Anti-Arrhythmics Flashcards
Aims of antiarrythmic therapy (2)
- Reduce ectopic pacemaker activity
- Regularize impulse of conduction pathway
What do class 1 anti-arrythmics do
Membrane stabilizers
- Increase threshold of excitability
- Decrease conduction velocity
- Prolong effective refractory period
- Reduce phase zero of AP
Who are class 1a antiarrythmics? What do they do
- Quinidine sulphate
- Procainamide
Which anti-arrythmic is good for ventricular premature complexes and supra-ventricular tachycardia in large breeds
Quinidine sulphate
Which drug is good for atrial flutter in horses
Quinidine sulphate
What are A/E of quinidine sulphate in horses
- Wheals
- Laminitis
- GI upset
- Nasal mucosa damage
Which Class 1a is best for atrial arrythmias
Quinidine sulphate
Which class 1a is best for ventricular arrythmias
Procainamide
Which class 1a is less vagolytic
Procainamide
Which class 1a has long half-life in dogs
Procainamide
Toxicity of procainamide
Wide QRS
Arrythmias
Hypotension
What do Class-1b drugs do
Reduce conduction velocity in injured cardiac cells
What effects do Class-1b drugs have on AP/RP
minimal effects
Which Class-1b drug is a broad antiarrythmic
Aprindine, Indecainide (more potent)
- Good for dogs that are resistant to others*
- Lots of A/E! –> give as last resort*
Which class-1B is used for cardiac emergencies
Lidocaine - give IV (rapid effect, short half-life)
Class-1b drugs mainly target what kind of arrythmias
Ventricular arrythmias
(except Aprindine/Indecainide which are broad spectrum)
Adverse effects of Aprindine.
- Leukopenia
- Hepatotoxicosis
- Hypotension
- Seizures
- etc…
Whats the difference between Indecainide and Aprindine
Indecainide is more potent and has fewer A/E
Which Class-1b is given for digitalis arrythmias (along with ventricular arrythmias)
Phenytoin