Triamterene is a potassium-sparing diuretic used in combination with thiazide diuretics for the treatment of hypertension and edema. Triamterene directly blocks the epithelial sodium channel (ENaC) on the lumen side of the kidney collecting tubule. Other diuretics cause a decrease in the sodium concentration of the forming urine due to the entry of sodium into the cell via the ENaC, and the concomitant exit of potassium from the principal cell into the forming urine. Blocking ENaC prevents this from happening. Amiloride works in the same way. Sodium channel blockers directly inhibit the entry of sodium into the sodium channels. Triamterene is commonly prepared in combination with hydrochlorothiazide for treatment of hypertension and edema. This combination is in a class of medications called diuretics or 'water pills', and causes the kidneys to get rid of the body's unneeded water and sodium through the urine.
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