Antiarrhythmic Drugs

Front 1

possible mechanisms fo arrhythmia?

Back 1

abnormal impulse generation
altered impulse conduction (re-entry)

Front 2

types of abnormal impulse generation?

Back 2

increased automaticity
afterdepolarizations

Front 3

early afterdepolarization?

Back 3

arises from plateau prior to full repolarization;
exacerbated at slow rates;
long QT-related arrhythmias such as torsades de pointes

Front 4

delayed afterdepolarization?

Back 4

arises from resting potential;
thought to be related to Ca in cell;
exacerbated by rapid rates;
some digitalis-induced arrhythmias

Front 5

general properties of antiarrhythmic drugs?

Back 5

may increase refractory period or slow conduction;
low therapeutic index (sometimes serious adverse effects even at therapeutic ranges);
proarrhythmic effects (worsen current or induce new arrhythmias)

Front 6

class I drugs?

Back 6

quinidine
procainamide
disopyramide
lidocaine
mexiletine
propafenone
flecainide

Front 7

class II drugs?

Back 7

β blockers

Front 8

class III drugs?

Back 8

bretylium
sotalol
amiodarone
ibutilide
dofetilide

Front 9

class IV drugs?

Back 9

verapamil
diltiazem

Front 10

misc antiarrhythmic drug?

Back 10

adenosine

Front 11

examples of use of quinidine?

Back 11

atrial fibrillation and flutter
serious ventricular arrhythmias

Front 12

electrophysiologic actions of quinidine?

Back 12

blocks Na and K channels
alpha blockade
antivagal effects

Front 13

effect of blocking Na channels?

Back 13

decrease conduction velocity

Front 14

effect of blocking K channels?

Back 14

increase action potential duration (ERF);
associated with increased QT interval;
can be associated with torsades de pointes and early afterdepolarization

Front 15

antivagal effect of quinidine?

Back 15

may cause paradoxical increase in ventricular rate in patients with atrial flutter as AV node is more likely to transmit more impulses to ventricles

Front 16

quinidine pharmacokinetics?

Back 16

well absorbed
hepatic metabolism
20% excreted unchanged in urine

Front 17

adverse effects of quinidine?

Back 17

cardiac (high risk of arrhythmias)
GI (diarrhea)
cinchonism (headache, tinnitus)
hypersensitivity (thrombocytopenia, hepatotoxicity)

Front 18

thrombocytopenia as adverse effect?

Back 18

quinidine

Front 19

quinidine + digoxin interaction?

Back 19

increased plasma digoxin level

Front 20

quinidine + phenytoin or phenobarbital interaction?

Back 20

decreased quinidine level

Front 21

quinidine + CYP2D6 interaction?

Back 21

quinidine can inhibit CYP2D6

Front 22

which P450 can quinidine inhibit?

Back 22

CYP2D6

Front 23

example of use of procainamide?

Back 23

serious ventricular arrhythmias

Front 24

procainamide metabolism and consequence?

Back 24

acetylation;
NAPA is active metabolite;
greater incidence of drug induced lupus and (+)ANA with slow acetylators

Front 25

procainamide metabolite and its effect?

Back 25

N-acetylprocainamide (NAPA): increases AP duration, need to monitor both

Front 26

electrophysiologic actions of procainamide?

Back 26

Na and K channel blocker

Front 27

adverse effects of procainamide?

Back 27

cardiac
hypotension
nausea
drug induced lupus
agranulocytosis

Front 28

agranulocytosis?

Back 28

procainamide

Front 29

example of use of disopyramide?

Back 29

serious ventricular arrhythmias

Front 30

disopyramide actions?

Back 30

block Na and K channels
anticholinergic
negative inotropic effect

Front 31

disopyramide adverse effects?

Back 31

cardiovascular
anticholinergic

Front 32

lidocaine example of use?

Back 32

acute treatment of ventricular arrhythmias

Front 33

lidocaine electrophysiologic action?

Back 33

decreased conduction in depolarized cells (eg ischemia);
block Na channels

Front 34

lidocaine administration?

Back 34

IV due to extensive first pass metabolism when give po;
clearance decreased by liver disease, heart failure, propranolol (due to decreased liver blood flow)

Front 35

lidocaine adverse effects?

Back 35

neurologic: tremor, altered consciousness, seizures;
least cardiotoxic Na channel blocker

Front 36

one of the least cardiotoxic of the currently used sodium channel blockers?

Back 36

lidocaine

Front 37

mexiletine?

Back 37

oral lidocaine-like drug
block Na channels

Front 38

examples of use of mexiletine?

Back 38

serious ventricular arrhythmias
orally effective lidocaine analog

Front 39

flecainide examples of use?

Back 39

maintenance of sinus rhythm in certain supraventricular arrhythmias in patients without structural heart disease

Front 40

flecainide electrophysiologic effects?

Back 40

blocks Na and K channels although does not prolong the AP;
decreased contractility

Front 41

adverse effects of flecainide?

