Disopyramide phosphate MCQs With Answer

Disopyramide phosphate MCQs With Answer provide B. Pharm students a focused review of disopyramide pharmacology, therapeutic uses, adverse effects, pharmacokinetics, drug interactions, contraindications and monitoring. This set emphasizes Class IA antiarrhythmic mechanisms — fast sodium-channel blockade, prolongation of action potential and QT interval — and clinically important properties such as strong anticholinergic activity, negative inotropy, hepatic metabolism with renal excretion, and proarrhythmic risk. Questions explore dosing principles, toxicity management, ECG interpretation, and practical considerations for special populations. These targeted multiple-choice questions reinforce core concepts and apply pharmaceutical reasoning to real-world clinical scenarios. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which class of antiarrhythmic drugs does disopyramide belong to?

• Class IA antiarrhythmic
• Class IB antiarrhythmic
• Class IC antiarrhythmic
• Class III antiarrhythmic

Correct Answer: Class IA antiarrhythmic

Q2. What is the primary electrophysiological mechanism of disopyramide?

• Block of fast sodium channels slowing Phase 0 depolarization
• Beta-adrenergic receptor blockade
• Potassium channel blockade prolonging Phase 3 only
• Calcium channel blockade reducing contractility

Correct Answer: Block of fast sodium channels slowing Phase 0 depolarization

Q3. Which ECG changes are commonly associated with disopyramide therapy?

• Shortening of QT interval and narrowing of QRS
• Prolongation of action potential duration and QT interval
• No significant ECG changes
• Only bradycardia without conduction changes

Correct Answer: Prolongation of action potential duration and QT interval

Q4. Disopyramide is notable for which prominent non-cardiac pharmacologic property?

• Strong anticholinergic activity
• Potent cholinesterase inhibition
• Significant serotonergic agonism
• Major histamine H1 antagonism

Correct Answer: Strong anticholinergic activity

Q5. Which cardiovascular adverse effect is most clinically important with disopyramide?

• Positive inotropy increasing cardiac output
• Negative inotropy that can worsen heart failure
• Marked vasodilation causing hypotension
• Selective coronary vasospasm

Correct Answer: Negative inotropy that can worsen heart failure

Q6. Disopyramide can be useful in symptomatic hypertrophic obstructive cardiomyopathy primarily because it:

• Increases myocardial contractility and reduces obstruction
• Produces negative inotropy, reducing LV outflow tract obstruction
• Acts as a vasodilator to decrease afterload
• Is a potent diuretic reducing preload

Correct Answer: Produces negative inotropy, reducing LV outflow tract obstruction

Q7. Which condition is a classic contraindication for disopyramide because of its anticholinergic effects?

• Acute narrow-angle glaucoma
• Hyperthyroidism
• Stable angina
• Mild controlled hypertension

Correct Answer: Acute narrow-angle glaucoma

Q8. Which combination of side effects best reflects disopyramide’s anticholinergic profile?

• Diarrhea, excessive sweating, bradycardia
• Dry mouth, blurred vision, constipation, urinary retention
• Rash, eosinophilia, photosensitivity
• Excessive lacrimation, rhinorrhea, salivation

Correct Answer: Dry mouth, blurred vision, constipation, urinary retention

Q9. What is the primary route of elimination for disopyramide and its metabolites?

• Hepatic metabolism with renal excretion of metabolites
• Primarily unchanged renal excretion only
• Biliary excretion as unchanged drug into feces
• Exhalation via lungs

Correct Answer: Hepatic metabolism with renal excretion of metabolites

Q10. Which monitoring is essential when a patient is started on disopyramide?

• Regular ECG, renal and hepatic function tests
• Only periodic blood glucose monitoring
• No monitoring required for stable patients
• Only dermatologic examination

Correct Answer: Regular ECG, renal and hepatic function tests

Q11. True or False: Combining disopyramide with other QT-prolonging drugs increases the risk of torsades de pointes.

• True
• False
• Only if patient is elderly
• Only when renal function is normal

Correct Answer: True

Q12. Which co-administered drug is most likely to increase disopyramide plasma levels by inhibiting hepatic metabolism?

• Ketoconazole
• Rifampin
• Amoxicillin
• Metformin

Correct Answer: Ketoconazole

Q13. In severe disopyramide overdose with wide QRS and ventricular arrhythmia, which acute intervention may be useful?

• Intravenous sodium bicarbonate
• High-dose insulin only
• Immediate oral activated charcoal after 24 hours
• Whole-bowel irrigation as first-line

Correct Answer: Intravenous sodium bicarbonate

Q14. Disopyramide’s effect on AV nodal conduction typically results in which ECG change?

• Prolongation of PR interval
• Shortening of PR interval
• No change in PR interval
• Complete heart block in all patients

Correct Answer: Prolongation of PR interval

Q15. Which patient is least suitable for disopyramide therapy?

