Pharmacology of Antiarrhythmics Flashcards
Drugs that block these ion channels decrease the excitability of nodal cells.
Ca2+ channel blockers
Class IA antiarrhythmics have a moderate affinity for Na+ channels. What drugs belong to this class?
Quinidine, procainaminde, disopyramide
These Class II anti-arrhythmics are used in acute management of atrial flutter and fibrillation.
Metropolol, esmolol
True/False. Lidocaine is orally effective.
False - Lidocaine must be administered via IV. Mexiletine is orally active
What Na+ channel blockers are used to treat supraventricular tachycardia and atrial fibrillation?
Flecainide, Propafenone
This anti-arrhythmic is first-line for treatment of ventricular tachycardia and fibrillation.
Amiodarone
What is the MOA of Class I antiarrhythmics?
Na+ channel blockers
This anti-arrhythmic is approved for pediatric use.
Sotalol (Class III) - non-selective beta blocker that also blocks K+ channels
What is the antiarrhythmic class for Ca2+ channel blockers?
Class IV
Class IC antiarrhythmics have a high affinity for Na+ channels. What drugs belong to this class?
Flexainide, propafenone
Cardiac tissue is resistant to action potential summation and tetany. Why is this?
Na+ channels in cardiac tissue have open, closed, and inactivated states. In the inactivated state, the channel cannot open regardless of stimulus. This creates an absolute refractory period that prevents tetany.
Influx of what ion through what channels is responsible for cardiac depolarization?
Influx of Ca2+ thru funny channels
Lupus-like autoimmune syndrome is an ADR associated with what antiarrhythmic?
Procainamide
This Class II anti-arrhythmic is used post MI to prevent arrhythmias.
Propanolol
What is the MOA of Class III antiarrhythmics?
K+ channel blockers
What is the antiarrhythmic class for beta blockers?
Class II
What is the antiarrhythmic class for K+ channel blockers?
Class III
What is the effect of K+ channel blockers are cardiac depolarization?
K+ channel blockers lengthen the refractory period and prolong the initial action potential. This slows development of a new action potential
This antiarrhythmic is contraindicated in patients post-MI due to risk of arrhythmias. What other ADRs are associated with this drug?
Flecainide - blurred vision, heart failure
This antiarrhythmics have little affect on the SA/AV node and are used to treat life-threatening ventricular arrhythmias.
Lidocaine, mexiletine
What is the antiarrhythmic class for Na+ channel blockers?
Class I
What ADRs are associated with Amiodorane?
Hyper/Hypothyroidism, blue skin, pulmonary fibrosis, corneal deposits
This anti-arrhythmic produces transient asystole.
Adenosine
What ADRs are associated with Class IB antiarrhythmics?
Lidocaine, mexiletine - CNS effects (drowsiness, dizziness, confusion, etc.)
Class IB antiarrhythmics have a low affinity for Na+ channels and are extremely fast acting. What drugs belong to this class?
Lidocaine, mexiletine
What is the primary treatment for acute supraventricular tachycardia?
Adenosine
What is the difference between the absolute and relative refractory periods?
In the absolute refractory period, Na+ channels are inactivated and no amount of stimulus can trigger depolarization.
In the relative refractory period, Na+ channels are in the closed state. They A depolarization may occur with increased stimuli.
What are the Beta1 selective antiarrhythmics?
Metropolol, esmolol
What is the MOA of Class IV antiarrhythmics?
Ca2+ channel blockers
What is the MOA of adeonsine?
Antagonizes the effects of cAMP to reduce Ca+ current in nodal cells
What is the MOA of Class II antiarrhythmics?
Beta blockers
These anti-arrhythmics slow SA/AV nodal conduction and are used to treat supraventricular tachycardia.
Verapamil, diltiazem
This antiarrhythmic is broken down into a potent active metabolite that blocks K+ channels.
Procainamide
What ADRs are associated with quinidine?
Cinchonism (tinnitus, blurred vision, headache), anticholinergic symptoms
Drugs that block these ion channels decrease conduction velocity.
Na+ channel blockes
