the renal excretion of salt and water, thereby reducing extracellular fluid volume and cardiac output, but they also reduce intracellular sodium and calcium levels, leading to vasorelaxation and a reduction in peripheral vascular resistance with long-term use. Thiazide-type diuretics are effective antihypertensive agents in patients with normal or modestly impaired renal function as long as their dietary sodium intake does not exceed their renal sodium excretion