Antiarrhythmic Drugs Flashcards

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Questions and Answers

What type of drug is Metoprolol?

Class II Antiarrhythmic - Beta-Blocker.

What type of drug is Propranolol?

Class II Antiarrhythmic - Beta-Blocker.

What type of drug is Esmolol?

Class II Antiarrhythmic - Beta-Blocker. Very short acting.

What type of drug is Atenolol?

Class II Antiarrhythmic - Beta-Blocker. Signup and view all the answers

What type of drug is Timolol?

Class II Antiarrhythmic - Beta-Blocker. Signup and view all the answers

What type of drug is Carvedilol?

Class II Antiarrhythmic - Beta-Blocker. Signup and view all the answers

What is the mechanism of action for Class II Antiarrhythmics?

Decrease SA and AV nodal activity by decreasing cAMP, and decreasing Ca2+ currents (decrease automaticity). Suppress abnormal pacemakers by decreasing slope of phase 4 (prevent triggered arrhythmias). AV node particularly sensitive, causing increased PR interval (increase effective refractory period of the AV node). Signup and view all the answers

What is the clinical use for Class II Antiarrhythmics?

SVT, slowing ventricular rate during a-fib and atrial flutter, atrial or ventricular premature beats, ventricular tachycardia. Signup and view all the answers

What is the toxicity associated with Class II Antiarrhythmics?

Impotence, exacerbation of COPD and asthma, cardiovascular effects (bradycardia, AV block, CHF), CNS effects (sedation, sleep alterations), may mask the signs of hypoglycemia. Signup and view all the answers

What is the toxicity associated with Metoprolol and Propranolol?

Dyslipidemia (Metoprolol), can exacerbate vasospasm in Prinzmetal angina (Propranolol), contraindicated in cocaine users (risk of unopposed alpha-adrenergic receptor agonist activity). Treat overdose with glucagon. Signup and view all the answers

What type of drug is Amiodarone?

Class III Antiarrhythmic - K+ channel blockers. Signup and view all the answers

What type of drug is Ibutilide?

Class III Antiarrhythmic - K+ channel blockers. Signup and view all the answers

What type of drug is Dofetilide?

Class III Antiarrhythmic - K+ channel blockers. Signup and view all the answers

What type of drug is Sotalol?

Class III Antiarrhythmic - K+ channel blockers. Signup and view all the answers

What is the mechanism of action for Class III Antiarrhythmics?

Increase AP duration in Purkinje and ventricular muscle fibers by blocking outward K+ current of phase 3 repolarization. Increase Effective Refractory Periods (ERP). Used when other antiarrhythmics fail. Increases QT interval. Signup and view all the answers

What are the clinical uses for Class III Antiarrhythmics?

Atrial fibrillation, atrial flutter, ventricular tachycardia (Amiodarone, Sotalol), bypass tract-mediated PSVT. Signup and view all the answers

What is the toxicity associated with Sotalol and Ibutilide?

Torsades de pointes (Both), excessive beta-blockade (Sotalol). Signup and view all the answers

What is the toxicity associated with Amiodarone?

Pulmonary fibrosis, hepatotoxicity, hypothyroidism/hyperthyroidism (Amiodarone is 40% iodine by weight), corneal deposition, skin deposits (blue/gray) resulting in photodermatitis, neurologic effects, constipation, cardiovascular effects (bradycardia, heart block, CHF). Signup and view all the answers

What special considerations must be made when using Amiodarone?

Remember to check PFTs, LFTs, and TFTs when using Amiodarone. Amiodarone has class I, II, III, and IV effects and alters the lipid membrane. Signup and view all the answers

What type of drug is Verapamil?

Class IV Antiarrhythmic - Ca2+ Channel Blockers. Signup and view all the answers

What type of drug is Diltiazem?

Class IV Antiarrhythmic - Ca2+ Channel Blockers. Signup and view all the answers

What is the mechanism of action for Class IV Antiarrhythmic Drugs?

Within nodal tissue, calcium channel blockade decreases the rate of rise of phase 0 depolarization and conduction velocity (decrease reentry). Increase Effective Refractory Periods (ERP) of the AV node. Raise threshold potential at the SA node (decrease HR). Increase PR interval. Signup and view all the answers

What are the clinical uses for Class IV Antiarrhythmic Drugs?

Prevention of nodal arrhythmias (e.g. PSVT), atrial fibrillation and flutter (decreases ventricular rate), multifocal atrial tachycardia (decreases ventricular rate). Signup and view all the answers

Study Notes

Class II Antiarrhythmic Drugs

Metoprolol, Propranolol, Esmolol, Atenolol, Timolol, and Carvedilol are all classified as Class II Antiarrhythmics, specifically beta-blockers.
Esmolol is noted for its very short acting properties.
Mechanism of action involves decreasing SA and AV nodal activity, reducing cAMP, which lowers Ca2+ currents, thereby decreasing automaticity and suppressing abnormal pacemakers.
Clinical applications include treating supraventricular tachycardia (SVT), controlling ventricular rate in atrial fibrillation and flutter, and managing premature beats or ventricular tachycardia.
Common toxicities include impotence, exacerbation of COPD/asthma, cardiovascular issues (bradycardia, AV block, CHF), CNS effects (sedation, sleep alterations), and masking hypoglycemia signs.
Specific toxicities: Metoprolol can cause dyslipidemia, while Propranolol may exacerbate Prinzmetal angina and is contraindicated in cocaine users.

Class III Antiarrhythmic Drugs

Amiodarone, Ibutilide, Dofetilide, and Sotalol are classified as Class III Antiarrhythmics and function as K+ channel blockers.
Class III drugs increase action potential duration in Purkinje and ventricular muscle fibers by blocking K+ currents during phase 3 repolarization and raise effective refractory periods.
Clinical uses involve treating atrial fibrillation, atrial flutter, and ventricular tachycardia; they are particularly valuable when other antiarrhythmics fail.
Sotalol and Ibutilide can lead to torsades de pointes, with Sotalol also causing excessive beta-blockade.
Amiodarone's toxicities include pulmonary fibrosis, hepatotoxicity, thyroid dysfunctions, corneal deposition, skin deposits causing photodermatitis, neurologic effects, constipation, and cardiovascular issues.

Special Considerations for Amiodarone

Requires monitoring of pulmonary function tests (PFTs), liver function tests (LFTs), and thyroid function tests (TFTs).
Notable for having combined effects characteristic of Class I, II, III, and IV drugs and alters the lipid membrane.

Class IV Antiarrhythmic Drugs

Verapamil and Diltiazem are classified as Class IV Antiarrhythmics, functioning as calcium channel blockers.
They decrease the rate of rise of phase 0 depolarization and conduction velocity in nodal tissue, which helps reduce reentry mechanisms.
Clinical applications include prevention of nodal arrhythmias (like PSVT), controlling ventricular rates in atrial fibrillation and flutter, and managing multifocal atrial tachycardia.
Class IV drugs increase effective refractory periods in the AV node and prolong the PR interval.

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Explore key concepts about Class II, III, IV, and other antiarrhythmic drugs through this flashcard quiz. Test your knowledge on specific medications such as Metoprolol, Propranolol, and Esmolol. Perfect for medical students and healthcare professionals!