Amilorida

Amilorida (amiloride) is a potassium-sparing diuretic used to treat hypertension, edema associated with congestive heart failure, and certain disorders that cause abnormal sodium retention. It is a synthetic pyrazinoylguanidine that acts on the distal nephron of the kidney.

Amilorida’s primary mechanism is direct inhibition of epithelial sodium channels (ENaC) in the principal cells of the collecting duct and late distal tubule. By reducing sodium reabsorption at this site, it decreases water retention and reduces the electrochemical gradient for potassium secretion, thereby conserving potassium. Because it does not antagonize aldosterone receptors, its profile of hormonal side effects differs from that of mineralocorticoid receptor antagonists.

Clinically, amilorida is commonly prescribed alone or in combination with thiazide diuretics to limit thiazide-induced hypokalemia. It is effective in conditions such as hypertension, chronic heart failure with fluid overload, and genetic disorders like Liddle syndrome. It has also been investigated for off-label uses related to ENaC modulation.

Adverse effects include hyperkalemia, particularly in patients with renal impairment or those taking ACE inhibitors, ARBs, potassium supplements, or other potassium-sparing agents. Other possible reactions are gastrointestinal symptoms, dizziness, and rare allergic responses. Contraindications include severe hyperkalemia and significant renal dysfunction. Amilorida is eliminated primarily by the kidneys, and dosing considerations must account for renal function.