Diuretics & Electrolyte Drugs Practice Exam (Questions 1–150 And Rationales) 2025/2026

Diuretics & Electrolyte Drugs Practice
Exam (Questions 1–150 And
Rationales)
2025/2026




1. Which class of diuretics acts on the ascending limb of the loop of
Henle?
A. Thiazides
B. Potassium-sparing diuretics
C. Osmotic diuretics
D. Loop diuretics
Answer: D. Loop diuretics
Rationale: Loop diuretics inhibit sodium and chloride
reabsorption in the ascending limb of the loop of Henle.
2. Which drug is a loop diuretic?
A. Hydrochlorothiazide
B. Spironolactone
C. Furosemide
D. Amiloride
Answer: C. Furosemide
Rationale: Furosemide is a potent loop diuretic used for fluid
overload conditions.
3. Thiazide diuretics primarily act on which part of the nephron?
A. Proximal tubule
B. Descending limb

, C. Distal convoluted tubule
D. Collecting duct
Answer: C. Distal convoluted tubule
Rationale: Thiazides inhibit sodium and chloride reabsorption in
the distal convoluted tubule.
4. Which electrolyte imbalance is most commonly caused by loop
diuretics?
A. Hyperkalemia
B. Hypokalemia
C. Hypercalcemia
D. Hypermagnesemia
Answer: B. Hypokalemia
Rationale: Loop diuretics increase potassium excretion leading to
hypokalemia.
5. Which diuretic is potassium-sparing?
A. Bumetanide
B. Torsemide
C. Spironolactone
D. Metolazone
Answer: C. Spironolactone
Rationale: Spironolactone blocks aldosterone, conserving
potassium.
6. Which electrolyte drug is used to treat hypokalemia?
A. Sodium chloride
B. Calcium gluconate
C. Potassium chloride
D. Magnesium sulfate
Answer: C. Potassium chloride

, Rationale: Potassium chloride directly replaces potassium in
hypokalemic patients.
7. Mannitol is classified as which type of diuretic?
A. Loop
B. Thiazide
C. Potassium-sparing
D. Osmotic
Answer: D. Osmotic
Rationale: Mannitol increases osmolarity in renal tubules,
promoting water excretion.
8. Which condition is a common indication for loop diuretics?
A. Diabetes mellitus
B. Pulmonary edema
C. Hypothyroidism
D. Bronchial asthma
Answer: B. Pulmonary edema
Rationale: Loop diuretics rapidly reduce fluid overload in
pulmonary edema.
9. Thiazide diuretics decrease urinary calcium excretion. This makes
them useful in treating:
A. Hypercalcemia
B. Kidney stones due to calcium
C. Hypocalcemia
D. Osteomalacia
Answer: B. Kidney stones due to calcium
Rationale: Thiazides increase calcium reabsorption, reducing
urinary calcium.
10. Which adverse effect is associated with spironolactone?
A. Ototoxicity

, B. Gynecomastia
C. Hypoglycemia
D. Bradycardia
Answer: B. Gynecomastia
Rationale: Spironolactone has antiandrogenic effects that can
cause gynecomastia.


11. Which electrolyte abnormality may result from excessive
thiazide therapy?
A. Hyperkalemia
B. Hyponatremia
C. Hypernatremia
D. Hyperphosphatemia
Answer: B. Hyponatremia
Rationale: Thiazides increase sodium excretion and can cause
hyponatremia.
12. Which drug is classified as a thiazide diuretic?
A. Hydrochlorothiazide
B. Furosemide
C. Acetazolamide
D. Triamterene
Answer: A. Hydrochlorothiazide
Rationale: Hydrochlorothiazide is a commonly used thiazide
diuretic.
13. Acetazolamide acts by inhibiting which enzyme?
A. Aldosterone
B. Carbonic anhydrase
C. Sodium-potassium pump
D. Antidiuretic hormone