Methazolamide MCQs With Answer

Methazolamide MCQs With Answer: This focused introduction reviews methazolamide, a sulfonamide-derived carbonic anhydrase inhibitor used in glaucoma management and select systemic indications. B.Pharm students will learn pharmacology, mechanism of action, pharmacokinetics, clinical uses, dosing considerations, adverse effects (metabolic acidosis, paresthesia, renal calculi), contraindications, drug interactions, and monitoring parameters. Emphasis is on proximal tubular effects, reduction of aqueous humor secretion, and differences from acetazolamide to inform rational prescribing and patient counseling. Questions emphasize mechanism, adverse reactions, monitoring, dosing adjustments, and practical case-based scenarios relevant to pharmacy exams and patient care. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary pharmacological classification of methazolamide?

• Loop diuretic
• Carbonic anhydrase inhibitor
• Potassium-sparing diuretic
• Thiazide diuretic

Correct Answer: Carbonic anhydrase inhibitor

Q2. Which ocular effect is the main therapeutic action of methazolamide in glaucoma?

• Increased trabecular outflow
• Decreased aqueous humor production
• Mydriasis to improve drainage
• Contraction of ciliary muscle to open angle

Correct Answer: Decreased aqueous humor production

Q3. Methazolamide produces diuresis primarily by inhibiting bicarbonate reabsorption in which nephron segment?

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

Correct Answer: Proximal convoluted tubule

Q4. A common metabolic disturbance caused by methazolamide is:

• Metabolic alkalosis
• Respiratory acidosis
• Metabolic acidosis
• Respiratory alkalosis

Correct Answer: Metabolic acidosis

Q5. Which adverse effect is characteristic of carbonic anhydrase inhibitors like methazolamide?

• Hyperkalemia
• Hypokalemia
• Hypoglycemia
• Hypercalcemia

Correct Answer: Hypokalemia

Q6. Methazolamide is chemically related to which functional group important for allergy considerations?

• Penicillin nucleus
• Sulfonamide moiety
• Benzodiazepine ring
• Quinoline backbone

Correct Answer: Sulfonamide moiety

Q7. Which patient history is a relative contraindication to starting methazolamide?

• History of sulfonamide hypersensitivity
• Controlled hypothyroidism on levothyroxine
• Past resolved peptic ulcer disease
• Seasonal allergic rhinitis

Correct Answer: History of sulfonamide hypersensitivity

Q8. Compared with acetazolamide, methazolamide is generally considered to have:

• Shorter duration of action and poorer oral absorption
• Greater ocular penetration and longer duration of action
• No carbonic anhydrase inhibitory activity
• Exclusive topical use only

Correct Answer: Greater ocular penetration and longer duration of action

Q9. Which laboratory parameter should be monitored routinely during methazolamide therapy?

• Serum amylase
• Serum bicarbonate and electrolytes
• Fasting blood glucose only
• Liver enzymes weekly in all patients

Correct Answer: Serum bicarbonate and electrolytes

Q10. Methazolamide increases urinary pH which predisposes to formation of which type of kidney stones?

• Uric acid stones
• Calcium oxalate stones
• Calcium phosphate stones
• Cystine stones

Correct Answer: Calcium phosphate stones

Q11. The mechanism by which methazolamide lowers intraocular pressure is best described as:

• Enhanced trabecular meshwork phagocytosis
• Inhibition of carbonic anhydrase in ciliary epithelium reducing bicarbonate production
• Blockade of muscarinic receptors in the iris
• Activation of beta-adrenergic receptors in the eye

Correct Answer: Inhibition of carbonic anhydrase in ciliary epithelium reducing bicarbonate production

Q12. Which systemic indication (off-label or limited use) might warrant carbonic anhydrase inhibitor therapy including methazolamide?

• Chronic heart failure as first-line therapy
• Acute bacterial infections
• Altitude sickness prophylaxis or treatment
• Primary hypothyroidism

Correct Answer: Altitude sickness prophylaxis or treatment

Q13. Which symptom is a common sensory adverse effect reported with methazolamide?

• Tinnitus
• Paresthesia (tingling)
• Hyperacusis
• Diplopia only

Correct Answer: Paresthesia (tingling)

Q14. In patients with severe renal impairment, methazolamide dosing should be:

• Increased to overcome reduced clearance
• Unchanged regardless of renal function
• Reduced or avoided due to decreased drug clearance and risk of toxicity
• Replaced with a loop diuretic for glaucoma control

Correct Answer: Reduced or avoided due to decreased drug clearance and risk of toxicity

Q15. A pharmacist counseling a patient on methazolamide should warn about which acid-base sign to report immediately?

• Shortness of taste
• Progressive deep and rapid breathing suggesting metabolic acidosis
• Decreased thirst without other symptoms
• Intermittent joint pain unrelated to medication

Correct Answer: Progressive deep and rapid breathing suggesting metabolic acidosis

Q16. Which drug interaction is clinically relevant with methazolamide?

