Potassium-Sparing Diuretics NCLEX Questions Pharmacology (NCLEX EXAM 2022)

1. The physician prescribes the patient a potassium-sparing diuretic. Which statement below best describes how this medication works to cause diuresis? A. These medications work to inhibit the sodium-chloride cotransporter in the early part of the distal convoluted tubule. B. These medications work to inhibit the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle. C. These medications work to inhibit the sodium and potassium exchange within the sodium channels in the distal tubule and collecting duct. D. These medications work to inhibit the sodium channels within the proximal convoluted tubule by decreasing sodium reabsorption. The answer is C. Potassium-sparing diuretics work to inhibit the sodium and potassium exchange within the sodium channels in the distal tubule and collecting duct. 2. Which potassium-sparing diuretics are known to antagonize aldosterone in order to cause diuresis? Select all that apply: A. Triamterene B. Spironolactone C. Amiloride D. Eplerenone The answers are B and D. Spironolactone and Eplerenone are types of potassium-sparing diuretics that are known as the aldosterone antagnoists or aldosterone receptor blockers. These medications work against aldosterone (hence the name aldosterone “antagnoists”). Aldosterone normally works to influence epithelial sodium channels and the sodium-potassium pumps in the distal tubule and collecting duct by increasing this number. This leads to the reabsorption of sodium into the bloodstream from the filtrate and secretion of potassium into the filtrate from the blood. However, when this is inhibited (due to these medications) sodium is NOT reabsorbed back into the blood and potassium is NOT secreted into the filtrate but stays in the blood (hence this can lead to HYPERkalemia). Triamterene and Amiloride are potassium-sparing diuretics, BUT they work to inhibit the epithelial sodium channels, which causes the same affects as the aldosterone antagonists but in a different way.