Triamterene (trade name Dyrenium) is a potassium-sparing diuretic used in combination with thiazide diuretics for the treatment of hypertension and edema.

Triamterene (trade name Dyrenium) is a potassium-sparing diuretic used in combination with thiazide diuretics for the treatment of hypertension and edema. This medication is best avoided in patients with chronic kidney disease due to the possibility of hyperkalemia. People using this drug should use salt substitute very cautiously.

Mode of action
Triamterene directly blocks the epithelial sodium channel (ENaC) on the lumen side of the kidney collecting tubule. Other diuretics cause an increase in the sodium concentrations in the forming urine causing more sodium to enter through ENaC, chasing more potassium out of the principal cell and into the forming urine. Blocking ENaC prevents this from happening. Amiloride works in the same way.

Side effects
Common side effects may include a depletion of sodium, folic acid and calcium, nausea, vomiting, diarrhea, headache, dizziness, fatigue, and dry mouth. Serious side effects may include heart palpitations, tingling/numbness, fever, chills, sore throat, rash, and back pain. Triamterene can also cause kidney stones through direct crystallization or by seeding calcium oxalate stones.