Dichlorphenamide MCQs With Answer

Dichlorphenamide MCQs With Answer — This concise introduction is designed for B. Pharm students to build strong clinical and pharmacological understanding of dichlorphenamide, a sulfonamide carbonic anhydrase inhibitor. It covers mechanism of action, pharmacokinetics, therapeutic uses (notably primary periodic paralysis), adverse effects, monitoring, drug interactions, and practical considerations in dispensing and counselling. The focus is on clinical relevance: how dichlorphenamide alters renal bicarbonate handling, causes metabolic acidosis, affects electrolytes, and increases risk of renal calculi. These targeted points will help you prepare for exams and practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which pharmacological class does dichlorphenamide primarily belong to?

• Sulfonamide carbonic anhydrase inhibitor
• Loop diuretic
• Thiazide diuretic
• Potassium-sparing diuretic

Correct Answer: Sulfonamide carbonic anhydrase inhibitor

Q2. What is an FDA‑approved primary clinical indication for dichlorphenamide?

• Primary periodic paralysis
• Essential hypertension as first-line therapy
• Acute bacterial infections
• Congestive heart failure fluid overload

Correct Answer: Primary periodic paralysis

Q3. The main mechanism of action of dichlorphenamide in the kidney is:

• Inhibition of carbonic anhydrase in the proximal tubule, reducing bicarbonate reabsorption
• Blocking the Na+-K+-2Cl− cotransporter in the thick ascending limb
• Inhibition of sodium chloride reabsorption in the distal tubule
• Antagonism of aldosterone receptors in the collecting duct

Correct Answer: Inhibition of carbonic anhydrase in the proximal tubule, reducing bicarbonate reabsorption

Q4. Which acid–base change is commonly produced by dichlorphenamide therapy?

• Metabolic acidosis due to bicarbonate loss
• Metabolic alkalosis due to H+ loss
• Respiratory acidosis due to hypoventilation
• Respiratory alkalosis due to hyperventilation

Correct Answer: Metabolic acidosis due to bicarbonate loss

Q5. Dichlorphenamide typically causes which change in urine pH?

• Increased (more alkaline) urine pH
• Decreased (more acidic) urine pH
• No change in urine pH
• Initial decrease then sustained decrease in urine pH

Correct Answer: Increased (more alkaline) urine pH

Q6. A key adverse effect associated with dichlorphenamide is:

• Paresthesias and taste disturbances
• Severe hyperglycemia as the most common effect
• Ototoxicity similar to aminoglycosides
• Excessive potassium retention causing hyperkalemia

Correct Answer: Paresthesias and taste disturbances

Q7. Which electrolyte disturbance should be monitored during dichlorphenamide therapy?

• Serum bicarbonate and potassium levels
• Serum magnesium only
• Serum phosphate only
• No electrolyte monitoring is needed

Correct Answer: Serum bicarbonate and potassium levels

Q8. Compared with acetazolamide, dichlorphenamide is generally considered to be:

• Longer acting and suitable for chronic oral use in periodic paralysis
• A short‑acting topical carbonic anhydrase inhibitor only
• Less potent and never used clinically
• Identical in every pharmacokinetic parameter

Correct Answer: Longer acting and suitable for chronic oral use in periodic paralysis

Q9. Which patient history is a clear contraindication to using dichlorphenamide?

• Severe allergy to sulfonamide drugs
• Seasonal allergic rhinitis without drug allergy
• Mild myopia corrected with glasses
• History of well-controlled peptic ulcer disease

Correct Answer: Severe allergy to sulfonamide drugs

Q10. Which renal calculus type risk is increased by chronic dichlorphenamide therapy?

• Calcium phosphate stones due to alkaline urine
• Cystine stones caused by increased cystine excretion
• Struvite stones from increased urinary ammonia

Correct Answer: Calcium phosphate stones due to alkaline urine

Q11. The primary site of action of dichlorphenamide in the nephron is the:

• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule
• Collecting duct principal cells

Correct Answer: Proximal convoluted tubule

Q12. Which laboratory parameter would you expect to decrease during effective dichlorphenamide therapy?

• Serum bicarbonate
• Blood urea nitrogen as a primary effect
• Serum calcium markedly
• Serum creatine kinase

Correct Answer: Serum bicarbonate

Q13. Dichlorphenamide’s therapeutic benefit in periodic paralysis is thought to result from:

• Induction of a mild metabolic acidosis that stabilizes muscle membrane excitability
• Direct blockade of voltage-gated Na+ channels in skeletal muscle
• Increasing insulin secretion to lower blood potassium
• Acting as a beta-2 agonist to shift potassium intracellularly

Correct Answer: Induction of a mild metabolic acidosis that stabilizes muscle membrane excitability

Q14. Which drug interaction is clinically relevant with dichlorphenamide?

• Concomitant use with other carbonic anhydrase inhibitors increases adverse effects
• Concurrent use with antibiotics universally enhances antibiotic effect
• Dichlorphenamide prevents warfarin anticoagulation completely
• It neutralizes the effect of insulin

Correct Answer: Concomitant use with other carbonic anhydrase inhibitors increases adverse effects

Q15. The recommended route of administration for dichlorphenamide in clinical use is:

• Oral tablets
• Topical ophthalmic drops only
• Intravenous infusion exclusively
• Intramuscular injection

Correct Answer: Oral tablets

Q16. Which sign/symptom should prompt immediate evaluation for dichlorphenamide toxicity?

