How to treat arrythmias Flashcards
1
Q
What do Class 1 drugs do?
A
Block Sodium channels
They are membrane stabilising agents which means they block the propagation of an action potential
2
Q
Class 1a drugs
A
- They are moderate sodium channel blockers
- They delay the time of repolarasation
- They increase the time for propagation of an A.P.
- used for all arrhythmias
3
Q
Main class 1a drug to know
A
Disopyramide, quinidine
4
Q
Class 1B drugs
A
- they are slow sodium channel blockers
- they increase the time of repolarisation
- they decrease the time of a.p. propagation
- used for ventricular arrythmias
5
Q
Main class 1B drugs (2)
A
Lidocaine
Phenytoin
6
Q
Class 1c drugs
A
- Fast sodium channel blockers
- have little effect on the time of repolarisation
- used for severe ventricular arrhythmias
- used for atrial arrhythmias
7
Q
Main 1c drug?
A
Flecainide
8
Q
Class 2 drugs
A
- decrease the effect of the sympathetic system- therefore decrease the number of impulses sent to the heart-reduce HR
- used for the treatment of supraventricular, ventricular arrhythmias
- first line of treatment for AF
9
Q
main class 2 drugs
A
beta blockers such a bisoprolol and atenolol
bisoprolol now used as first line against atrial fibrillation
10
Q
class 3 drugs
A
increases repolarisation time
blocks K+/ca 2+ channels
11
Q
main class 3 drug?
A
Amiodarone
Sotalo
12
Q
Class 4 drugs
A
Calcium channel blocker
Slow down depolarisation
13
Q
main class 4 drug
A
verapamil
14
Q
Digoxin
A
- Cardiac glucoside: inhibits the sodium- potassium pump
- This alters the normal function of the sodium- channel pump so more calcium is available inside the cell for contraction
- Improves the strength of cardiac contraction= +ve ionotrope
- used for HF and AF
- need to monitor potassium levels in the elderly as digoxin has high toxicity levels
15
Q
Digoxin toxicity levels
A
- used in the elderly : has a low GFR filtration so most of it is excreted
- however it does have a long half life of 36-48 hours which makes it prone to high toxicity levels
- side effects: nausea, vomiting, bradycardia, tachycardia, Xanthopsia (colour blindness)
- how to treat toxicity: add DIGIBAND- binds to digoxin and is excreted in urine
