Hydroflumethiazide MCQs With Answer

Hydroflumethiazide MCQs With Answer

Hydroflumethiazide is a thiazide diuretic frequently studied by B. Pharm students for its role in treating hypertension and edema. This focused MCQ collection covers mechanism of action at the distal convoluted tubule, pharmacokinetics, therapeutic indications, electrolyte and metabolic adverse effects (hypokalemia, hypercalcemia, hyperglycemia, hyperuricemia), drug interactions (lithium, NSAIDs, digitalis), contraindications, monitoring and counselling points. Questions also explore structure–activity relationships, sulfonamide cross‑reactivity, renal handling and clinical application in combination therapy. Designed for exam preparation and clinical understanding, these items deepen pharmacology knowledge and practical patient care skills. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which of the following best describes the primary mechanism of action of hydroflumethiazide?

• Inhibition of Na+/K+ ATPase in the collecting duct
• Inhibition of the Na-Cl symporter in the distal convoluted tubule
• Blockade of the Na-K-2Cl cotransporter in the thick ascending limb
• Inhibition of carbonic anhydrase in the proximal tubule

Correct Answer: Inhibition of the Na-Cl symporter in the distal convoluted tubule

Q2. Hydroflumethiazide commonly causes which electrolyte disturbance?

• Hyperkalemia
• Hypokalemia
• Hypermagnesemia
• Hypocalcemia

Correct Answer: Hypokalemia

Q3. Compared with loop diuretics, thiazide diuretics like hydroflumethiazide are more likely to cause which of the following?

• Marked decrease in calcium reabsorption
• Increase in urinary calcium excretion
• Decrease in urinary calcium excretion
• Greater natriuresis in severe renal failure

Correct Answer: Decrease in urinary calcium excretion

Q4. A known adverse metabolic effect of hydroflumethiazide is:

• Hypoglycemia
• Improved insulin sensitivity
• Hyperglycemia
• Decreased LDL cholesterol

Correct Answer: Hyperglycemia

Q5. Which drug interaction is of major clinical concern with thiazide diuretics like hydroflumethiazide?

• Co-administration with lithium leading to increased lithium levels
• Co-administration with metformin leading to lactic acidosis
• Co-administration with acetaminophen causing hepatotoxicity
• Co-administration with ceftriaxone causing nephrolithiasis

Correct Answer: Co-administration with lithium leading to increased lithium levels

Q6. Thiazide diuretics are contraindicated or used with caution in which renal condition?

• Nephrotic-range proteinuria with preserved GFR
• Severe renal impairment with very low GFR
• Early-stage diabetic nephropathy with normal GFR
• Interstitial nephritis with normal GFR

Correct Answer: Severe renal impairment with very low GFR

Q7. Hydroflumethiazide’s effect on uric acid levels is best described as:

• Increases serum uric acid and may precipitate gout
• Decreases serum uric acid through enhanced excretion
• No effect on uric acid handling
• Reduces production of uric acid by the liver

Correct Answer: Increases serum uric acid and may precipitate gout

Q8. Which of the following monitoring tests is most important after initiating hydroflumethiazide?

• Serum electrolytes including sodium and potassium
• Serum amylase
• Serum troponin
• Pulmonary function tests

Correct Answer: Serum electrolytes including sodium and potassium

Q9. Thiazide diuretics exert antihypertensive effects through which long‑term mechanism beyond diuresis?

• Direct vasoconstriction of arterioles
• Reduction of peripheral vascular resistance via vascular smooth muscle relaxation
• Increased cardiac output
• Inhibition of renin secretion only

Correct Answer: Reduction of peripheral vascular resistance via vascular smooth muscle relaxation

Q10. Which adverse reaction is characteristically associated with thiazide diuretics and sunlight exposure?

• Photosensitivity rash
• Mucous membrane bleeding
• Severe neutropenia
• Blue‑gray skin discoloration

Correct Answer: Photosensitivity rash

Q11. Which statement about sulfonamide cross-reactivity with hydroflumethiazide is most accurate?

• All patients with sulfa antibiotic allergy will have severe reaction to thiazides
• Cross-reactivity is impossible because structures are unrelated
• Cross-reactivity is possible; caution is advised in patients with prior severe sulfonamide reactions
• Thiazides are safe in all patients with sulfonamide allergy without exception

Correct Answer: Cross-reactivity is possible; caution is advised in patients with prior severe sulfonamide reactions

Q12. Which of the following physiologic effects explains thiazide-induced metabolic alkalosis?

• Enhanced bicarbonate secretion in the proximal tubule
• Contraction alkalosis due to volume depletion and increased bicarbonate reabsorption
• Inhibition of renal HCO3- reabsorption causing metabolic acidosis
• Direct stimulation of respiratory drive causing CO2 loss

Correct Answer: Contraction alkalosis due to volume depletion and increased bicarbonate reabsorption

Q13. Thiazides typically have what effect on serum calcium?

• They lower serum calcium causing hypocalcemia
• They increase serum calcium by reducing urinary calcium excretion
• No clinically relevant effect on calcium
• They cause profound hypercalcemia in most patients

Correct Answer: They increase serum calcium by reducing urinary calcium excretion

Q14. Hydroflumethiazide is often combined with which antihypertensive class to produce additive blood pressure lowering?

