triamtereen

Triamterene, sometimes spelled triamtereen in some languages, is a potassium-sparing diuretic used in the management of edema and hypertension. It acts on the distal nephron, primarily blocking epithelial sodium channels in the collecting ducts. By inhibiting sodium reabsorption at this site, it increases sodium (and water) excretion while reducing potassium loss in the urine, hence its potassium-sparing property.

In clinical practice, triamterene is used to treat edema associated with heart failure, liver cirrhosis, or nephrotic syndrome and to help control blood pressure. It is frequently prescribed in combination with a thiazide or thiazide-like diuretic to offset potassium loss caused by those agents and to enhance antihypertensive effects. Fixed-dose combinations with hydrochlorothiazide are common.

Pharmacologically, triamterene is oral and generally begins to exert effects within hours, with a duration that supports daily dosing in most regimens. It is mainly excreted in the urine, with active metabolites contributing to its activity. The drug’s effect is influenced by renal function and hydration status.

Common adverse effects include hyperkalemia, particularly in patients with renal impairment, those taking other potassium-sparing drugs, or those using ACE inhibitors or ARBs. Other possible effects include nausea, dizziness, headache, and, less commonly, kidney stones due to crystal formation in urine. Use requires caution in pregnancy and lactation, and it should be avoided in patients with anuria or significant kidney dysfunction.

Drug interactions center on competing or additive effects on potassium balance and renal function. Triamterene remains a widely used component of diuretic regimens, especially when potassium conservation is desired.