Furosemide (Lasix) is a/an?

Appeared in: UPRVUNL - 2021

Explanation

Furosemide is the prototypical loop diuretic, one of the most potent classes of diuretics available.
It acts on the thick ascending limb of the loop of Henle in the kidneys.
Its mechanism involves inhibiting the Na-K-2Cl cotransporter, which prevents the reabsorption of sodium and chloride, leading to significant water excretion (diuresis).
This potent effect makes it a primary choice for treating severe edema associated with heart failure, cirrhosis, and renal failure.

Option A: This is incorrect. Osmotic diuretics, like Mannitol, work by creating osmotic pressure in the nephron, which draws water into the urine. They are primarily used to reduce intracranial or intraocular pressure, not for general edema.
Option C: This is incorrect. Potassium-sparing diuretics, such as Spironolactone, act on the collecting ducts to promote sodium and water excretion while retaining potassium. They are much weaker diuretics than furosemide.
Option D: This is incorrect. Thiazide diuretics, like Hydrochlorothiazide, act on the distal convoluted tubule. They are less potent than loop diuretics and are a common first-line treatment for hypertension.

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.
A critical nursing responsibility when administering furosemide is monitoring for signs of hypokalemia (low potassium), such as muscle cramps, weakness, and cardiac dysrhythmias, as it is a common and dangerous side effect.
Nurses must educate patients to take furosemide in the morning to prevent nocturia (frequent urination at night), which can disrupt sleep and increase the risk of falls.
When administering furosemide intravenously, it must be given slowly (e.g., not exceeding 20 mg/min) to prevent ototoxicity (hearing damage), a potential adverse effect with rapid infusion.

How to Approach the Question

First, identify the drug in the question: Furosemide, with its brand name Lasix provided as a clue.
This is a factual recall question that requires knowledge of pharmacology. Access your memory about diuretic classifications.
Recall the major classes of diuretics: Loop, Thiazide, Potassium-sparing, and Osmotic.
Place Furosemide into its correct category. It is the most common example of a loop diuretic.
Review the options provided and select 'Loop diuretic'.
Mentally confirm why the other options are incorrect by recalling examples for each (e.g., Mannitol for osmotic, Spironolactone for potassium-sparing, HCTZ for thiazide).

Concept Tested & Keywords

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E6 Pharmacology Katzung 16e p. 423-425

E6 Pharmacology Nursing Lilley 11e Part 2 pp. 149-151, 148-150

Practise the full UPRVUNL - 2021

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