Which diuretic may contribute to hyponatremia in a patient?

Hydrochlorothiazide is a thiazide diuretic that can contribute to hyponatremia, which is a lower-than-normal level of sodium in the blood. Thiazide diuretics work on the distal convoluted tubule of the kidney to inhibit sodium reabsorption, leading to increased excretion of sodium and water. This mechanism can lead to dilutional hyponatremia, especially in cases where there is excessive water intake or when sodium levels already are low.

In clinical practice, hyponatremia can occur because the excess loss of sodium can outpace the body's ability to compensate for fluid loss, particularly in patients who may also have conditions that predispose them to fluid retention or excessive fluid intake. Monitoring electrolytes, especially sodium, is important for patients on hydrochlorothiazide, particularly over prolonged use or in populations at risk for electrolyte imbalances, such as the elderly or those with heart failure. The other options listed do not carry the same risk of inducing hyponatremia as hydrochlorothiazide does.