Amiloride MCQs With Answer offers B. Pharm students a focused, exam-oriented review of amiloride’s pharmacology. This concise introduction covers mechanism of action (ENaC blockade), potassium-sparing diuretic effects, renal site of action, therapeutic indications including hypertension, edematous states and Liddle’s syndrome, pharmacokinetics, dosing, monitoring, adverse effects such as hyperkalemia, and key drug interactions. Questions emphasize renal physiology, molecular targets, clinical application, laboratory monitoring and comparisons with other diuretics to deepen understanding. Carefully designed items promote application and critical thinking for exams and clinical scenarios. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which channel is directly blocked by amiloride in the renal tubule?
- Epithelial sodium channel (ENaC)
- Na+/K+ ATPase
- Na+/Cl- cotransporter (NCC)
- Na+-K+-2Cl- cotransporter (NKCC2)
Correct Answer: Epithelial sodium channel (ENaC)
Q2. Amiloride is classified pharmacologically as which type of diuretic?
- Thiazide diuretic
- Loop diuretic
- Potassium-sparing diuretic
- Carbonic anhydrase inhibitor
Correct Answer: Potassium-sparing diuretic
Q3. In which segment of the nephron does amiloride exert its primary action?
- Proximal convoluted tubule
- Thick ascending limb of Henle
- Distal convoluted tubule
- Collecting duct (principal cells)
Correct Answer: Collecting duct (principal cells)
Q4. What is the most likely electrolyte disturbance caused by therapeutic doses of amiloride?
- Hypokalemia
- Hyperkalemia
- Hypocalcemia
- Hypernatremia
Correct Answer: Hyperkalemia
Q5. Which diuretic class is commonly combined with amiloride to prevent hypokalemia while maintaining diuresis?
- Loop diuretics
- Thiazide diuretics
- Carbonic anhydrase inhibitors
- Osmotic diuretics
Correct Answer: Thiazide diuretics
Q6. Which statement correctly contrasts amiloride with spironolactone?
- Amiloride is an aldosterone receptor antagonist; spironolactone blocks ENaC
- Amiloride blocks ENaC directly; spironolactone is an aldosterone antagonist
- Both drugs are loop diuretics with identical mechanisms
- Spironolactone is a carbonic anhydrase inhibitor while amiloride is not
Correct Answer: Amiloride blocks ENaC directly; spironolactone is an aldosterone antagonist
Q7. What is the usual route of administration for amiloride in outpatient therapy?
- Intravenous
- Oral
- Intramuscular
- Topical
Correct Answer: Oral
Q8. Approximate oral bioavailability of amiloride is closest to which value?
- 10%
- 50%
- 90%
- 100%
Correct Answer: 50%
Q9. Typical onset of diuretic action after oral administration of amiloride is:
- 30 minutes
- 2–4 hours
- 24 hours
- 3–4 days
Correct Answer: 2–4 hours
Q10. The elimination half-life of amiloride in adults is approximately:
- 30 minutes
- 1–2 hours
- 6–9 hours
- 48–72 hours
Correct Answer: 6–9 hours
Q11. How is amiloride primarily eliminated from the body?
- Metabolized by liver and excreted in bile
- Excreted unchanged in urine
- Metabolized to active metabolites in plasma
- Exhaled via lungs as volatile metabolites
Correct Answer: Excreted unchanged in urine
Q12. Which adverse effect is most clinically significant and requires monitoring when a patient is on amiloride?
- Ototoxicity
- Methemoglobinemia
- Hyperkalemia
- Hypoglycemia
Correct Answer: Hyperkalemia
Q13. Amiloride is relatively contraindicated in patients with which condition?
- Severe renal impairment
- Mild hypertension controlled with diet
- Seasonal allergic rhinitis
- Stable hypothyroidism
Correct Answer: Severe renal impairment
Q14. Concurrent use of amiloride with which class of drugs greatly increases the risk of hyperkalemia?
- Angiotensin-converting enzyme (ACE) inhibitors
- Beta-2 adrenergic agonists
- Loop diuretics
- Thiazide diuretics
Correct Answer: Angiotensin-converting enzyme (ACE) inhibitors
Q15. Chemically, amiloride contains which key functional group that contributes to its activity?
- Guanidine moiety
- Sulfonamide group
- Thiazide ring
- Steroid nucleus
Correct Answer: Guanidine moiety
Q16. Which of the following transporters is NOT directly inhibited by amiloride?