Back 41

blurred vision
can worsen heart failure
cause or exacerbate potentially fatal arrhythmias
can also cause heart block

Front 42

Cardiac Arrhythmia Suppression Trial?

Back 42

showed increased mortality in post-MI patients with premature ventricular contractions treated with flecainide

Front 43

propafenone use?

Back 43

supraventricular arrhythmias

Front 44

propafenone effects?

Back 44

blocks Na channels
β blocking activity

Front 45

propranolol example of use?

Back 45

atrial fibrillation

Front 46

electrophysiologic effects of propranolol?

Back 46

β blockade
membrane stabilizing action

Front 47

amiodarone uses?

Back 47

serious ventricular arrhythmias
also effective in certain supraventricular arrhythmias

Front 48

electrophysiologic effects of amiodarone?

Back 48

blocks K, Na, Ca channels
antiadrenergic
anticholinergic

Front 49

amiodarone effect?

Back 49

increase AP duration
vasodilation

Front 50

amiodarone pharmacokinetics?

Back 50

long terminal half-life (weeks)

Front 51

amiodarone adverse effects?

Back 51

decreased heart rate
pulmonary fibrosis
thyroid dysfunction
corneal microdeposits
photosensitivity, blue-gray discoloration
hepatotoxicity
neuro
can worsen arrhythmias
inhibits p450
hypotension

Front 52

pulmonary fibrosis?

Back 52

amiodarone

Front 53

corneal microdeposits in virtually all?

Back 53

amiodarone

Front 54

photosensitivity and blue-gray discoloration?

Back 54

amiodarone

Front 55

torsades de pointes relatively uncommon despite QT prolongation?

Back 55

amiodarone

Front 56

drug interactions with amiodarone?

Back 56

decreases elimination of several drugs (warfarin, digoxin)

Front 57

amiodarone structure?

Back 57

contain two iodine that are thought to cause thyroid dysfunction

Front 58

dronedarone example of use?

Back 58

atrial fibrillation or atrial flutter in certain patients

Front 59

adverse effects of dronedarone?

Back 59

diarrhea, n/v
QT prolongation
fetal harm possible
drug interactions

Front 60

contraindications for dronedarone?

Back 60

NYHA class IV HF or NYHA class II-III HF with recent decompensation requiring hospitalization or referral to a specialized heart failure clinic;
pregnancy

Front 61

sotalol examples of use?

Back 61

serious ventricular arrhythmias
maintenance of sinus rhythm in patients with symptomatic AFIB/AFL who are currently in sinus rhythm

Front 62

electrophysiologic effects of sotalol?

Back 62

increased AP duration
increase QT interval
decreased conduction velocity in AV node
decreased refractoriness of AV node

Front 63

sotalol action?

Back 63

block K channel
β blocker
racemic mixture

Front 64

adverse effects of sotalol?

Back 64

adverse effects of β blockade
torsades de pointes (proarrhythmic)

Front 65

dofetilide examples of use?

Back 65

maintenance of normal sinus rhythm in patients with atrial fibrillation;
conversion of atrial fibrillation

Front 66

electrophysiologic effects of dofetilide?

Back 66

increases AP duration
block K rectifying channel
increased QT interval

Front 67

excretion of dofetilide?

Back 67

secreted by organic cation system

Front 68

dofetilide administration?

Back 68

oral

Front 69

adverse effects of dofetilide?

Back 69

torsades de pointes
necessary education program for hospitals and prescribers
drug interactions

Front 70

ibutilide example of use?

Back 70

rapid conversion of atrial fibrillation or atrial flutter of recent onset to sinus rhythm

Front 71

ibutilide electrophysiologic effects?

Back 71

increase AP duration
block rectifying K channel
increase inward Na current
increase QT interval

Front 72

ibutilide pharmacokinetics?

Back 72

IV
hepatic metabolism

Front 73

ibutilide adverse effects?

Back 73

torsades de pointes
education program for patients

Front 74

verapamil examples of use?

Back 74

certain supraventricular arrhythmias

Front 75

verapamil actions?

Back 75

blocks activated and inactivated Ca channels;
decreases conduction velocity and increases ERP of AV node;
vasodilation;
decreased myocardial contractility

Front 76

verapamil adverse effects?

Back 76

hypotension
depressed contractility
heart block
etc

Front 77

diltiazem examples of use?

Back 77

certain supraventricular arrhythmias

Front 78

adenosine examples of use?

Back 78

conversion of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm

Front 79

adenosine action?

Back 79

acts on adenosine receptors
slow AV conduction
increased RP in AV node

Front 80

adenosine pharmacokinetics?

Back 80

given by rapid IV administration
half life <10 sec

Front 81

adenosine adverse effects?

Back 81

typically transient (short t1/2)
flushing
headache
hypotension
arrhythmias
heart block
asystole
dyspnea, chest discomfort
drug interactions

Front 82

asystole?

Back 82

adenosine

Front 83

methylxanthine + adenosine interaction?

Back 83

inhibit adenosine receptors to reduce drug effect (caffeine)

Front 84

dipyridamole + adenosine interaction?

Back 84

adenosine uptake inhibitor to increase effect