NEOTRI

Xipamide is an anti-hypertensive diuretic which can be characterised pharmacologically neither as a thiazide nor as a specific loop diuretic. Although structurally similar to chlorthalidone, it has a markedly different pharmacological profile with its main diuretic effect exerted at the distal section of the nephron.

Triamterene is a potassium-sparing agent. Triamterene inhibits the reabsorption of sodium ions in exchange for potassium and hydrogen ions at that segment of the distal tubule under the control of adrenal mineralocorticoids (especially aldosterone). The fraction of filtered sodium reaching this distal tubular exchange site is relatively small, and the amount which is exchanged depends on the level of mineralocorticoid activity. Thus, the degree of natriuresis and diuresis produced by inhibition of the exchange mechanism is necessarily limited.