What effect do diuretics have on the body?

Diuretics are medications primarily used to promote the excretion of water and electrolytes from the body through increased urine output. They act on the kidneys by inhibiting the reabsorption of sodium and water, leading to an increase in urine production. This mechanism effectively reduces fluid volume in the body, which can be beneficial in conditions such as hypertension, heart failure, and edema.

While diuretics can also contribute to the regulation of blood pressure, as indicated in choice C, their primary and most direct effect is indeed to increase the rate of urination. This action can help alleviate symptoms associated with fluid overload, such as swelling and high blood pressure, but the primary effect remains the increased output of urine. The other options—decreasing heart rate and increasing fluid retention—do not accurately represent the effects of diuretics, as they do the opposite of increasing fluid retention by promoting diuresis.