Spironolactone is an example of?

Appeared in: NORCET 3 - 2022 (Shift-1)

Explanation

Spironolactone is correctly classified as a potassium-sparing diuretic.
It functions as a competitive antagonist of aldosterone, a hormone involved in sodium and water balance.
By blocking aldosterone receptors in the distal nephron (collecting ducts and distal convoluted tubules), it promotes the excretion of sodium and water while preventing the excretion of potassium.
This potassium-retaining effect is the defining characteristic of this diuretic class and contrasts with loop and thiazide diuretics, which cause potassium loss.

Option A: Loop diuretics, such as furosemide, are incorrect. They are potent diuretics that act on the thick ascending limb of the Loop of Henle and are known for causing significant potassium loss (hypokalemia).
Option B: Thiazide diuretics, like hydrochlorothiazide, are incorrect. They act on the distal convoluted tubule and also cause potassium loss, although typically less than loop diuretics.
Option D: Osmotic diuretics, such as mannitol, are incorrect. They work by increasing the osmotic pressure of the glomerular filtrate, which pulls water into the renal tubules. Their primary use is to reduce intracranial or intraocular pressure, not for managing edema or hypertension.

Visual 1: Diagram - An illustration of the nephron showing the specific sites of action for loop, thiazide, potassium-sparing, and osmotic diuretics. This helps visualize why their effects on electrolytes differ.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological classification of diuretics as background academic context rather than a clinical decision trigger.
Monitoring for hyperkalemia (serum K+ greater than 5.0 mEq/L) is a critical nursing responsibility for patients on spironolactone, especially those with renal impairment or taking ACE inhibitors.
Patient education should include recognizing signs of hyperkalemia (muscle weakness, fatigue, palpitations) and avoiding high-potassium foods and salt substitutes containing potassium chloride.
Spironolactone is frequently used in managing heart failure, cirrhosis-related ascites, and hyperaldosteronism.

How to Approach the Question

This is a factual recall question common in pharmacology.
First, identify the drug named in the question stem: 'Spironolactone'.
Next, access your knowledge of major drug classifications, specifically diuretics.
Recall the four main types of diuretics: loop, thiazide, potassium-sparing, and osmotic.
Categorize spironolactone into its correct class. A key memory aid is that spironolactone 'spares' or saves potassium.
Review the options provided and select the one that matches your classification.

Concept Tested & Keywords

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Practise the full NORCET 3 - 2022 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.