Pharmacology: Antiarrhythmic Drugs

Front 1

what should be administered in addition with propranolol, amiodarone, or dofetilide when treating atrial fibrillation?

Back 1

anticoagulant to reduce the risk of a stroke.

Front 2

what is the general action of Class 1 antiarrhythmics?

Back 2

blocking voltage-sensitive sodium channels via the same mechanism as local anesthetics

Front 3

what phase of cardiac muscle depolarization do class 1 drugs generally act on and why?

Back 3

phase 0 because they have a high affinity for active rather then resting channels (Na channels) mainly during tachycardia

Front 4

what is the reasoning for the sub-divisions of class 1 drugs?

Back 4

the duration effect on the action potential (how fast or slow the action potential is altered)

Front 5

what is the effect of class 1a drugs? what speed class are they considered

Back 5

they slow the rate of action potential and increase the ventricular eddective refractory period (intermediate class)

Front 6

what effect do class 1b drugs have on the action potential?

Back 6

they decrease the duration of the action potential by shortening repolatization

Front 7

whats the action of class 1c drugs?

Back 7

they cause conduction slowing with little effect of the duration of the action potential or refractory period.

Front 8

what class of drug is quinidine?

Back 8

class 1a

Front 9

what is the moa of quinidine?

Back 9

it binds to open and inactivated Na channels preventing Na influx...also mildly decreases the slope of phase 4 repolarization

Front 10

what is the clinical use for quinidine?

Back 10

to inhibit tachycardias orginiating in the atrium sinuses and ventricals...atrial flutter fib

Front 11

how is quinidine administered, metabolised, and excreted?

Back 11

orally, CYP450, kidney

Front 12

what is a potential adverse effect of quinidine or any anti-arrhythmic?

Back 12

exacerbation of the arrythmia or asystole

Front 13

what are adverse effects of quinidine?

Back 13

nausea vomiting diarrhea

CINCHONISM (blurred vision, tinnitus, adrenergic blocking

Front 14

what are the actions of procainamide? hint what class are they?

Back 14

they are a class 1a and they block the open inactive Na channels which prolong phase 0

Front 15

what are they serious adverse effects of procainamide?

Back 15

reversible lupus erythematosus like syndrome
CNS effect (depression, hallucinations, psychosis)

toxic levels can also cause asystole or ventricular arrhythmias

Front 16

what class is disopyramide and what effect does it have?

Back 16

it produces a greater negative inotropic effect then quinidine or procainamide..also causes peripheral vasoconstriction

Front 17

what are the adverse effects of disopyramide?

Back 17

anticholinergic activity such as dry mouth urinary retention, blurred vision, constipation

Front 18

what class of drug is lidocaine and the MOA?

Back 18

Class 1b

IT SHORTENS PHASE 3 and decreases the duration of the action potential..
they bind and release from Na channels rapidly...usful when the cardiac cell is depolarized or firing rapidly

Front 19

what is the drug of choice for treating emergency cardiac arrhythmias

Back 19

lidocaine

Front 20

what is the therapeutc use for lidocaine?

Back 20

ventricular arrhythmias

Front 21

what is the adverse effects of lidocaine?

Back 21

cardiac arryhmias

CNS disturbances such as drowninessm slurred speach, parasthesia, convulsions

Front 22

what class is mexiletine and tocainide? and what are their actions similar to?

Back 22

class 1b and have similar actions to lidocaine

Front 23

what is mexiletine used for?

Back 23

chronic treatment of ventricular arrhythmias from previous MI

Front 24

what is the toxictiy for tocainide?

Back 24

pulmonary toxicity leading to pulmonary fibrosis

Front 25

what is the action of the class 1c drugs? what are they used for

Back 25

they slowly dissociate from resting sodium channels...used for refractory ventricular arrhythmias

Front 26

what is the class and action of flecainide?

Back 26

class 1c and action is the suppress the phase 0 upstroke of myocardial and purkinje fibers.

Front 27

what are the toxic effect of flecainide?

Back 27

dizziness, blurred vision, headache, and nausea

Front 28

what class of drug is propafenone?

Back 28

class 1c

Front 29

what kinda of antiarrhythmics are class 2 drugs? and what is the actions?

Back 29

beta-adrenergics antagonist...they diminish phase 4 thus depressing automaticity

Front 30

what is the threapeutic use for Beta blockers?

Back 30

tachyarrythmias caused by sympathetic activity

Front 31

that are three drugs in the class 2's?

Back 31

propanolol, esmolol, metoprolol

Front 32

what is the short acting class 2 drug?

Back 32

esmolol

Front 33

which class 2 reduces the risk of bronchospasm?

Back 33

metoprolol

Front 34

what is the action of class 3 drugs?

Back 34

block K channels and diminish the efflux of K

Front 35

along with effects from class 1 2 3 4 actions, what is the dominate effect of amiodarone?

Back 35

prolongation of the action potential duration and the refractory period, thus slowing AP down.

Front 36

what is the therapeutic use for amiodarone?

Back 36

severe refractory supraventricular and ventricular tachyarrhythmias

Front 37

what are toxic effects of amiodarone?

Back 37

interstitial pulmonary fibrosis, ataxia, HYPER OR HYPOTHYROIDISM, liver tox, blue skin discoloration