• ACE inhibitors
• Calcium supplements
• Topical beta blockers
• Antifungals

Correct Answer: ACE inhibitors

Q15. Which of the following clinical uses is NOT a typical indication for hydroflumethiazide?

• Essential hypertension
• Edema associated with heart failure
• Acute pulmonary edema requiring rapid diuresis
• Prevention of calcium kidney stones in hypercalciuria

Correct Answer: Acute pulmonary edema requiring rapid diuresis

Q16. An important cardiovascular toxicity risk when thiazides produce hypokalemia is:

• Reduced efficacy of beta‑blockers
• Increased risk of digitalis toxicity and arrhythmias
• Complete heart block in all patients
• Hypertrophic cardiomyopathy

Correct Answer: Increased risk of digitalis toxicity and arrhythmias

Q17. Why do thiazide diuretics become less effective in severe renal failure?

• They are metabolized by the liver rather than excreted renally
• They require delivery of the drug to the distal tubule which is reduced when GFR is very low
• They are inhibited by uremic toxins in the plasma
• They are extensively protein bound and cannot reach the kidney

Correct Answer: They require delivery of the drug to the distal tubule which is reduced when GFR is very low

Q18. Thiazide-induced hyperuricemia is due to which renal mechanism?

• Increased uric acid production in the liver
• Decreased tubular secretion of uric acid in the proximal tubule
• Increased glomerular filtration of uric acid
• Enhanced renal excretion of uric acid

Correct Answer: Decreased tubular secretion of uric acid in the proximal tubule

Q19. Which laboratory parameter should be checked in a diabetic patient starting hydroflumethiazide?

• Thyroid stimulating hormone
• Fasting blood glucose
• Serum amylase
• Prostate specific antigen

Correct Answer: Fasting blood glucose

Q20. Regarding pharmacokinetics, thiazides like hydroflumethiazide are primarily eliminated by:

• Hepatic metabolism to inactive metabolites
• Renal excretion of unchanged drug
• Exhalation via the lungs
• Biliary excretion only

Correct Answer: Renal excretion of unchanged drug

Q21. In pregnancy, thiazide diuretics are generally:

• First‑line antihypertensives without restriction
• Used with caution and avoided if possible due to potential maternal volume depletion and fetal effects
• Contraindicated in all trimesters due to teratogenicity confirmed in humans
• Preferred because they reduce maternal edema without affecting fetus

Correct Answer: Used with caution and avoided if possible due to potential maternal volume depletion and fetal effects

Q22. Which lipid change may be seen with chronic thiazide therapy?

• Decrease in LDL cholesterol
• Increase in total cholesterol and triglycerides
• Marked reduction in triglycerides
• No changes in lipid profile

Correct Answer: Increase in total cholesterol and triglycerides

Q23. Which clinical counseling point is most appropriate for a patient starting hydroflumethiazide?

• Avoid potassium‑rich foods to prevent hyperkalemia
• Be aware of symptoms of low potassium such as muscle weakness and cramps
• Stop antihypertensive therapy immediately if dizziness occurs
• There is no need to monitor blood tests after starting therapy

Correct Answer: Be aware of symptoms of low potassium such as muscle weakness and cramps

Q24. Which co-prescribed medication can reduce the antihypertensive effect of thiazides by causing sodium and water retention?

• NSAIDs such as ibuprofen
• ACE inhibitors
• Potassium supplements
• Topical corticosteroids

Correct Answer: NSAIDs such as ibuprofen

Q25. For prevention of recurrent calcium kidney stones, thiazides are effective mainly because they:

• Increase urinary oxalate excretion
• Decrease urinary calcium excretion
• Raise urinary citrate concentration
• Acidify the urine substantially

Correct Answer: Decrease urinary calcium excretion

Q26. Which one of the following is a classical sign of thiazide overdose related to electrolyte imbalance?

• Severe hyperkalemia with peaked T waves
• Profound hyponatremia with confusion and seizures
• Marked hypocalcemia with tetany
• Acute lactic acidosis

Correct Answer: Profound hyponatremia with confusion and seizures

Q27. Which mechanism explains why thiazides potentiate the effect of certain antihypertensive agents like ACE inhibitors?

• Thiazides increase sympathetic tone which ACE inhibitors block
• Volume depletion from thiazides enhances vasodilation produced by ACE inhibitors
• Thiazides increase renin which ACE inhibitors cannot block
• No pharmacologic interaction exists between these classes

Correct Answer: Volume depletion from thiazides enhances vasodilation produced by ACE inhibitors

Q28. In a patient on hydroflumethiazide who develops muscle weakness, which immediate lab should be checked first?

• Serum potassium
• Serum bilirubin
• Platelet count
• Serum creatine kinase only

Correct Answer: Serum potassium

Q29. Which structural feature is common to thiazide diuretics like hydroflumethiazide that relates to their mechanism?

• Presence of a sulfonamide group
• Large peptide chain
• Beta‑lactam ring
• Purine base analog structure

Correct Answer: Presence of a sulfonamide group

Q30. When counseling an elderly patient starting hydroflumethiazide, which precaution is most important?

• There is no need to adjust for fall risk
• Monitor for orthostatic hypotension and risk of falls, and check electrolytes periodically
• Encourage high sodium intake to prevent dehydration
• Stop all other cardiovascular medications immediately

Correct Answer: Monitor for orthostatic hypotension and risk of falls, and check electrolytes periodically

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