Which of the following drugs is an osmotic diuretic?

Correct option is A

Ans. (a) Mannitol
Explanation:
✅ Mannitol is an osmotic diuretic that works by increasing osmolarity in the renal tubules, drawing water out and increasing urine output.
Mechanism of Action of Mannitol (Osmotic Diuretic):
· Mannitol is filtered in the glomerulus but not reabsorbed in the nephron.
· It creates an osmotic gradient, pulling water into the renal tubules, leading to increased urine output.
· Does not interfere with sodium reabsorption, unlike other diuretics.
Uses of Mannitol:
✅ Cerebral Edema & Increased Intracranial Pressure (ICP) → Reduces brain swelling. ✅ Acute Glaucoma → Lowers intraocular pressure (IOP). ✅ Acute Kidney Injury (AKI) → Prevents tubular damage.
Why are the other options incorrect?
1. Furosemide → (Incorrect Choice)❌
· Loop diuretic, acts on the Na⁺-K⁺-2Cl⁻ symporter in the Loop of Henle.
· Used for pulmonary edema, hypertension, and heart failure.
2. Spironolactone → (Incorrect Choice)❌
· Potassium-sparing diuretic, blocks aldosterone receptors in the distal tubule.
· Used for heart failure, resistant hypertension, and hyperaldosteronism.
3. Chlorothiazide → (Incorrect Choice)❌
· Thiazide diuretic, acts on the distal tubule to inhibit Na⁺/Cl⁻ reabsorption.
· Used for hypertension and mild edema.