Introduction
The pharmacology of diuretics is a core topic for B. Pharm students, covering drug classes such as loop diuretics, thiazides, potassium-sparing agents, carbonic anhydrase inhibitors and osmotic diuretics. This topic explores mechanisms of action in specific nephron segments, pharmacokinetics, indications (hypertension, edema, heart failure, renal disease), adverse effects (electrolyte disturbances, metabolic alkalosis/acidosis, hyperuricemia), and clinically important drug interactions. Understanding receptor/transporter targets, dose-response relationships, monitoring parameters and strategies to manage diuretic resistance is essential. Mastery of these concepts links renal physiology with therapeutic decision-making. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which nephron segment is the primary site of action for loop diuretics such as furosemide?
- Proximal convoluted tubule
- Thick ascending limb of Henle’s loop
- Distal convoluted tubule
- Collecting duct
Correct Answer: Thick ascending limb of Henle’s loop
Q2. Which transporter is inhibited by thiazide diuretics like hydrochlorothiazide?
- Na+/K+/2Cl- cotransporter (NKCC2)
- Na+/Cl- cotransporter (NCC)
- Epithelial sodium channel (ENaC)
- Na+/H+ exchanger (NHE3)
Correct Answer: Na+/Cl- cotransporter (NCC)
Q3. Spironolactone primarily antagonizes which receptor to produce a potassium-sparing effect?
- Beta-1 adrenergic receptor
- Mineralocorticoid (aldosterone) receptor
- Angiotensin II receptor (AT1)
- Vasopressin V2 receptor
Correct Answer: Mineralocorticoid (aldosterone) receptor
Q4. Mannitol produces diuresis mainly by which mechanism?
- Inhibition of Na+/K+/2Cl- cotransporter
- Carbonic anhydrase inhibition
- Osmotic retention of water in the tubular lumen
- Blockade of aldosterone receptors
Correct Answer: Osmotic retention of water in the tubular lumen
Q5. Carbonic anhydrase inhibitors (e.g., acetazolamide) cause which primary acid-base disturbance?
- Metabolic alkalosis
- Respiratory acidosis
- Metabolic acidosis
- Respiratory alkalosis
Correct Answer: Metabolic acidosis
Q6. Which adverse effect is most characteristic of loop diuretics?
- Hyperkalemia
- Ototoxicity
- Hypoglycemia
- Metabolic acidosis
Correct Answer: Ototoxicity
Q7. A patient on thiazide diuretics is at risk for which electrolyte abnormality?
- Hyperkalemia
- Hypokalemia
- Hypermagnesemia
- Hyponatremia only
Correct Answer: Hypokalemia
Q8. Which diuretic class is most effective in patients with severely reduced glomerular filtration rate (GFR)?
- Thiazide diuretics
- Loop diuretics
- Carbonic anhydrase inhibitors
- Potassium-sparing diuretics
Correct Answer: Loop diuretics
Q9. Which diuretic increases calcium reabsorption in the distal tubule and can reduce risk of kidney stones?
- Furosemide
- Hydrochlorothiazide
- Acetazolamide
- Spironolactone
Correct Answer: Hydrochlorothiazide
Q10. Which interaction increases risk of hyperkalemia when combined with potassium-sparing diuretics?
- Loop diuretics
- Thiazide diuretics
- ACE inhibitors or ARBs
- Carbonic anhydrase inhibitors
Correct Answer: ACE inhibitors or ARBs
Q11. Which diuretic is contraindicated in patients with sulfonamide allergy due to structural similarity?
- Mannitol
- Loop diuretics (e.g., furosemide)
- Spironolactone
- Amiloride
Correct Answer: Loop diuretics (e.g., furosemide)
Q12. Which transporter’s inhibition by amiloride produces its diuretic effect?
- Na+/K+/2Cl- cotransporter
- Na+/Cl- cotransporter
- Epithelial sodium channel (ENaC)
- H+/K+ ATPase
Correct Answer: Epithelial sodium channel (ENaC)
Q13. Which diuretic is commonly used to reduce intracranial pressure acutely?
- Hydrochlorothiazide
- Mannitol
- Spironolactone
- Acetazolamide only for glaucoma
Correct Answer: Mannitol
Q14. Which metabolic disturbance is commonly caused by thiazide diuretics and can precipitate gout?
- Hypouricemia
- Hyperuricemia
- Hypomagnesemia
- Respiratory alkalosis
Correct Answer: Hyperuricemia
Q15. In treating pulmonary edema secondary to acute heart failure, which diuretic is preferred for rapid fluid removal?
