B&B Antiarrhythmic Drugs Flashcards
What are the two class 1a antiarrhythmics?
- Quinidine 2. Procainamide “The Queen has Proclaimed that she’s #1a”
What are the two class 1b antiarrhythmics?
- Lidocaine 2. Mexiletine “I’m not going to Lidoyou about my trip to Mexico, which is why I got a b”
What are the two class 1c antiarrhythmics?
- Flecainide 2. Propafenone “1citizen Cain is a Propa gentleman”
What general category are class 2 antiarrhythmics?
B-blockers
What are the 2 class 4 antiarrhythmics?
Block Calcium channels: 1. Verapamil 2. Diltiazem
Class 1 drugs block
Sodium channels
Class 2 drugs block
Betas
Class 3 drugs block
K+ channels
Class 4 drugs block
Ca+2 channels
Use of antiarrhythmic drugs
Only in dangerous and recurrent arrhythmias. Vtach and Afib that won’t go away.
Which antiarrhythmic drugs act on this action potential?
Class I, III (block Na+ channels)- act on ventricular myocytes
Which antiarrhythmic drugs act on this action potential?
Class II, IV antiarrhythmics. Sinus and AV node action potentials (Ca+2 and B-blockers)
Procainamide side effects
Drug-induced lupus
ANA
Anti-histone
When are the 1b drugs useful?
Ischemia
How does Lidocaine terminate arrhythmias?
It abolishes the re-entry circuit
What’s a sign of toxicity in Mexiletine?
Tremor
CAST trial findings
Tested the suppression of arrhythmias hypothesis. Treated patients with 1c drugs. Less arrhythmias but increased risk of arrhythmic death (the ones they had were more deadly). Resulted in a dramatic reduction in use of antiarrhythmics in general.
Can you use 1c drugs in patients with heart structural abnormalities?
NO!
T/F: all class 1 drugs have some use-dependence?
True
What’s a concern for patients on 1c’s in relation to use dependence
Toxicity at heart rates because more binding at high heart rates
What can QT prolongation from Ia and III drugs turn into?
Torsades de Pointes
Results in cardiac arrest
Amiodarone 3 facts:
- Iodine- thyroid
- Sun sensitivity
- Safer than others
