Anti-Arrhythmic (Drugs)

Question 1

Procainamide

Answer 1

Class IA - Sodium Channel Blocker
- Treats Arrhythmia

MOA:
- Blocks NA+ channels
–> Decrease Phase 0 Depolarization
–> Slows conduction velocity
–> Also prolongs repolarization

Moderate Effect
- Medium Association/Dissociation

Question 2

Lidocaine

Answer 2

Class IB - Sodium Channel Blocker
- Treats Arrhythmia

MOA:
- Blocks NA+ channels
–> Decrease Phase 0 Depolarization
–> Slows conduction velocity

Weak Effect
- Fast Association/Dissociation

Question 3

Propafenone

Answer 3

Class IC - Sodium Channel Blocker
- Treats Arrhythmia

MOA:
- Blocks NA+ channels
–> Decrease Phase 0 Depolarization
–> Slows conduction velocity

Fast Effect
- Slow Association/Dissociation

Question 4

Flecainide

Answer 4

Class IC - Sodium Channel Blocker
- Treats Arrhythmia

MOA:
- Blocks NA+ channels
–> Decrease Phase 0 Depolarization
–> Slows conduction velocity

Strong Effect
- Slow Association/Dissociation

Question 5

Nadolol, Pindolol, Timolol, Propranolol

Answer 5

Class 2 - 1st Generation Beta-Blocker
(Non-Selective Beta 1 and 2)

MOA:
- Pacemaker Cells
–> Slows pacemaker potential
–> Decrease repolarization
- Contractile Cells:
–> Lowers Calcium and Contraction Force
= Lowers HR

Flat Dose-Reponses Curve
- High doses will only cause more problems

Question 6

Bisoprolol, Esmolol, Acebutolol, Atenolol, Metoprolol

Answer 6

Class 2 - 2nd Generation Beta-Blocker
(Selective Beta 1)

MOA:
- Pacemaker Cells
–> Slows pacemaker potential
–> Decrease repolarization
- Contractile Cells:
–> Lowers Calcium and Contraction Force
= Lowers HR

Flat Dose-Reponses Curve
- High doses will only cause more problems

Question 7

Amiodarone

Answer 7

Class III - Potassium Channel Blockers

MOA:
- Delays repolarization, increases refractory period
- Works better at low HR, prevents Afib

Adverse:
- Pulmonary Fibrosis (Inhibits CYP2C9)

Question 8

Dronedarone

Answer 8

Class III - Potassium Channel Blockers

MOA:
- Delays repolarization, increases refractory period
- Works better at low HR, prevents Afib

Adverse:
- No iodine, Less adverse effects than Amiodarone
- Not as effective

Question 9

Sotalol

Answer 9

Class III - Potassium Channel Blockers

MOA:
- Delays repolarization, increases refractory period
- Works better at low HR, prevents Afib

• Blocks bAR
• Works better at low HR, prevents Afib

Question 10

Dofetilide

Answer 10

Class III - Potassium Channel Blockers

MOA:
- Delays repolarization, increases refractory period
- Works better at low HR, prevents Afib

Adverse:
- Likely to cause arrhythmia

Question 11

Ibutilide

Answer 11

Class III - Potassium Channel Blockers

MOA:
- Delays repolarization, increases refractory period
- Works better at low HR, prevents Afib

Adverse:
- Likely to cause arrhythmia

Question 12

Nifedipine

Answer 12

Dihydropine - Calcium Channel Blocker

MOA:
Focuses on Arterial Blood Vessels (Vasculature)
- Vasodilation
- Reduce Peripheral Vascular Resistance

Question 13

Verapamil

Answer 13

Class IV - Calcium Channel Blocker
- Non-Dihydropyridine

MOA:
- Binds to high frequency Ca2+ Channels (Heart)
–> Decreases Cardiac Contractility
–> Decreases Heart Rate

Question 14

Diltiazem

Answer 14

Class IV - Calcium Channel Blocker
- Non-Dihydropyridine

MOA:
- Binds to high frequency Ca2+ Channels (Heart)
–> Decreases Cardiac Contractility
–> Decreases Heart Rate

Question 15

Digoxin

Answer 15

Treats Heart Failure and Arrhythmia

MOA:
- Inhibits Na+/K+ ATPase Pump
–> Increased Intracellular Na+, which is then cotransported with Ca2+
–> Increases Intracellular Ca2+
–> Increases Ionotropic Action

Question 16

Adenosine

Answer 16

Treats Reentry Conduction - Targets A1 Receptors (GPCR, Gs)
- Decreases HR and reduces Conduction Velocity

MOA:
Cardiac Cells:
- Decreases cAMP –> Inhibits LTCC
–> Slows conduction velocity
Pacemaker Cells:
- Inhibits funny Ca2+ Channels
–> Decreases Phase 4 firing rate

Question 17

Magnesium Sulphate

Answer 17

Treats Arrhythmia
- Important in transporting Na+, K+, Ca2+ across cell membrane

MOA:
- Unknown