Antiarrhythmic drugs MCQs With Answer provides B. Pharm students a focused, practical review of antiarrhythmic pharmacology, mechanisms, and clinical considerations. This set emphasizes key concepts such as Vaughan-Williams classification, mechanism of action, electrophysiologic effects on cardiac action potentials, pharmacokinetics, therapeutic monitoring, common adverse effects, proarrhythmia, and drug–drug interactions (including CYP-mediated interactions and QT prolongation). Designed to deepen understanding beyond superficial facts, these MCQs cover drug-specific profiles (e.g., amiodarone, lidocaine, flecainide, sotalol), indications for supraventricular versus ventricular arrhythmias, dosing concerns, and safety monitoring relevant to pharmacy practice.
‘Now let’s test your knowledge with 30 MCQs on this topic.’
Q1. Which class of antiarrhythmic drugs primarily blocks fast sodium channels and slows phase 0 depolarization?
- Class I antiarrhythmics
- Class II beta blockers
- Class III potassium channel blockers
- Class IV calcium channel blockers
Correct Answer: Class I antiarrhythmics
Q2. In the Vaughan-Williams classification, which subclass preferentially shortens action potential duration and is used for ventricular arrhythmias?
- Class IA
- Class IB
- Class IC
- Class III
Correct Answer: Class IB
Q3. Which antiarrhythmic drug is well known for causing pulmonary fibrosis, thyroid dysfunction, and a very long half-life?
- Procainamide
- Amiodarone
- Flecainide
- Verapamil
Correct Answer: Amiodarone
Q4. Which drug is a Class IC agent indicated for life-threatening ventricular arrhythmias but is contraindicated in structural heart disease?
- Lidocaine
- Flecainide
- Sotalol
- Quinidine
Correct Answer: Flecainide
Q5. Which antiarrhythmic is a pure beta-blocker with class II properties and can also prolong AV nodal conduction to treat supraventricular tachycardia?
- Propranolol
- Amiodarone
- Procainamide
- Disopyramide
Correct Answer: Propranolol
Q6. Which drug is a Class III agent that blocks potassium channels and may cause torsades de pointes by prolonging the QT interval?
- Sotalol
- Lidocaine
- Metoprolol
- Digoxin
Correct Answer: Sotalol
Q7. Which antiarrhythmic is commonly used intravenously for acute ventricular arrhythmias and preferentially affects ischemic tissue with rapid onset and short duration?
- Lidocaine
- Amiodarone
- Quinidine
- Verapamil
Correct Answer: Lidocaine
Q8. Which adverse effect is most characteristically associated with procainamide during prolonged therapy?
- Blue-gray skin discoloration
- Drug-induced lupus-like syndrome
- Bronchospasm
- Hyperthyroidism
Correct Answer: Drug-induced lupus-like syndrome
Q9. Which electrophysiologic phase is primarily affected by Class IV (verapamil, diltiazem) antiarrhythmics?
- Phase 0 (rapid depolarization)
- Phase 1 (initial repolarization)
- Phase 2 (plateau)
- Phase 4 (diastolic depolarization / AV nodal conduction)
Correct Answer: Phase 4 (diastolic depolarization / AV nodal conduction)
Q10. Which antiarrhythmic has significant anticholinergic side effects and negative inotropic effects, making it risky in elderly patients with heart failure?
- Disopyramide
- Amiodarone
- Lidocaine
- Propranolol
Correct Answer: Disopyramide
Q11. Which drug interaction is most important when prescribing amiodarone with warfarin?
- Amiodarone decreases warfarin levels via induction of CYP enzymes
- Amiodarone inhibits CYP enzymes increasing warfarin levels and bleeding risk
- Amiodarone has no interaction with warfarin
- Amiodarone increases warfarin renal excretion
Correct Answer: Amiodarone inhibits CYP enzymes increasing warfarin levels and bleeding risk
Q12. Which antiarrhythmic is contraindicated in patients with Wolff–Parkinson–White syndrome and atrial fibrillation with an accessory pathway due to risk of accelerating ventricular response?
- Amiodarone
- Verapamil
- Procainamide
- Flecainide
Correct Answer: Verapamil
Q13. Which Class IA drug commonly prolongs the QT interval and can cause cinchonism (tinnitus, headache, hearing loss)?
- Quinidine
- Lidocaine
- Metoprolol
- Amiodarone
Correct Answer: Quinidine
Q14. Which monitoring parameter is essential when a patient is started on sotalol?
- Serum potassium only
- Baseline and serial ECG for QT interval and renal function
- Thyroid function tests
- Pulmonary function tests
Correct Answer: Baseline and serial ECG for QT interval and renal function
Q15. Which antiarrhythmic mechanism best describes digoxin’s effect on arrhythmias?
