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74 Cards in this Set

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  • Back
Name the Class IA Drugs and Mechanism of Action and the Effect
Drugs: Quinidine Procainamide Dysopyramide (QPD)

Remember: "Membrane stabilizers which prolong refractory period"

Mechanism of Action: Sodium Channel Blocker,

Name the Class IB Drugs
Name the Mechanims of Action and Effect
Drug: Lidocaine Phenytoin Mexiletine (LPM)

Remember: Membrane stabilizers which "reduce" refractory period

Action: Sodium Channel Blocker

Effect: No change in phase 0, Shortens Phase 3 Repolarization
Class IC Drugs
Name the mechanism of action
Name the effect
What other Class has a similar mechanism of action?
Drug: Flecainide, and Encainide (EF)

Remember: "Membrane stabilizers which slow depolarization”

Action: Sodium Channel Blocker,

Effect: Marked Phase 0, Slows Phase 0 Depolarization.

Similar Class: Class IA
Name the Class II Drugs and Action (Name the phase involved also)
What two classes of drugs are similar to Class II Drugs?
Drugs: Propanolol, Esmolol, Atenolol, and Sotolol (All the olols)

Action: Beta-Adrenergic Blockers --> Suppresses Phase 4

Similar Classes: Class IA and Class IC because they both DEPOLARIZE.
Name the Class III Drugs and Action (include the phase involved)
What other class of drug is similar in its action?
Drugs: Amiodarone, Sotolol, Dofetalide, and Ibutilide

Action: Potassium Channel Blocker, it prolongs Phase 3 repolarization refractory and AP

Similar Drugs: Class IB BECAUSE ITS INVOLVED IN REPOLARIZATION ALSO! (except its a sodium channel blocker)
Name the Class IV Drugs and Action
Drugs: Verapamil and Dilitiazem

Action: Calcium Channel Blockers --> it shortens action potential
(You should know this by now!)
What is Sotolol's Dual Effect?
Works as a Beta Adrenergic Blocker and is a Potassium Channel Blocker
Class IA
Class IA
Class IA
Class IB
Class IB
Class IB
Class IC
Class IC
What is Quinide used for?
What is it mechanism of Action?
What is unique about Quinide
1) To treat both atrial and ventricular arrhythmias
2) It INCREASES the refractory period.
3) Its the first anti-arrhythmic used.
What is Procainamide's mechanism of action (MOA)?
It's MOA is similar to what other drug?
1) It increases the refractory period but has side effects.

2) Similar to Quinidine because it also increases the refractory period.
What is Dispyramide used for? How is that different from Quinidine?

What is MOA of Dispyramide?
1) Used to treat ONLY VENTRICULAR ARRTHYMIAS whereas quinidine is used to treat BOTH atrial and ventricular arrhythmias.

2) The MOA is by EXTENDED duration of action (not increasing refractory period!)
What are some disadvantages of Quinidine?

What are some non-cardiac adverse effects of Quinidine?
It has atropine like properties --> promotes xerostomia!

Noncardiac Adverse Effects:
diarrhea, thrombocytopenia, hepatitis, bone marrow suppression, lupus syndrome, cinchonism (headaches, tinnitus), asthma;
How is Quinidine related to Hypotension?
Because it has mild adrenergic blockade (useful for hypertensive patients)
What is Quinidine being replaced by? What class are these drugs in?
Amiodarone and Verapamil ( Ca antagonists) -> CLASS IV DRUGS!
Describe Cinchonism?
ringing of ear, splitting headaches (this is one of the reasons patients are non-compliant with the drug). This is an important side effect.
What is Tosades De Pointe? What drug has this adverse effect?
Its a type of arrhythmia. Its like splitting of the beat. It has a prolonged QT interval so it has an abnormal EKG.
Quinidine has xerostomia as a side effect which would categorize it as what kind of drug?
What is Procainamide used to treat?
What are the potential side effects of this drug?
1) acute treatment of supraventricular and ventricular arrhythmias

2) Hypotension, reduced cardiac output, Proarrhythmia (generation of a new arrhythmia) eg. Torsades de Points (QT interval), Dizziness, confusion, insomnia, seizure (high dose), Gastrointestinal effects (common), Lupus-like syndrome (esp. procainamide)
What is the advantage of procainamide over quinidine?
less atropine like properties
What is the most common side effect of Procainamide?
Systemic Lupus Erthematosus (SLE) like syndromes
What type of side effects does Disopyramide show?
Anti-cholinergic side effects
What is the advantage of Class IB over Class IA?

What does it mean to say that Class IB drugs are "use-dependent"?
1) They are less proarrythmogenic than Class 1A drugs

2) Use-dependence: The blocking action of the drug is more potent
when ion channels are open ie. when more APs are firing.
What type of arrhythmias is Lidocaine useful to treat?
digitalis-associated arrhythmias
What drug is Mexiletine similar to?
Where is it derived from?
1) Similar to Lidocaine in terms of activity.

2) Oral Lidocaine Derivative
What kind of drug is Phenytoin also used for (besides anti-arrhtymia)?
Its also an anti-convulsant drug.
What are the side effects of Class IB drugs?
Can aggravate
pre-existing arrhythmias,

Can also cause agitation, drowsiness, slurred-speech, convulsions
What are some contra-indications of Class IB drugs?
1) Hypersensitivity to local anesthetics of amide type.

