EXAM #1: ANTIARRHYTHMIC PHARMACOTHERAPY

Question 1

What are Class I antiarrhythmics?

Answer 1

Na+ Blockers

Question 2

What are Class II antiarrhythmics?

Answer 2

Beta Blockers

Question 3

What are Class III antiarrhythmics?

Answer 3

K+ Blockers

Question 4

What are Class IV antiarrhythmics?

Answer 4

Ca++ Blockers

Question 5

What are the class IA drugs?

Answer 5

Quinidine
Procainamide
Disopyramide

Question 6

What are the class IB drugs?

Answer 6

Lidocaine

Mexiletine

Question 7

What are the class IC drugs?

Answer 7

Flecainide

Propafenone

Question 8

Generally, what do you need to remember about IB vs IC drugs antiarrhythmics?

Answer 8

B is Best post-MI, C is Contraindicated post-MI

Question 9

Why have the class IA drugs most faded from clinical use?

Answer 9

• Association with INCREASED MORTALITY in atrial arrhythmia
• QT prolongation is arrhythmiogenic (Torsades)
• Induces G6PD hemolytic anemia

Question 10

How was Quinidine used in clinical practice?

Answer 10

Both atrial and ventricular arrhythmias, esp.

• Re-entrant SVT
• VT

Question 11

What was the previous use of procainamide?

Answer 11

2nd line in ACLS algorithm (2014) for VT/VF

Question 12

What toxicity is specifically associated with procainamide?

Answer 12

SLE-like syndrome

Question 13

What metabolite is associated with procainamide toxicity?

Answer 13

NAPA–polymorphisms can lead to differential toxicity

Question 14

What is the specific toxicity associated disopyramide?

Answer 14

Heart failure

*Also, anticholingeric effects i.e. dry mouth, urinary retention, constipation…etc.

Question 15

What type of local anesthetic is lidocaine?

Answer 15

Amide

Question 16

What is lidocaine specifically indicated for?

Answer 16

Ventricular arrhythmias especially post-MI

Note that it has been entirely replaced by Amiodarone in 2016 ACLS guidelines

Question 17

What toxicities are associated with Lidocaine?

Answer 17

CNS stimulation/depression

Question 18

Can you take lidocaine with a hx of allergy to procaine?

Answer 18

Yes, procaine is an ESTER

Question 19

What is Flecainide indicated for?

Answer 19

First line agent for atrial arrhythmias WITHOUT IHD

Question 20

When is Flecainide contraindicated?

Answer 20

Remember, Class IC is Contraindicated in patients with structural or IHD (esp. post MI)

Question 21

What are the clinical indications for Propafenone?

Answer 21

Class IC–same as Flecainide i.e. first line for a-fib

Question 22

What adverse effects are associated with Class IC drugs?

Answer 22

Proarrhythmic i.e. QT prolongation and Torsades

Question 23

What do you need to remember about Class I drugs and CHF?

Answer 23

Increased mortality of Class I (all) in CHF

Question 24

What positive effect is associated B-Blocker use in arrhythmias?

Answer 24

Decreased mortality in ventricular arrhythmias

Question 25

What receptors does Sotalol have an effect on?

Answer 25

K+ and Beta

Question 26

What is Sotalol commonly indicated for?

Answer 26

A-fib WITH IHD

Question 27

What are the major side effects associated with Sotalol?

Answer 27

1) Torsades (one of the most dangerous drugs associated with QT prolongation and drug induced Torsades) 2) Excessive Beta-blockade *So bad that you're really supposed to start the drug in the hospital*

Question 28

What is Amiodarone the first line agent for?

Answer 28

VT/VF

Question 29

Why is Amiodarone so important?

Answer 29

Class III but has effects in all classes; thus, it is efficacious in the treatment of almost any arrhythmia

Question 30

What are the major side effects associated with Amiodarone? What do you have to do when you prescribe this drug?

Answer 30

1) Pulmonary fibrosis (chronic use) 2) Hepatotoxicity 3) Hypothyroidism Thus, check PFTs, LFTs, and TFTs 4) Corneal deposits (annual fundoscopic exam) 5) Blue/grey skin deposits and photosensitivity 6) Neurologic effects--fine intention tremor

Question 31

What is the half-life of Amiodarone?

Answer 31

2 months--related to its high Vd

Question 32

What drugs do you need especially conscious of when prescribing Amiodarone?

Answer 32

Warfarin and digoxin

Question 33

What is Dronaderone?

Answer 33

Amiodarone without iodine--much safer than amiodarone but not as effective

Question 34

When is Dronaderone contraindicated?

Answer 34

CHF--increased mortality

Question 35

What is Dofetilide indicated for?

Answer 35

A-fib (both acute and chronic)

Question 36

What toxicity is associated with Dofetilide?

Answer 36

Torsades de Points (worse than Sotalol) *This drug has the highest incidence of Torsades of ANY drug--requires 3 day admission for monitoring*

Question 37

How are ventricular arrhythmias commonly treated?

Answer 37

ICD

Question 38

What is the general treatment approach for A-fib?

Answer 38

1) Shock | 2) Drugs

Question 39

What is the difference between rhythm and rate control for a-fib?

Answer 39

Rhythm= - Flecainide or Propafeneone (NO IHD) vs. - Sotalol/ Amiodarone (IHD/CHF) Rate= Beta-blockers, diltiazem, digoxin