• Marked lethargy, severe paresthesia, or profound metabolic acidosis
• Intermittent sneezing and mild headache
• Improvement in muscle strength only
• Transient increase in appetite

Correct Answer: Marked lethargy, severe paresthesia, or profound metabolic acidosis

Q17. During counselling, which point is important to tell patients starting dichlorphenamide?

• Report new numbness, taste changes, or signs of stone formation promptly
• It is safe to combine with any over‑the‑counter diuretic without advice
• There is no need to monitor blood tests during therapy
• It will immediately cure all muscle weakness permanently

Correct Answer: Report new numbness, taste changes, or signs of stone formation promptly

Q18. Which urine change is directly caused by dichlorphenamide’s inhibition of carbonic anhydrase?

• Increased urinary bicarbonate excretion
• Decreased urinary glucose excretion
• Increased urinary urea excretion exclusively
• Marked decrease in urinary sodium with no bicarbonate change

Correct Answer: Increased urinary bicarbonate excretion

Q19. Which patient population requires caution or dose adjustment with dichlorphenamide?

• Patients with significant renal impairment
• Young healthy adults with no comorbidity
• Patients with well‑controlled seasonal allergies only
• Individuals with isolated hyperlipidemia without renal disease

Correct Answer: Patients with significant renal impairment

Q20. Which adverse effect is most directly linked to dichlorphenamide’s sulfonamide structure?

• Allergic reactions including rash and hypersensitivity
• Classic ototoxicity characterized by tinnitus
• Hyperglycemia as a class‑specific effect
• Agranulocytosis as the most common reaction

Correct Answer: Allergic reactions including rash and hypersensitivity

Q21. Which physiologic parameter is reduced in the eye by systemic carbonic anhydrase inhibitors like dichlorphenamide?

• Aqueous humor formation leading to lower intraocular pressure
• Retinal blood flow causing ischemia
• Corneal thickness by direct collagen degradation
• Pupil constriction via parasympathetic blockade

Correct Answer: Aqueous humor formation leading to lower intraocular pressure

Q22. In case of suspected overdose of dichlorphenamide, the primary management is:

• Supportive care and correction of acid–base and electrolyte disturbances
• Immediate administration of naloxone
• Gastric lavage followed by whole bowel irrigation for metal chelation
• High-dose insulin therapy as first-line antidote

Correct Answer: Supportive care and correction of acid–base and electrolyte disturbances

Q23. Which monitoring schedule is appropriate after initiating dichlorphenamide?

• Baseline and periodic serum electrolytes and renal function tests
• No monitoring is necessary after the first dose
• Only liver function tests are required weekly
• Continuous cardiac telemetry for all outpatients

Correct Answer: Baseline and periodic serum electrolytes and renal function tests

Q24. Which of the following is NOT an expected pharmacological effect of dichlorphenamide?

• Direct antimicrobial activity against gram-negative bacteria
• Promotion of bicarbonate diuresis
• Potential lowering of serum bicarbonate levels
• Alkalinization of urine

Correct Answer: Direct antimicrobial activity against gram-negative bacteria

Q25. For which reason might dichlorphenamide therapy be discontinued?

• Development of severe metabolic acidosis or intolerable adverse effects
• Resolution of seasonal allergies
• Improvement in visual acuity unrelated to therapy
• Minor transient headache after the first dose

Correct Answer: Development of severe metabolic acidosis or intolerable adverse effects

Q26. Which is a common non‑laboratory adverse complaint reported with dichlorphenamide?

• Fatigue and cognitive slowing
• Excessive hair growth (hypertrichosis)
• Marked euphoria and insomnia
• Immediate severe joint pain in all patients

Correct Answer: Fatigue and cognitive slowing

Q27. In pharmacology exams, dichlorphenamide is often grouped with other drugs that:

• Inhibit carbonic anhydrase enzymes
• Act as direct renin inhibitors
• Antagonize beta-adrenergic receptors
• Stimulate aldosterone secretion

Correct Answer: Inhibit carbonic anhydrase enzymes

Q28. Which counselling point is relevant regarding kidney stone prevention when taking dichlorphenamide?

• Maintain good hydration and report flank pain or hematuria
• Avoid all dietary calcium completely
• Take extra vitamin C to prevent stones
• Restrict fluid intake to reduce urinary output

Correct Answer: Maintain good hydration and report flank pain or hematuria

Q29. Which statement about dichlorphenamide’s chemical nature is correct?

• It is a sulfonamide derivative that inhibits carbonic anhydrase
• It is a peptide antibiotic derived from penicillin
• It is a steroidal anti‑inflammatory agent
• It is a monoclonal antibody used in immunotherapy

Correct Answer: It is a sulfonamide derivative that inhibits carbonic anhydrase

Q30. What is the primary therapeutic goal when using dichlorphenamide for periodic paralysis?

• Reduce the frequency and severity of paralysis attacks
• Completely cure the genetic defect causing the disease
• Raise fasting blood glucose to prevent attacks
• Induce profound diuresis to eliminate potassium

Correct Answer: Reduce the frequency and severity of paralysis attacks

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