Which of the following drug is an osmotic diuretics?

Appeared in: UPPSC 2023

Explanation

Mannitol is the correct answer as it is the primary example of an osmotic diuretic.
Its mechanism involves increasing the osmolarity (solute concentration) of the fluid in the renal tubules (glomerular filtrate).
This high osmolarity draws water into the tubules and prevents it from being reabsorbed back into the body, leading to significant diuresis.
It is primarily used in acute settings to reduce intracranial pressure (cerebral edema) and intraocular pressure, not for managing general edema.

Option A: Spironolactone is a potassium-sparing diuretic, not an osmotic diuretic. It works by blocking the action of aldosterone.
Option C: Chlorothiazide is a thiazide diuretic. It works by inhibiting sodium and chloride reabsorption in the distal convoluted tubule.
Option D: Furosemide is a loop diuretic, the most potent class. It acts on the thick ascending limb of the loop of Henle.

Clinical Relevance

Nursing practice connection: Knowing Classification and mechanism of action of diuretics helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must administer IV Mannitol using a filter needle or in-line filter, as the solution can crystallize at low temperatures, which could cause a serious embolism if infused.
Key nursing monitoring for a patient on Mannitol includes strict intake and output, vital signs, serum electrolytes (especially sodium and potassium), and assessing for signs of dehydration or fluid overload (e.g., pulmonary congestion).
What if? If a patient receiving Mannitol for cerebral edema develops signs of heart failure or pulmonary edema (like crackles in the lungs), the infusion must be stopped immediately and the provider notified. Mannitol initially expands extracellular fluid volume, which can overwhelm a compromised heart.

How to Approach the Question

First, identify the key term in the question: 'osmotic diuretics'. This tells you the question is about drug classification.
Second, recall the definition and primary example of an osmotic diuretic. The main mechanism is altering osmotic pressure in the nephron.
Third, evaluate each option. Think about the class each drug belongs to: Spironolactone (potassium-sparing), Mannitol (osmotic), Chlorothiazide (thiazide), and Furosemide (loop).
Finally, select the option that matches the classification asked for in the question.

Concept Tested & Keywords

QJgcE4M5Fe_gbubHmgYzZd

E6 Pharmacology Nursing Lilley 11e Part 2 p. 150-152

E6 Pharmacology KD Tripathi Essentials 9e Part 2 pp. 264-266, 263-265

Practise the full UPPSC 2023

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