Anti-Arrhythmia Drugs

Front 1

Name the Class IA Drugs and Mechanism of Action and the Effect

Back 1

Drugs: Quinidine Procainamide Dysopyramide (QPD)

Remember: "Membrane stabilizers which prolong refractory period"

Mechanism of Action: Sodium Channel Blocker,

Effect: Slows Phase 0 DEPOLARIZATION, MODERATE PHASE 0

Front 2

Name the Class IB Drugs
Name the Mechanims of Action and Effect

Back 2

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

Front 3

Class IC Drugs
Name the mechanism of action
Name the effect
What other Class has a similar mechanism of action?

Back 3

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

Front 4

Name the Class II Drugs and Action (Name the phase involved also)
What two classes of drugs are similar to Class II Drugs?

Back 4

Drugs: Propanolol, Esmolol, Atenolol, and Sotolol (All the olols)

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

Similar Classes: Class IA and Class IC because they both DEPOLARIZE.

Front 5

Name the Class III Drugs and Action (include the phase involved)
What other class of drug is similar in its action?

Back 5

Drugs: Amiodarone, Sotolol, Dofetalide, and Ibutilide
(ASDI)

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)

Front 6

Name the Class IV Drugs and Action

Back 6

Drugs: Verapamil and Dilitiazem

Action: Calcium Channel Blockers --> it shortens action potential
(You should know this by now!)

Front 7

What is Sotolol's Dual Effect?

Back 7

Works as a Beta Adrenergic Blocker and is a Potassium Channel Blocker

Front 8

Quinide

Back 8

Class IA

Front 9

Procainamide

Back 9

Class IA

Front 10

Dysopyramide

Back 10

Class IA

Front 11

Lidocaine

Back 11

Class IB

Front 12

Phenytoin

Back 12

Class IB

Front 13

Mexiletine

Back 13

Class IB

Front 14

Encainide

Back 14

Class IC

Front 15

Flecainide

Back 15

Class IC

Front 16

What is Quinide used for?
What is it mechanism of Action?
What is unique about Quinide

Back 16

1) To treat both atrial and ventricular arrhythmias
2) It INCREASES the refractory period.
3) Its the first anti-arrhythmic used.

Front 17

What is Procainamide's mechanism of action (MOA)?
It's MOA is similar to what other drug?

Back 17

1) It increases the refractory period but has side effects.

2) Similar to Quinidine because it also increases the refractory period.

Front 18

What is Dispyramide used for? How is that different from Quinidine?

What is MOA of Dispyramide?

Back 18

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!)

Front 19

What are some disadvantages of Quinidine?

What are some non-cardiac adverse effects of Quinidine?

Back 19

It has atropine like properties --> promotes xerostomia!

Noncardiac Adverse Effects:
diarrhea, thrombocytopenia, hepatitis, bone marrow suppression, lupus syndrome, cinchonism (headaches, tinnitus), asthma;

Front 20

How is Quinidine related to Hypotension?

Back 20

Because it has mild adrenergic blockade (useful for hypertensive patients)

Front 21

What is Quinidine being replaced by? What class are these drugs in?

Back 21

Amiodarone and Verapamil ( Ca antagonists) -> CLASS IV DRUGS!

Front 22

Describe Cinchonism?

Back 22

ringing of ear, splitting headaches (this is one of the reasons patients are non-compliant with the drug). This is an important side effect.

Front 23

What is Tosades De Pointe? What drug has this adverse effect?

Back 23

Its a type of arrhythmia. Its like splitting of the beat. It has a prolonged QT interval so it has an abnormal EKG.

Front 24

Quinidine has xerostomia as a side effect which would categorize it as what kind of drug?

Back 24

Anti-Muscarinic

Front 25

What is Procainamide used to treat?
What are the potential side effects of this drug?

Back 25

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)

Front 26

What is the advantage of procainamide over quinidine?

Back 26

less atropine like properties

Front 27

What is the most common side effect of Procainamide?

Back 27

Systemic Lupus Erthematosus (SLE) like syndromes

Front 28

What type of side effects does Disopyramide show?

Back 28

Anti-cholinergic side effects

Front 29

What is the advantage of Class IB over Class IA?

What does it mean to say that Class IB drugs are "use-dependent"?

Back 29

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.

Front 30

What type of arrhythmias is Lidocaine useful to treat?

Back 30

digitalis-associated arrhythmias

Front 31

What drug is Mexiletine similar to?
Where is it derived from?

Back 31

1) Similar to Lidocaine in terms of activity.

2) Oral Lidocaine Derivative

Front 32

What kind of drug is Phenytoin also used for (besides anti-arrhtymia)?

Back 32

Its also an anti-convulsant drug.

Front 33

What are the side effects of Class IB drugs?

Back 33

Can aggravate
pre-existing arrhythmias,

Can also cause agitation, drowsiness, slurred-speech, convulsions

Front 34

What are some contra-indications of Class IB drugs?

Back 34

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.

Front 35

What kind of ROUTE should Lidocaine be used?
What kind of emergency treatment is Lidocaine the drug of choice?

Back 35

1) Intravenous

2) Ventricular Arrhythmias

Front 36

What is Tocainide?

Back 36

Its similar to Lidocaine in terms of mechanism of action and adverse action but given ORALLY and thus has a SLOWER ONSET.

