Indapamide

Indapamide acts on the nephron, specifically at the proximal segment of the distal convoluted tubule where it inhibits the Na+/Cl- cotransporter, leading to reduced sodium reabsorption. As a result, sodium and water are retained in the lumen of the nephron for urinary excretion. The effects that follow include reduced plasma volume, reduced venous return, lower cardiac output, and ultimately decreased blood pressure.

Interestingly, it is likely that thiazide-like diuretics such as indapamide have additional blood pressure lowering mechanisms that are unrelated to diuresis. This is exemplified by the observation that the antihypertensive effects of thiazides are sustained 4-6 weeks after initiation of therapy, despite recovering plasma and extracellular fluid volumes.

Some studies have suggested that indapamide may decrease responsiveness to pressor agents while others have suggested it can decrease peripheral resistance. Although it is clear that diuresis contributes to the antihypertensive effects of indapamide, further studies are needed to investigate the medication’s ability to decrease peripheral vascular resistance and relax vascular smooth muscle.