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Flashcards in Anti-arrhythmic drugs Deck (25)
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1

What is a class 1 anti-arrhythmic drug?

A drug that modifies the action potential by acting on the voltage-activated sodium channels

2

How does flecanide work?

Inhibits conduction through His-purkinje system
Suppresses ventricular ectopic beats

3

What subset of class 1 is flecanide?

Class 1 - C

4

In which conditions is flecanide used?

Paroxysmal AF
Ventricular ectopic beats

5

What subset of class 1 is quinidine?

Class 1 - A

6

How do class 1 A drugs work?

Increase the length of the action potential
Increase refractory period
Block sodium channels when they are in the "open" or "active" state
They have some muscarinic effects

7

In what conditions is quinidine used?

AF
Give with digoxin to slow AV conduction and prevent VT

8

How do class 1 B drugs work?

Block sodium channels in "refractory" state
Shortens action potential
Lengthens refractory period

9

Give an example of a class 1 B drug.

Lignocaine

10

Which conditions is lignocaine used in?

Useful in cells affected by ischemia - used in patients post MI, particularly effective in prevention of arrhythmias such as VT

11

What type of drugs are class 2 anti-arrhythmic drugs?

Beta blockers

12

How do class 2 anti-arrhythmic drugs work?

Counteract elevated sympathetic activity
Increase refractory period of SA node
Decrease SA & AV activity

13

What arrhythmias are beta blockers used to treat?

Used in the prevention of paroxysmal attacks of AF

14

Give two examples of class 3 drugs.

Amiodarone
Sotalol

15

How do class 3 anti-arrhythmics work?

They substantially prolong the action potential by blocking voltage-activated potassium channels
This also increases refractory period

16

What effect does increased action potential and refractory period have?

Interrupts re-entrant tachycardia
Suppresses ectopic activity

17

What is amiodarone used to treat?

VT & SVTs
Tachycardia associated with WPW

18

What is sotalol used to treat?

It can prevent short runs of VT
Used in paroxysmal SVTs e.g. AF

19

What side effects can amiodarone cause?

Blue/slate grey skin
Thyroid abnormalities
Pulmonary fibrosis

20

What type of drugs are class 4 anti-arrhythmic drugs?

Calcium channel antagonists

21

Which class 4 anti-arrhythmic is the drug of choice and why?

Verapamil - selective for cardiac calcium channels

22

How do class 4 anti-arrhythmic drugs work?

Slows SA & AV conduction

23

In which condition is the use of verapamil contraindicated?

In conjuction with beta-blockers
In Wolf-Parkinson-White syndrome

24

Which drug is also important in the treatment of arrhythmias that does not belong to any class?

Adenosine

25

What is adenosine used for?

Tachycardias