Anti Arrhythmia Drugs

Question 1

Disopyramide

Answer 1

Na channel blockers – class 1A - oral

• Slow phase 0 depolarization, slow conduction, medium kinetics, prolong action potential
• Negative inotrope – avoid in heart failure
• Ventricular arrhythmias, recurrent atrial arrhythmias

Question 2

Procainamide

Answer 2

Na channel blockers – class 1A – oral or IV

• Extreme prolonging of action potentials (NAPA) – slow phase 0 depolarization, slow conduction, medium kinetics
• Lupus like effects, nausea
• Ventricular arrhythmias, recurrent atrial arrhythmias

Question 3

Quinidine

Answer 3

Na channel blockers – class 1A – oral or IV

• Slow phase 0 depolarization, slow conduction, medium kinetics, prolong action potential
• Diarrhea
• Ventricular arrhythmias, recurrent atrial arrhythmias

Question 4

Lidocaine

Answer 4

Na channel blockers – class 1B - IV

• Slow phase 0 depolarization, slow conduction, fast kinetics, shorten action potential
• CNS toxicity – sedation, slurred speech
• Acute ventricular arrhythmias (common with MI)

Question 5

Mexiletine

Answer 5

Na channel blockers – class 1B - oral

• Slow phase 0 depolarization, slow conduction, fast kinetics, shorten action potential
• CNS toxicity – sedation, slurred speech
• Chronic ventricular arrhythmias

Question 6

Flecainide

Propafenone

Answer 6

Na channel blockers – class 1C - oral

• Slow phase 0 depolarization, slow conduction, slow kinetics, minimal effect on action potential duration
• Arrhythmogenic – can cause arrhythmias in pts with known heart disease
• Recurrent atrial arrhythmias

Question 7

Amiodarone

Answer 7

K channel blockers – oral or IV

• Lengthen AP and effective refractory period, also some Na and Ca channel blocking
• Bradycardia (B-blocking effects) – accumulates in tissues (lipid soluble) and can cause pulmonary, liver, thyroid, eye, and skin toxicities
• Atrial and ventricular arrhythmias, less arrhythmogenic in patients with heart failure or post MI

Question 8

Dofetilide

Answer 8

K channel blockers – oral (start in hospital)

• Lengthen AP and effective refractory period
• Marked QT prolongation (torsade de pointes)
• Atrial arrhythmias

Question 9

Dronedarone

Answer 9

K channel blockers - oral

• Lengthen AP and effective refractory period
• Lack thyroid and pulmonary toxicity of amiodarone
• Atrial and ventricular arrhythmias

Question 10

Ibutilide

Answer 10

K channel blockers – IV (in hospital)

• Lengthen AP and effective refractory period
• Marked QT prolongation (torsade de pointes)
• Acute conversion of atrial fibrillation/flutter

Question 11

Sotalol

Answer 11

K channel blockers – oral (start in hospital)

• Lengthen AP and effective refractory period
• Bradycardia (B-blocking effects of L-isomer), marked QT prolongation (torsade de pointes)
• Atrial and ventricular arrhythmias

Question 12

Adenosine

Answer 12

Anti-arrhythmic – IV short ½ life

• Activates Ik and inhibits Ica mostly on AV node
• Brief asystole, heart block
• Supraventricular tachycardia, Afib, atrial flutter (aids diagnosis)