• Concomitant use with high-dose aspirin may increase risk of metabolic acidosis
• Methazolamide neutralizes the effect of warfarin
• Methazolamide causes increased clearance of digoxin leading to reduced effect
• No known interactions with any common drugs

Correct Answer: Concomitant use with high-dose aspirin may increase risk of metabolic acidosis

Q17. The therapeutic goal when using methazolamide in glaucoma is to:

• Completely reverse optic nerve cupping
• Reduce intraocular pressure to prevent or slow optic nerve damage
• Increase pupil dilation permanently
• Eliminate need for topical therapy in all patients

Correct Answer: Reduce intraocular pressure to prevent or slow optic nerve damage

Q18. Which monitoring parameter is particularly important during prolonged methazolamide therapy to detect electrolyte disturbances?

• Platelet count monthly
• Serum sodium and potassium levels periodically
• Serum magnesium only
• Urine specific gravity daily

Correct Answer: Serum sodium and potassium levels periodically

Q19. Methazolamide’s effect on urine composition that can influence drug excretion is primarily:

• Decreasing urine pH (acidifying urine)
• Increasing urine pH (alkalinizing urine)
• Lowering urine volume exclusively
• Making urine protein-rich

Correct Answer: Increasing urine pH (alkalinizing urine)

Q20. Which adverse hematologic reaction has been reported with sulfonamide carbonic anhydrase inhibitors and should prompt discontinuation?

• Agranulocytosis or aplastic anemia
• Iron-deficiency anemia due to blood loss
• Chronic lymphocytosis that is harmless
• Isolated thrombocytosis only

Correct Answer: Agranulocytosis or aplastic anemia

Q21. For acute closed-angle glaucoma, methazolamide is:

• The only agent needed immediately to lower pressure
• Contraindicated because it increases intraocular pressure
• Potentially useful as an adjunct to rapid pressure-lowering measures
• Effective only when given topically

Correct Answer: Potentially useful as an adjunct to rapid pressure-lowering measures

Q22. Which patient population requires extra caution or avoidance of methazolamide due to risk of serious reactions?

• Patients with history of deep vein thrombosis
• Pregnant women in first trimester without risk-benefit assessment
• Patients with controlled asthma
• Younger adults with seasonal allergies

Correct Answer: Pregnant women in first trimester without risk-benefit assessment

Q23. The onset of action for oral methazolamide in lowering intraocular pressure is typically:

• Within minutes after oral dose
• Within hours, with maximal effect over 24–48 hours
• After several weeks only
• No systemic oral effect on intraocular pressure

Correct Answer: Within hours, with maximal effect over 24–48 hours

Q24. Which symptom pair should prompt immediate discontinuation and medical review when a patient starts methazolamide?

• Mild dry mouth and transient cough
• Rash and fever suggestive of hypersensitivity reaction
• Occasional headache and mild blurred vision
• Nasal congestion and mild sneezing

Correct Answer: Rash and fever suggestive of hypersensitivity reaction

Q25. Methazolamide’s ability to produce metabolic acidosis can be therapeutically exploited in which condition?

• To treat respiratory alkalosis exclusively
• To reduce urinary stone formation in all stone types
• To enhance ventilation in some forms of sleep apnea
• To alkalinize urine and treat specific drug overdoses requiring alkaline urine

Correct Answer: To alkalinize urine and treat specific drug overdoses requiring alkaline urine

Q26. When counseling about methazolamide, which over-the-counter agent should patients be warned about due to increased acidosis risk at high doses?

• Acetaminophen at normal doses
• High-dose aspirin (salicylates)
• Pseudoephedrine nasal decongestant at recommended dosing
• Topical hydrocortisone cream

Correct Answer: High-dose aspirin (salicylates)

Q27. The primary reason methazolamide can cause paresthesias and CNS symptoms is:

• Direct muscarinic receptor stimulation in peripheral nerves
• Crossing the blood–brain barrier and altering CNS carbonic anhydrase activity
• Increasing serum calcium to neurotoxic levels
• Blocking sodium channels in peripheral neurons exclusively

Correct Answer: Crossing the blood–brain barrier and altering CNS carbonic anhydrase activity

Q28. Which statement about methazolamide pharmacokinetics is correct?

• It is administered only by intravenous route
• It is orally active and undergoes renal excretion
• It is entirely metabolized by hepatic CYP450 enzymes with no renal excretion
• It is not absorbed orally and used only topically

Correct Answer: It is orally active and undergoes renal excretion

Q29. In a patient on chronic methazolamide therapy, which electrolyte disturbance is least likely?

• Hypokalemia
• Hyponatremia
• Metabolic acidosis
• Hypermagnesemia due to increased retention

Correct Answer: Hypermagnesemia due to increased retention

Q30. For B.Pharm students, understanding methazolamide’s role emphasizes which professional responsibility?

• Prescribing antibiotics for ocular infections
• Rational drug selection, monitoring adverse effects, and counseling patients about risks and interactions
• Performing ocular surgery independently
• Replacing all topical glaucoma agents with systemic therapy routinely

Correct Answer: Rational drug selection, monitoring adverse effects, and counseling patients about risks and interactions

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