00 Antiarrhythmics

Question 1

What are Class I antiarrhythmics main MOA?

Answer 1

Sodium channel blockers

Question 2

What is Class I divided?

Answer 2

Class Ia (intermediate acting), Class Ib (short acting), Class Ic (long acting)

Question 3

What are the Class Ia drugs?

Answer 3

Disopyramide, Quinidine, Procainamide

Question 4

What are the Class Ib drugs?

Answer 4

Lidocaine, Tocainide, Mexiletine (Phenytoin)

Question 5

What are the Class Ic drugs?

Answer 5

Flecainide, Propafenone, Morizicine

Question 6

Which Class I subgroup has the most ADRs?

Answer 6

Class Ia

Question 7

What are some of the ADRs seen with Class Ia drugs?

Answer 7

Strong antiACh, All agents capable of causing QT prolongation (from blocking K channels) –> TdP, all proarrhythmic

Question 8

Which Class Ia has the most DDIs and can cause Cinchonism?

Answer 8

Quinidine

Question 9

What are Class Ib drugs only useful for?

Answer 9

VENTRICULAR arrhythmias (can’t be used for A.fib)

Question 10

What kind of ADR is seen with Class Ib drugs?

Answer 10

All cross BBB d/t lipophilicity, all have CNS depression ADRs

Question 11

When do you NOT want to use Class Ic drugs?

Answer 11

Do not use in patients with ischemic (CAD) or structural heart disease (LVEF < 40% or severe LVH). Avoid in heart disease!

Question 12

Which Class I subgroup has the least ADRs?

Answer 12

Class Ic

Question 13

What are the Class II Antiarrhythmics?

Answer 13

Beta-Blockers (Metoprolol, Propranolol, Esmolol)

Question 14

What are the Class II Antiarrhythmics mainly used for?

Answer 14

Ventricular rate control and to prevent ventricular arrhythmias

Question 15

What is unique about Esmolol (Class II Antiarrhythmics)?

Answer 15

Ultra short acting, IV only, large fluid volume (comes in big IV bag)

Question 16

How do Class III Antiarrhythmics work?

Answer 16

Prolong refractory period. Blockade of potassium channels

Question 17

What are the Class III Antiarrhythmic drugs?

Answer 17

Amiodarone/Dronedarone. Sotalol. Ibutilide/Dofetilide

Question 18

How is Ibutilide different than the other Antiarrhythmics in Class III?

Answer 18

Instead of blocking potassium channels, it activates inward sodium channels

Question 19

What are the Class IV Antiarrhythmic drugs?

Answer 19

CCBs (Verapamil and Diltiazem)

Question 20

What are Class IV Antiarrhythmic drugs used for?

Answer 20

Slow conduction through AV node, used for ventricular rate control

Question 21

What are the common ADRs with Verapamil?

Answer 21

Constipation/GERD

Question 22

What are some common Antiarrhythmics used that don’t fall into the four classes?

Answer 22

Adenosine. Digoxin. Magnesium

Question 23

What is Magnesium most commonly used for?

Answer 23

Torsades de Pointes

Question 24

What is the DOC for patients with ischemic (CAD) or structural heart disease (LVEF < 40% or severe LVH)?

Answer 24

Amiodarone

Question 25

What is the PK of Amiodarone like?

Answer 25

Slow distribution (need loading dose). Long half-life (60 days parent compound, up to 180 days for desethylamiodarone)

Question 26

What is the PO dosing for Amiodarone like?

Answer 26

LD: 800-1600 mg/day Maintenance: 100-400 mg/day

Question 27

What is the IV dosing for Amiodarone like?

Answer 27

150mg x1, 1mg/min x6h, 0.5mg/min x18h = approx 1g in first day. For life-threatening arrhythmias (ACLS): 300mg IV push

Question 28

What are the most common ADRs with Amiodarone?

Answer 28

Thyroid (hypo/hyper), Pulmonary fibrosis (dose and time dependent, treatment limiting step), Hepatic, GI (take with food), Photosensitivity

Question 29

What looking at AF management, what must you think about?

Answer 29

Always consider the need for the 3 major therapeutic modalities: Ventricular rate control, Anticoagulation, Rhythm conversion/maintenance

Question 30

What type of agents can be selected for Ventricular Rate Control in AF?

Answer 30

Class II and IV (Beta-blocker, CCB (Diltiazem, Verapamil)), Digoxin, Amiodarone (less common)

Question 31

What are the factors looked at for the CHADS2 score?

Answer 31

CHF (1), HTN (1), Age 75+ (1), Diabetes (1), Stroke/TIA (2)

Question 32

How does the CHADS2 score determine anticoagulation needs?

Answer 32

0 = ASA, 1 = ASA or Warfarin/Dabigratran/Rivaroxaban/Apixaban, 2+ = Warfarin/Dabigratran/Rivaroxaban/Apixaban

Question 33

What agents are used for Rhythm CONVERSION?

Answer 33

1a, 1c, III. (II & IV are rate control). Amiodarone DOC for patients with ischemic or structural heart disease (Dronedarone may be first-line for all others). Sotalol DOC for post-MI/CAD w/o structural heart disease

Question 34

What must be monitored when initiating Amiodarone?

Answer 34

Liver function and Pulmonary function

Question 35

What properties does Propafenone have?

Answer 35

Beta-blocker

Question 36

Which agent must be initiated in-hospital with renal function and QT documented?

Answer 36

Dofetilide

Question 37

Make sure you know:

Answer 37

The chart on slide 57