Drugs For Cardiac Arrhythmias (Konorev) Flashcards
What are the 1B Na channel blocking drugs?
Lidocaine
Mexiletine
Which cell types have a fast AP?
Ventricular contractile cardiomyocytes
Atrial cardiomyocytes
Purkinje fibers
Which cell types have a slow (pacemaker) AP?
SA node cells
AV node cells
What are the 1C Na channel blocking drugs?
Flecainide
Propafenone
What are the class 2 antiarrhythmic drugs?
Beta blockers
Esmolol and propanolol
What are class 3 antiarrhythmic drugs?
K channel blocking drugs Amiodarone Dronedarone Sorta lol Dofetilide Ibutilide
What are class 4 antiarrhythmic drugs?
Cardioactive Ca channel blockers
Verapamil and Diltiazem
Class 1A drugs preferentially bind to __ channels
Open (activated) Na
Class 1A drugs have what effects on the following:
- K channels: ___
- AP duration: ___
- QRS and QT intervals: ___
Block
Prolong
Prolong
This 1a drug is used to tx sustained V tach, directly depresses the activities of SA and AV nodes, and possesses antimuscarinic activity
Procainamide
What are adverse effects of Procainamide?
Cardiac –> QT prolongation, induce Torsade de pointes and syncope
Extracardiac –> lupus syndrome, nausea, diarrhea, and agranulocytosis
This 1a drug is a natural alkaloid from Cinchona bark that is used occasionally for restoring rhythm in A flutter/fib pts with normal (but arrhythmic) hearts
Quinidine
What are adverse effects of quinidine?
Cardiac –> QT prolongation, induce Torsades
Extracardiac –> GI side effects, headache, dizziness, tinnitus, thrombocytopenia, hepatitis, fever
This 1a drug is used for tx of recurrent V Tac
Disopyramide
What are adverse effects of Disopyramide?
Cardiac –> QT prolongation, induce torsades, negative inotropic effect
Extracardiac –> atropine-like symptoms
Class 1B drugs bind to ___ channels
Inactivated Na , preferentially bind to depolarized cells
This 1B drug blocks inactivated Na channels-selectively blocks conduction in depolarized tissue, making damaged tissue completely “electrically silent”. It is used in mono- and polymorphic V Tac
Lidocaine: extensive 1st pass metabolism and only by IV route
This is the least toxic of all Class I drugs
__ is an orally active 1B drug used for ventricular arrhythmias, to relieve chronic pain (esp pain d/t diabetic neuropathy and nerve injury)
Mexiletine
Adverse effects: tremor, blurred vision, nausea, lethargy
Class 1C drugs block Na channels to slow impulse conduction and preferentially bind to __ Na channels
Open (activated)
They also block certain K channels
What do 1C drugs do to the QRS complex?
Prolong QRS
This 1C drug blocks Na and K channels and has no antimuscarinic effects. It is used to tx pts with normal hearts, supraventricular arrhythmias including AF, paroxysmal SVT (AVNRT, AVRT).
Flecainide
This 1C drug possesses weak B-blocking activity and used to prevent paroxysmal AF and SVT in pts without structural disease and also used in sustained ventricular arrhythmias
Propafenone
What are some adverse effects of Propafenone and what should you no combine with?
Exacerbates ventricular arrhythmias
Metallic taste
Constipation
Do NOT combine with CYP2D6 and CYP3A4 inhibitors as risk of proarrhythmia may be increased
What effects do class 2 drugs have on the following:
- SA node: ___
- AV node: ___
- Ventricular myocardium: ___
SA node: decrease HR (Increase RR interval)
AV node: decrease AV conductance (Increase PR interval)
Ventricular myocardium: decrease Ca overload, prevent delayed after-depolarizations
What are clinical indications for Propanolol (class 2)?
Arrhythmias associated with stress
Re-entrant arrhythmias that involve the AV node
A fib and flutter
Arrhythmias associated with MI
This class 2 drug is a selective B1 blocker with a short half life (10 min) on continuous IV fusion
Esmolol
What effects do Class 3 drugs have on the following:
- AP: ___
- QT interval: ___
- Refractory period:___
Prolong AP duration
Prolong QT interval
Prolong refractory period
This class 3 drug blocks K and inactivated Na channels, prolongs QT interval and APD uniformly over wide range of HR’s. It possesses adrenolytic activity, has Ca channel blocking activities, cuases bradycardia and slows AV conduction. It can also cause peripheral vasodilation and is used to Tx ventricular arrhythmias
Amiodarone
Amiodarone is metabolized by ___
CYP3A4
1/2 life affected by drugs that inhibit CYP3A4 (Cimetidine) or induce it (Rifampin)
What are some adverse effects of Amiodarone?
Cardiac –> AV block and bradycardia
Extracardiac –> fatal pulm fibrosis, hepatitis, photodermatitis, depositis of drug in cornea and other eye tissues, blocks peripheral conversion of thyroxine to triiodothyronine
This class 3 drug blocks multiple K channels, blocks Na current, blocks L-type Ca current, and has stronger antiadrenergic effects than Amiodarone
Dronedarone
What is the Black box warning for Dronedarone?
Increases risk of mortality in pts with decompensated HF (Class IV) and in pts with a recent decompensation of HF requiring hospitalization
This drug is a class 2 (non-selective B blocker) and class 3 agent (prolongs APD). It is used to tx life-threatening ventricular arrhythmias and maintenance of sinus rhyth in pts with A fib.
Sorta lol
What are adverse effects of Sotalol?
Depress cardiac function
Provoke Torsades
This class 3 drug specifically blocks rapid component of delayed rectifier K current. It has a very narrow therapeutic window and used to convert AF to the sinus rhythm and maintain sinus rhythm after cardioversion.
Dofetilide
What are adverse effects of Dofetilide?
QT prolongation and increased risk of ventricular arrhythmias
What effects do Class 4 drugs have on the following:
- Slope of phase 0 depolarization: ___
- SA node depolarization: ___
- AV node conduction time: ___
- AP duration and refractory period in AV node: __
Decrease slope of phase 0 depolarization
Slow SA node depol., causing bradycardia
Prolong AV node conduction time
Prolong AP duration and refractory period in AV node
What are clinical uses of Diltiazem?
Prevention of paroxysmal SVT
Rate control in A fib and A flutter
What are adverse effects of class 4 drugs?
Cardiac –> negative inotropy, AV block, SA node arrest, bradyarrhythmias, hypotension
Extracardiac–> constipation (Verapamil)
This drug activates K current and inhibits Ca funny currents, causing marked hyperpolarization and suppression of APs in pacemaker cells. It inhibits AV conduction and increases nodal refractory period. It is used clinically to convert sinus rhythm in paroxysmal SVT
Adenosine
What are adverse effects of adenosine?
SOB Bronchoconstriction Chest burning AV block Hypotension
Which antiarrhythmic drug classes can cause long QT syndrome and torsade de pointes arrhythmias?
Class 1a and 3
What are the 1A Na channel blocking drugs?
Quinidine
Procainamide
Disopyramide
