Class 3 Anti-arrhythmics

Question 1

Class 3 Anti-arrhythmics are also known as what?

Answer 1

K+ channel blockers

Question 2

Name 3 Class 3 anti-arrhythmic drugs.

Answer 2

1. Bretylium
2. Amiodarone
3. Sotalol (also a non-selective beta blocker)

Question 3

The bad thing about Class 3 anti-arrhythmics is that they tend to be very ______.

Answer 3

TOXIC

Question 4

Class 3 anti-arrhythmics tend to be reserved for what?

Answer 4

Refractory tachyarrhythmias (Say you use Lidocaine and it doesn’t work, you might want to reach for a Class 3 drug. Caution advised however because these drugs are very toxic. Should refer to cardiologist!)

Question 5

To maintain dogs with supraventricular premature depolarizations or supraventricular tachycardia, you could use which Class 3 drug?

Answer 5

Sotalol + Diltiazam

Question 6

When treating VPC’s in dogs and cats is a Class 3 drug an option?

Answer 6

Yes in dogs you’d use Esmolol IV + Sotalol/Propranolol. In cats you’d use either Sotalol or Amiodarone possibly if other options didn’t work first.

Question 7

In dogs with a-fib where the heart function is decreased and the rate is up to slow the ventricular response rate you could use a beta blocker + diltiazam & digoxin OR you could use….

Answer 7

Amiodarone and attempt cardioversion