- Class I sodium channel blockade
- Enhanced vagal tone and decreased AV nodal conduction
- Potassium channel blockade prolonging repolarization
- Direct beta-adrenergic blockade
Correct Answer: Enhanced vagal tone and decreased AV nodal conduction
Q16. Which electrolyte disturbance increases the risk of digitalis toxicity and may enhance arrhythmogenic effects?
- Hyperkalemia
- Hypokalemia
- Hypermagnesemia
- Hypercalcemia
Correct Answer: Hypokalemia
Q17. Which antiarrhythmic is known for significant first-pass metabolism with variable oral bioavailability, and its oral dose must be individualized?
- Flecainide
- Amiodarone
- Procainamide
- Lidocaine
Correct Answer: Flecainide
Q18. Which drug is preferred for acute management of torsades de pointes associated with prolonged QT interval?
- Intravenous magnesium sulfate
- Intravenous lidocaine
- Oral amiodarone
- Intravenous beta-blocker
Correct Answer: Intravenous magnesium sulfate
Q19. Which Class III antiarrhythmic also has beta-blocking properties and is renally excreted, requiring dose adjustment in renal impairment?
- Amiodarone
- Sotalol
- Dofetilide
- Ibutilide
Correct Answer: Sotalol
Q20. Which antiarrhythmic’s active metabolite (N-acetylprocainamide, NAPA) has Class III activity leading to prolonged QT and risk of torsades?
- Procainamide
- Quinidine
- Flecainide
- Lidocaine
Correct Answer: Procainamide
Q21. Which principle is most important when using Class IC agents such as propafenone or flecainide?
- They are safe in structural heart disease including post-MI patients
- They can exacerbate ventricular arrhythmias in patients with ischemic heart disease and structural heart disease
- They primarily shorten QT interval and are protective against torsades
- They have strong diuretic effects and reduce preload
Correct Answer: They can exacerbate ventricular arrhythmias in patients with ischemic heart disease and structural heart disease
Q22. Which antiarrhythmic is often used orally for long-term maintenance of rhythm in atrial fibrillation and requires monitoring of thyroid and liver function?
- Lidocaine
- Amiodarone
- Procainamide
- Mexiletine
Correct Answer: Amiodarone
Q23. Which medication is a Class IB antiarrhythmic available orally as mexiletine for chronic therapy of ventricular arrhythmias?
- Methyldopa
- Mexiletine
- Metoprolol
- Milrinone
Correct Answer: Mexiletine
Q24. Which antiarrhythmic effect on action potential duration is typical of Class IA drugs (e.g., procainamide, quinidine)?
- No change in AP duration
- Shortening of AP duration
- Prolongation of AP duration and QT interval
- Only decreased automaticity without AP changes
Correct Answer: Prolongation of AP duration and QT interval
Q25. Which of the following is an important counseling point for patients on amiodarone?
- Avoid grapefruit juice because it induces amiodarone metabolism
- Regular monitoring of thyroid, liver, and pulmonary function is required
- No drug interactions are expected so monitoring is unnecessary
- It is contraindicated with all statins due to severe hyperlipidemia
Correct Answer: Regular monitoring of thyroid, liver, and pulmonary function is required
Q26. Which antiarrhythmic is primarily useful for rate control in acute supraventricular tachycardia by enhancing AV nodal refractoriness and is contraindicated in WPW with pre-excitation?
- Digoxin
- Verapamil
- Procainamide
- Quinidine
Correct Answer: Verapamil
Q27. Which laboratory test is most relevant when a patient on sotalol develops fatigue and dizziness after dose escalation?
- Serum magnesium only
- Electrolytes and ECG to assess QT interval and potassium
- Thyroid function tests
- Liver function tests
Correct Answer: Electrolytes and ECG to assess QT interval and potassium
Q28. Which antiarrhythmic is associated with a risk of agranulocytosis and is monitored with complete blood counts during therapy?
- Procainamide
- Amiodarone
- Flecainide
- Sotalol
Correct Answer: Procainamide
Q29. Which mechanism best explains Class III drugs’ antiarrhythmic action?
- Blockade of fast sodium channels during phase 0
- Blockade of delayed rectifier potassium channels, prolonging repolarization (phase 3)
- Enhancement of L-type calcium current during phase 2
- Stimulation of sympathetic beta receptors to slow conduction
Correct Answer: Blockade of delayed rectifier potassium channels, prolonging repolarization (phase 3)
Q30. When choosing an antiarrhythmic for a patient with heart failure and reduced ejection fraction, which statement is most appropriate?
- Class IC agents are first-line due to safety in heart failure
- Many Class I agents are avoided; amiodarone is often preferred for rhythm control when necessary
- Disopyramide is the agent of choice for severe heart failure
- Sotalol should always be used without monitoring because it is safe in heart failure
Correct Answer: Many Class I agents are avoided; amiodarone is often preferred for rhythm control when necessary
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