Front 37

What is Mexiletine limited by?

Back 37

Pulmonary Toxicity

Front 38

What is the mechanism of action of Flecainide?

Back 38

It works by slowing the conduction in all parts of the heart AND inhibits abnormal automaticity (therefore it can inhibit the ectopic heart beats)

Front 39

What is the mechanism of action of Propafenone? What kind of drugs does it also act like (weakly)?

Back 39

1) It slows conduction
2) It acts weakley as a Beta-Blocker (type 2) and Calcium Channel blocker (type 4).

Front 40

Class of Propafenone

Back 40

Class 1C

Front 41

What are the advantages of Class IC drugs?

Back 41

They work on SLOWER heart beats as opposed to lidocaine which works better on rapid heart beats. They bind TIGHTER also.

Front 42

What are Class IC drugs generally used for?

Back 42

ATRIAL fibrillation and tachycardia w/ abnormal conducting pathways.

Front 43

What are Class IC drugs not recommend for?

Back 43

Post MI

Front 44

Why are Class IC drugs rarely used?

Back 44

Excessive toxicity and there is increased mortality w/ use of the drug.

Front 45

What is Flecainide used for?

Back 45

Prevention of paroxysmal atrial fibrillation (PAF) and paroxysmal supraventricular tachycardia (PSVT) prevention and ventricular arrhythmias.

Front 46

Since Class IC drugs slow Phase 0 depolarization

Back 46

It decreases automaticity (inc threshold) thus increasing the refractory period

Front 47

Why are IC Drugs "Severe Proarrhythmic Drugs"?

Back 47

Because they cause severe worsening of a preexisting arrhythmia or de novo occurrence of life-threatening ventricular tachycardia.

Front 48

What kind of effect does beta adrenergic blockers produce?

Back 48

Inotropic and Chronotropic Effects

Front 49

When are Class II Drugs used?

Back 49

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

Front 50

When are Class II Drugs/Beta Blockers contra indicated?

Back 50

1) Acute Heart Failure
2) Asthma
3) Arrhythmias w/ AV Block

Front 51

What can Propranolol reduce the incidence of?

Back 51

It reduces the incidence of sudden arrhythmatic death after myocardial infarction

Front 52

What is Metoprolol help reduce?
What other kinds of drugs do the same thing?

Back 52

1) reduce the risk of BRONCHOSPASM

2) Other selective B1 adrenergic blockers

Front 53

What does Pidolol do?

Back 53

It has additional partial agonistic activity, it may DECREASE the frequency of cardiac failure.

Front 54

What does Esmolol do? What route of administration does it go through? When is it used?

Back 54

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

Front 55

Is Amiodarone short acting or long acting?

Back 55

IT HAS A LONG DURATION OF ACTION!

Front 56

What class is Amiodarone in? What is it the drug of choice of?

Back 56

1) Class III Drug
2) life-threatening ventricular arrhythmias

Front 57

Can Amiodarone reduce sudden death or prolong survival? Explain.

Back 57

No it cannot but it can improve the quality of life of patients with CHF.

Front 58

How does Amiodarone work? (mechanism of action)

Back 58

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.

Front 59

What is the mechanism of action of Ibutilide? What class is it in?

Back 59

It slows the inward movement of Na+ in addition to delaying K + influx. It is Class 3.

Front 60

What is Sotalol used for? What class is it in?

Back 60

Its in BOTH class II and III! It used to reduce O2 demand and sudden death after MI (similar to Amidarone)

Front 61

What drug is Sotolol similar to? What is its advantage over that drug?

Back 61

Amidarone. Its advantage is that it has the LOWEST INCIDENCE OF SIDE EFFECTS.

Front 62

What is Sotolol's advantage over Type 1 meds?

Back 62

Most effective in preventing mortality due to arrhythmias

Front 63

What are some adverse effects of Class III drugs?

Back 63

May cause arrhythmias, bradycardia, hypotension, congestive heart failure, and cardiac arrest. It also has some extracardiac effects too.

Front 64

What does Ca Channel Blockers do? Name all the functions.

Back 64

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

Front 65

What drugs are in Class IV? Are all Ca channel blockers in Class IV?

Back 65

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

Front 66

What is Diltiazem best useful for?

Back 66

Useful mainly in supraventricular arrhythmias or ventricular arrhythmias caused by coronary spasm

Front 67

What are side effects of Diltiazem?

Back 67

GI disturbances, cardiac toxicity, including heart failure, AV block

Front 68

What does Digoxin do?

Back 68

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

Front 69

What is Digoxin used to treat?

Back 69

- Treatment of atrial fibrillation and flutter
- Diminishes conduction velocity in Purkinje fibers

Front 70

What does Adenosine do?

Back 70

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

Front 71

What does oral erythromycin do?

Back 71

Commonly prescribed drugs increase the AUC of erythromycin by at least 2-fold:
1) Nitroimidazole antifungals
2) Diltiazem, Verapamil.

Front 72

what is the problem of using erythromycin?

Back 72

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.

Front 73

If someone has life threatening arrhythmia like V-fibrillation what would you do?

Back 73

You would adminster Epinephrine or Lidocaine prior to defibrillation

Front 74

What is DC Cardioversion (electroshock) used for?

Back 74

Treatment of choice for unstable, life-threatening cardiac arrhythmias.