NCIt definition : A pteridine derivative with potassium-sparing diuretic property. Triamterene blocks
the sodium-potassium exchange pump (Na-K-ATPase) in the luminal membrane of principal
cells in the late distal tubule, cortical collecting tubule and collecting duct in
the kidney. This reversible inhibition of the electrogenic sodium transport decreases
the lumen-negative transepithelial potential difference and thus reduces the driving
force for K movement into the tubular lumen resulting in the inhibition of sodium
reabsorption in exchange for K and H .;