• Patient with decompensated heart failure and reduced ejection fraction
• Patient with well-controlled supraventricular tachycardia and normal EF
• Patient with symptomatic hypertrophic cardiomyopathy without HF
• Patient requiring treatment for life-threatening ventricular arrhythmias

Correct Answer: Patient with decompensated heart failure and reduced ejection fraction

Q16. What formulations of disopyramide are commonly available for clinical use?

• Oral tablets and parenteral (IV) injection
• Only topical cream
• Only inhalation aerosol
• Transdermal patch only

Correct Answer: Oral tablets and parenteral (IV) injection

Q17. The anticholinergic effects of disopyramide result from antagonism of which receptor type?

• Muscarinic acetylcholine receptors
• Nicotinic acetylcholine receptors
• Benzodiazepine receptors
• Beta-2 adrenergic receptors

Correct Answer: Muscarinic acetylcholine receptors

Q18. Disopyramide is most appropriately used for which type of arrhythmia?

• Life-threatening ventricular arrhythmias
• Migraine-associated aura
• Benign premature atrial complexes only
• Essential palpitations without ECG changes

Correct Answer: Life-threatening ventricular arrhythmias

Q19. Which ECG manifestation reflects slowed intraventricular conduction caused by disopyramide?

• Widening of the QRS complex
• Shortening of QRS duration
• Peaked T waves only
• Delta waves appearance

Correct Answer: Widening of the QRS complex

Q20. Disopyramide’s effect on refractoriness most commonly leads to:

• Prolongation of the effective refractory period
• Shortening of the refractory period
• No change in refractory properties
• Immediate loss of refractory period

Correct Answer: Prolongation of the effective refractory period

Q21. Should dosing of disopyramide be adjusted in patients with significant renal impairment?

• Yes — dose adjustments and careful monitoring are needed
• No — renal function has no impact on dosing
• Only liver function matters for dosing
• Only age determines dosing, not renal function

Correct Answer: Yes — dose adjustments and careful monitoring are needed

Q22. Which of the following is a common urinary side effect of disopyramide?

• Urinary retention
• Polyuria due to diuresis
• Hematuria as a primary effect
• Frequent nocturnal urination (nocturia)

Correct Answer: Urinary retention

Q23. Which drug is NOT a Class IA antiarrhythmic?

• Lidocaine
• Quinidine
• Procainamide
• Disopyramide

Correct Answer: Lidocaine

Q24. Which potentially life-threatening arrhythmia is associated with excessive QT prolongation from disopyramide?

• Torsades de pointes
• Sinus tachycardia only
• Atrial flutter without ventricular involvement
• Ventricular fibrillation unrelated to QT length

Correct Answer: Torsades de pointes

Q25. A patient on disopyramide reports increased eye pain and blurred vision; this is most consistent with:

• Exacerbation of narrow-angle glaucoma due to anticholinergic action
• Allergic conjunctivitis unrelated to the drug
• Improvement in intraocular pressure
• Viral keratitis induced by the drug

Correct Answer: Exacerbation of narrow-angle glaucoma due to anticholinergic action

Q26. Compared with quinidine, disopyramide has:

• Stronger anticholinergic effects and greater negative inotropy
• No anticholinergic effects and positive inotropy
• Only beta-blocking properties
• Pure potassium-channel blocking action

Correct Answer: Stronger anticholinergic effects and greater negative inotropy

Q27. Co-administration of disopyramide with which drug class raises concern due to additive negative inotropic effects?

• Beta-blockers
• Topical corticosteroids
• Loop diuretics alone
• Thyroid hormone replacement

Correct Answer: Beta-blockers

Q28. For atrial fibrillation management, disopyramide is generally:

• Less preferred; primarily used for ventricular arrhythmias
• The first-line drug of choice for most AF patients
• Contraindicated in all atrial arrhythmias
• Only used for rate control via AV node blockade

Correct Answer: Less preferred; primarily used for ventricular arrhythmias

Q29. Which constellation of symptoms would most likely reflect disopyramide’s anticholinergic toxicity?

• Blurred vision, dry mouth, constipation
• Excessive sweating, rhinorrhea, salivation
• Hypersalivation, diarrhea, miosis
• Hypotension with excessive lacrimation

Correct Answer: Blurred vision, dry mouth, constipation

Q30. The proarrhythmic mechanism leading to torsades with disopyramide is primarily due to:

• Prolongation of repolarization causing early afterdepolarizations (EADs)
• Excessive shortening of action potential causing re-entry only
• Direct catecholamine release from myocardial stores
• Selective increase in intracardiac conduction velocity

Correct Answer: Prolongation of repolarization causing early afterdepolarizations (EADs)

G S Sachin

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