretic
Potassium-sparing diuretics are diuretic drugs that do not promote the secretion of potassium into the urine.[1]
They are used as adjunctive therapy, together with other drugs, in the treatment of hypertension and management of congestive heart failure.
Contents
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, or by directly blocking sodium channels (specifically ENaC by amiloride (ENaC is Epithelial Sodium Channel)). The former 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.[2]
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:
See also
References
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de:Kaliumsparende Diuretika es:Diurético ahorrador de potasio eu:Diuretiko potasio aurreztaile he:משתנים אוגרי אשלגן nl:Kaliumsparend diureticum
pt:Diurético poupador do potássio- ↑ diuretic at Dorland's Medical Dictionary
- ↑ Pharmacology. 2nd ed. Harvey, Champe.
