Class IC Flashcards
What three drugs are Class IC?
- Flecainide
- Propafenone
- Moricizine
What is the mechanism of drugs in class IC?
- Significantly prolongs refractory period in AV node
- Minimal effect on AP duration
What are the cardiac effects of Flecainide?
- Slows upstroke of AP
- Slows conduction
- Potent Na+ and K+ channel blocker
- Slow unblocking kinetics (but does not prolong AP or QT)
What are the cardiac effects of Propafenone?
- Slows upstroke of AP
- Slows conduction
- Weak beta blocking activity
- Similar to quinidine w/out AP prolongation
What are the cardiac effects of Moricizine?
-Inhibits rapid inward Na+ current in myocardial cells
What are the extra cardiac effects of Flecainide?
None
What are the extra cardiac effects of Propafenone?
Bradycardia and bronchospasm (beta blocker)
What are the extra cardiac effects of Moricizine?
None
What are the pharmacokinetics of Flecainide?
- Rapidly and completely absorbed via GI
- Peak plasma concentration @ 2-3 hours
- No significant first pass metabolism
What are the pharmacokinetics of Propafenone?
- Rapidly and completely absorbed via GI
- Extensive first pass metabolism via hydroxylation (CYP2D6)
What are the pharmacokinetics of Moricizine?
-Significant 1st pass metabolism by liver
What toxicity is associated with Flecainide?
- Potential for new/more severe arrhythmias
- Potential to exacerbate CHF, especially in those with Cardiomyopathy or CHF
What toxicity is associated with Propafenone?
- New or worsened CHF in patients w/HF or decreased EF
- Possible reversible granulocytopenia or agranulocytosis
- Inhibition of bronchodilation (Beta blocker) –> not recommended for those w/asthma
What toxicity is associated with Moricizine?
-Vomiting, LOC, severe hypotension
What are the therapeutic uses for Flecainide?
- Suppression and prevention of recurrent life threatening arrhythmias
- Prevention of paroxysmal supraventricular tachycardias (AV nodal reentrant tachycardia & Wolff-Parkinson-White syndrome)
