What is the mechanism of action of thiazide diuretics?

Thiazide diuretics primarily exert their antihypertensive effect by inhibiting sodium and chloride reabsorption in the distal convoluted tubule of the nephron in the kidneys. By blocking the sodium-chloride symporter in this part of the nephron, thiazide diuretics lead to increased excretion of sodium and chloride into the urine. This diuretic effect reduces the overall fluid volume in the body, resulting in decreased blood volume and consequently lower blood pressure.

This mechanism is important not only for managing hypertension but also for treating conditions like edema. By effectively reducing fluid overload, thiazide diuretics can promote a significant decrease in blood pressure along with a favorable influence on cardiac workload.

The other mechanisms mentioned do not pertain to the action of thiazide diuretics. For example, blocking calcium channels is more characteristic of calcium channel blockers, stimulating renin release is associated with other classes of antihypertensives, and inhibiting vasopressin action relates to different types of diuretics that affect water reabsorption rather than the regulation of electrolytes.