- Hydrochlorothiazide
- Loop diuretic (e.g., furosemide) IV
- Spironolactone oral
- Acetazolamide IV
Correct Answer: Loop diuretic (e.g., furosemide) IV
Q16. Which genetic syndrome mimics chronic loop diuretic use and presents with metabolic alkalosis, hypokalemia, and hypercalciuria?
- Gitelman syndrome
- Bartter syndrome
- Liddle syndrome
- Nephrogenic diabetes insipidus
Correct Answer: Bartter syndrome
Q17. Liddle syndrome is characterized by which primary defect that leads to hypertension and hypokalemia?
- Gain-of-function mutation of ENaC increasing sodium reabsorption
- Loss-of-function mutation of NCC decreasing sodium reabsorption
- Excess aldosterone production
- Inhibition of Na+/K+/2Cl- cotransporter
Correct Answer: Gain-of-function mutation of ENaC increasing sodium reabsorption
Q18. Which diuretic is indicated for metabolic alkalosis due to its ability to promote bicarbonate excretion?
- Acetazolamide
- Furosemide
- Spironolactone
- Hydrochlorothiazide
Correct Answer: Acetazolamide
Q19. Combining a thiazide with a potassium-sparing diuretic primarily aims to:
- Increase calcium excretion
- Enhance sodium retention
- Prevent hypokalemia caused by thiazide
- Cause metabolic acidosis
Correct Answer: Prevent hypokalemia caused by thiazide
Q20. Which adverse effect is specifically associated with spironolactone but less with eplerenone?
- Gynecomastia and endocrine effects
- Hyperuricemia
- Ototoxicity
- Hypoglycemia
Correct Answer: Gynecomastia and endocrine effects
Q21. NSAIDs reduce the natriuretic response to which diuretic class by inhibiting prostaglandin synthesis?
- Loop diuretics
- Thiazide diuretics
- Potassium-sparing diuretics
- Osmotic diuretics
Correct Answer: Loop diuretics
Q22. The “braking phenomenon” or diuretic resistance refers to:
- Immediate allergic reactions to diuretics
- Progressive sodium retention and reduced diuretic efficacy over time
- Excessive kaliuresis after a single dose
- Increase in urine osmolality despite diuretic use
Correct Answer: Progressive sodium retention and reduced diuretic efficacy over time
Q23. Which laboratory parameter is essential to monitor when a patient is started on loop diuretics?
- Serum potassium and magnesium
- Serum bilirubin only
- Serum amylase
- Serum vitamin B12
Correct Answer: Serum potassium and magnesium
Q24. Which diuretic would be most appropriate to reduce intraocular pressure in acute angle-closure glaucoma?
- Topical thiazide
- Acetazolamide
- Spironolactone
- Amiloride
Correct Answer: Acetazolamide
Q25. Which statement about thiazide diuretics’ effect on glucose metabolism is correct?
- They always cause severe hypoglycemia
- They may cause mild hyperglycemia by impairing insulin secretion and sensitivity
- They improve insulin sensitivity
- They have no effect on glucose metabolism
Correct Answer: They may cause mild hyperglycemia by impairing insulin secretion and sensitivity
Q26. In a patient with hepatic cirrhosis and ascites, which diuretic is commonly used as first-line therapy?
- Loop diuretic alone
- Spironolactone often with a loop diuretic
- Thiazide diuretic alone
- Acetazolamide alone
Correct Answer: Spironolactone often with a loop diuretic
Q27. Which parameter increases after administering a potent loop diuretic due to increased delivery of Na+ to distal nephron?
- Urinary potassium excretion
- Renin suppression only
- Serum calcium concentration
- Urinary glucose excretion
Correct Answer: Urinary potassium excretion
Q28. Which diuretic class can cause hypomagnesemia as a common adverse effect?
- Potassium-sparing diuretics
- Loop diuretics and thiazides
- Carbonic anhydrase inhibitors only
- Osmotic diuretics only
Correct Answer: Loop diuretics and thiazides
Q29. Therapeutic use of acetazolamide includes all EXCEPT:
- Altitude sickness prophylaxis
- Open-angle glaucoma treatment
- Long-term systemic diuresis for congestive heart failure
- Metabolic alkalosis correction
Correct Answer: Long-term systemic diuresis for congestive heart failure
Q30. Which principle explains the increased efficacy when combining loop and thiazide diuretics?
- Synergistic blockade of sequential nephron sodium reabsorption sites
- Both act on the same transporter causing additive inhibition
- Thiazide prevents loop-induced calcium loss only
- Combination reduces aldosterone secretion directly
Correct Answer: Synergistic blockade of sequential nephron sodium reabsorption sites
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
Mail- Sachin@pharmacyfreak.com