A neonate receives hydrochlorothiazide with spironolactone (Aldactazide) PO 1 mg/kg every 12 hours. The nurse should understand that the pharmacologic action

A neonate receives hydrochlorothiazide with spironolactone (Aldactazide) PO 1 mg/kg every 12 hours. The nurse should understand that the pharmacologic action

• A. Promotes potassium retention in distal nephron
• B. Inhibits sodium reabsorption in the distal nephron
• C. Inhibits water reabsorption in proximal tubule
• D. Blocks aldosterone receptors

Answer: (B)

This combination works by inhibiting sodium reabsorption in the distal nephron to promote diuresis while sparing potassium. The thiazide component blocks NaCl reabsorption in the distal convoluted tubule, leading to sodium and water loss. That increased delivery of sodium to the collecting ducts would normally drive potassium secretion, which can cause hypokalemia. The spironolactone component blocks aldosterone receptors in the collecting ducts, reducing sodium reabsorption and potassium loss, producing a potassium-sparing effect. Net result: fluid loss with preserved potassium, which is especially important in neonates. It’s not acting on the proximal tubule or primarily by blocking aldosterone receptors alone—the distal nephron site of action for overall sodium loss is what this combination emphasizes.

This combination works by inhibiting sodium reabsorption in the distal nephron to promote diuresis while sparing potassium. The thiazide component blocks NaCl reabsorption in the distal convoluted tubule, leading to sodium and water loss. That increased delivery of sodium to the collecting ducts would normally drive potassium secretion, which can cause hypokalemia. The spironolactone component blocks aldosterone receptors in the collecting ducts, reducing sodium reabsorption and potassium loss, producing a potassium-sparing effect. Net result: fluid loss with preserved potassium, which is especially important in neonates. It’s not acting on the proximal tubule or primarily by blocking aldosterone receptors alone—the distal nephron site of action for overall sodium loss is what this combination emphasizes.