- Epithelial sodium channel (ENaC)
- Na+/K+ ATPase
- Apical sodium conductance via ENaC in principal cells
- ENaC-mediated luminal Na+ entry
Correct Answer: Na+/K+ ATPase
Q17. What is the typical effect of amiloride on urinary calcium excretion?
- Marked increase in urinary calcium
- Decrease in urinary calcium excretion
- No effect on calcium handling
- Causes nephrolithiasis due to calcium precipitation
Correct Answer: Decrease in urinary calcium excretion
Q18. Before initiating amiloride therapy, which baseline laboratory tests are most important?
- Complete blood count and liver function tests
- Serum potassium and renal function (creatinine)
- Fasting lipid profile and HbA1c
- Coagulation profile and magnesium level
Correct Answer: Serum potassium and renal function (creatinine)
Q19. In suspected amiloride overdose with severe hyperkalemia, which acute therapy is appropriate to stabilize the patient?
- Oral potassium supplements
- Intravenous insulin with glucose
- Administer spironolactone
- Give high-dose thiazide diuretic
Correct Answer: Intravenous insulin with glucose
Q20. Which combination product commonly includes amiloride to mitigate potassium loss caused by the partner drug?
- Amiloride + furosemide
- Amiloride + hydrochlorothiazide
- Amiloride + acetazolamide
- Amiloride + spironolactone
Correct Answer: Amiloride + hydrochlorothiazide
Q21. Compared with triamterene, amiloride differs in which pharmacokinetic property?
- Amiloride is extensively metabolized by the liver while triamterene is excreted unchanged
- Amiloride is excreted primarily unchanged in urine; triamterene undergoes hepatic metabolism
- Both drugs have identical metabolic pathways
- Triamterene has a longer half-life due to renal excretion
Correct Answer: Amiloride is excreted primarily unchanged in urine; triamterene undergoes hepatic metabolism
Q22. Which genetic disorder characterized by increased ENaC activity can be treated with amiloride?
- Cystic fibrosis
- Liddle’s syndrome
- Gitelman syndrome
Correct Answer: Liddle’s syndrome
Q23. Amiloride can cause which acid-base disturbance due to reduced H+ secretion?
- Respiratory alkalosis
- Metabolic alkalosis
- Metabolic acidosis
- Respiratory acidosis
Correct Answer: Metabolic acidosis
Q24. Common therapeutic dosing for amiloride in adults is typically:
- 5–10 mg daily
- 50–100 mg daily
- 0.5–1 mg daily
- 100–200 mg daily
Correct Answer: 5–10 mg daily
Q25. In primary hyperaldosteronism, which abnormality does amiloride directly counteract?
- Excessive bicarbonate loss in urine
- Excess sodium reabsorption and increased potassium secretion
- Excessive water loss due to ADH deficiency
- Excessive proximal tubular glucose reabsorption
Correct Answer: Excess sodium reabsorption and increased potassium secretion
Q26. The principal mechanism by which amiloride lowers blood pressure is:
- Direct vasodilation via nitric oxide release
- Decreasing cardiac contractility
- Reducing renal sodium reabsorption leading to decreased plasma volume
- Blocking beta-adrenergic receptors
Correct Answer: Reducing renal sodium reabsorption leading to decreased plasma volume
Q27. Concurrent use of which of the following with amiloride is most likely to produce severe hyperkalemia?
- Furosemide
- Lisinopril (an ACE inhibitor)
- Hydrochlorothiazide
- Acetazolamide
Correct Answer: Lisinopril (an ACE inhibitor)
Q28. After initiating amiloride therapy, when is the earliest recommended time to recheck serum potassium in high-risk patients?
- 3–7 days after initiation
- 6 months after initiation
- Only if symptoms develop
- Every hour for the first 24 hours
Correct Answer: 3–7 days after initiation
Q29. The expected effect of amiloride on urinary sodium excretion is:
- Decrease urinary sodium excretion
- No change in urinary sodium excretion
- Increase urinary sodium excretion
- Convert sodium excretion to potassium excretion
Correct Answer: Increase urinary sodium excretion
Q30. At the molecular level, how does amiloride inhibit sodium transport in the collecting duct?
- It blocks the basolateral Na+/K+ ATPase pump
- It competes with aldosterone for receptor binding
- It binds to and blocks the pore of apical ENaC on the luminal membrane
- It inhibits the Na+-K+-2Cl- cotransporter in the loop of Henle
Correct Answer: It binds to and blocks the pore of apical ENaC on the luminal membrane
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