Neonatal Nurse Practitioner Practice Exam

What is the primary pharmacologic action of hydrochlorothiazide in neonates?

1. Affects chloride transport in the loop of Henle

2. Decreases calcium excretion

3. Inhibits sodium reabsorption in the distal nephron

4. Increases potassium reabsorption in the distal nephron

The correct answer is: Inhibits sodium reabsorption in the distal nephron

Hydrochlorothiazide primarily acts as a thiazide diuretic, and its main pharmacologic action is to inhibit sodium reabsorption in the distal nephron, specifically in the distal convoluted tubule. This inhibition leads to increased excretion of sodium and water, effectively promoting diuresis. This mechanism is particularly important in managing conditions that require fluid management, such as hypertension and edema. By preventing sodium from being reabsorbed back into the bloodstream, hydrochlorothiazide helps to lower blood volume, which in turn can help to reduce blood pressure. The actions of hydrochlorothiazide are evidenced by its role in altering electrolyte balance, which can also influence calcium levels. However, the primary effect remains its diuretic function, making its influence on sodium reabsorption in the distal nephron the most significant aspect to consider in the pharmacologic profile of this medication in neonates.