2) History of grand mal seizures with previous lidocaine use

3) Greater than 70 years of age.
What kind of ROUTE should Lidocaine be used?
What kind of emergency treatment is Lidocaine the drug of choice?
1) Intravenous

2) Ventricular Arrhythmias
What is Tocainide?
Its similar to Lidocaine in terms of mechanism of action and adverse action but given ORALLY and thus has a SLOWER ONSET.
What is Mexiletine limited by?
Pulmonary Toxicity
What is the mechanism of action of Flecainide?
It works by slowing the conduction in all parts of the heart AND inhibits abnormal automaticity (therefore it can inhibit the ectopic heart beats)
What is the mechanism of action of Propafenone? What kind of drugs does it also act like (weakly)?
1) It slows conduction
2) It acts weakley as a Beta-Blocker (type 2) and Calcium Channel blocker (type 4).
Class of Propafenone
Class 1C
What are the advantages of Class IC drugs?
They work on SLOWER heart beats as opposed to lidocaine which works better on rapid heart beats. They bind TIGHTER also.
What are Class IC drugs generally used for?
ATRIAL fibrillation and tachycardia w/ abnormal conducting pathways.
What are Class IC drugs not recommend for?
Post MI
Why are Class IC drugs rarely used?
Excessive toxicity and there is increased mortality w/ use of the drug.
What is Flecainide used for?
Prevention of paroxysmal atrial fibrillation (PAF) and paroxysmal supraventricular tachycardia (PSVT) prevention and ventricular arrhythmias.
Since Class IC drugs slow Phase 0 depolarization
It decreases automaticity (inc threshold) thus increasing the refractory period
Why are IC Drugs "Severe Proarrhythmic Drugs"?
Because they cause severe worsening of a preexisting arrhythmia or de novo occurrence of life-threatening ventricular tachycardia.
What kind of effect does beta adrenergic blockers produce?
Inotropic and Chronotropic Effects
When are Class II Drugs used?
1) They are used in treatment of increased sympathetic activity-induced arrhythmias such as stress- and exercise-induced arrhythmias

2) Treatment of atrial flutter and fibrillation

3) AV nodal tachycardia
When are Class II Drugs/Beta Blockers contra indicated?
1) Acute Heart Failure
2) Asthma
3) Arrhythmias w/ AV Block
What can Propranolol reduce the incidence of?
It reduces the incidence of sudden arrhythmatic death after myocardial infarction
What is Metoprolol help reduce?
What other kinds of drugs do the same thing?
1) reduce the risk of BRONCHOSPASM

2) Other selective B1 adrenergic blockers
What does Pidolol do?
It has additional partial agonistic activity, it may DECREASE the frequency of cardiac failure.
What does Esmolol do? What route of administration does it go through? When is it used?
Esmolol is a very short-acting β1-adrenergic blocker that is used in the by intravenous route in acute arrhythmias occurring during surgery or emergencies
Is Amiodarone short acting or long acting?
What class is Amiodarone in? What is it the drug of choice of?
1) Class III Drug
2) life-threatening ventricular arrhythmias
Can Amiodarone reduce sudden death or prolong survival? Explain.
No it cannot but it can improve the quality of life of patients with CHF.
How does Amiodarone work? (mechanism of action)
prolongs action potential by IT delays K+ efflux but it also has many other effects characteristic of other classes thus having lots of side effects.
What is the mechanism of action of Ibutilide? What class is it in?
It slows the inward movement of Na+ in addition to delaying K + influx. It is Class 3.
What is Sotalol used for? What class is it in?
Its in BOTH class II and III! It used to reduce O2 demand and sudden death after MI (similar to Amidarone)
What drug is Sotolol similar to? What is its advantage over that drug?
Amidarone. Its advantage is that it has the LOWEST INCIDENCE OF SIDE EFFECTS.
What is Sotolol's advantage over Type 1 meds?
Most effective in preventing mortality due to arrhythmias
What are some adverse effects of Class III drugs?
May cause arrhythmias, bradycardia, hypotension, congestive heart failure, and cardiac arrest. It also has some extracardiac effects too.
What does Ca Channel Blockers do? Name all the functions.
They slow rate of AV-conduction in patients with atrial fibrillation, Decreases SA and Purkinje fiber automaticity, slows conduction through and increases refractory period of AV node, negative inotropy
What drugs are in Class IV? Are all Ca channel blockers in Class IV?
Includes Verapamil and diltiazem, but not nifedipine (or the other dihydropyridine Ca2+ antagonists), are representative of this class being more effective on the heart than blood vessels
What is Diltiazem best useful for?
Useful mainly in supraventricular arrhythmias or ventricular arrhythmias caused by coronary spasm
What are side effects of Diltiazem?
GI disturbances, cardiac toxicity, including heart failure, AV block
What does Digoxin do?
Inhibitor of Na-K-ATPase pump that has positive ionotropic effects on myocardium. 
      It Increases phase 4 depolarization rate (increased automaticity) and decreased AV conduction rate
What is Digoxin used to treat?
- Treatment of atrial fibrillation and flutter
- Diminishes conduction velocity in Purkinje fibers
What does Adenosine do?
Naturally occurring nucleoside that activates K+ channels (similar to acetylcholine) in SA and AV nodes.
- Decreases conduction velocity
- Prolongs refractory period
- Decreases automaticity in A-V node

***Rarely used since high doses are needed, short effective t1/2
What does oral erythromycin do?
Commonly prescribed drugs increase the AUC of erythromycin by at least 2-fold:
1) Nitroimidazole antifungals
2) Diltiazem, Verapamil.
what is the problem of using erythromycin?
There is a risk of sudden death from cardiac causes. The incidence ratio of sudden cardiac death was 5.35 (1.72-16.64, 95% CI) in patients using erythromycin and a CYP3A inhibitor.
If someone has life threatening arrhythmia like V-fibrillation what would you do?
You would adminster Epinephrine or Lidocaine prior to defibrillation
What is DC Cardioversion (electroshock) used for?
Treatment of choice for unstable, life-threatening cardiac arrhythmias.