Anti-Arrythmics

Question 1

Class IA - Sodium channel blockers that prolong repolarization

Answer 1

Quinidine, procainamide, disopyramide

Question 2

Class IB - Na blockers the shorten repolarization

Answer 2

lidocaine, tocainide, mexiletine, phenytoin

Question 3

Class IC - Na blockers with little effect on repolarization

Answer 3

felcainide, propafenone, moricizine

Question 4

Class II Beta Blockers

Answer 4

Propranolol, metoprolol, atenolol, esmolol, SOTALOL

Question 5

Class III K+ blockers

Answer 5

Amiodarone, SOTALOL, bretylium, ibutilide, dofetilide

Question 6

Class IV Ca2+ channel blockers

Answer 6

verapamil, diltiazem

Question 7

Class V Antiarrythmics w unknown mech

Answer 7

adenosine, digoxin

Question 8

Class IA indications

Answer 8

ventricular arrhythmias, prevention of paroxysmal recurrent atrial fibrillation, WPW (procainamide)

Question 9

Class IA contraindications

Answer 9

heart block, sinus node disfunction, cariogenic shock, severe uncompensated heart failure, SLE (procainamide)

Question 10

Class IA side effects

Answer 10

arrhythmias (AV block, torsades des pointes), cinchonism , thrombocytopenia, agranulocytosis, hypersensitivity, lupus like syndrome (procainamide), hypotension (dysopyramide)

Question 11

Class IB antiarrhytmics mechanism

Answer 11

block Na+ in refractory state, decrease action potential and increase effective refractory period

Question 12

Class IB indications

Answer 12

trtm/proph of MI(risk of systole), ventricular tachycardia, epilepsy (Phenytoin)

Question 13

Class IB contraindications

Answer 13

sinoatrial disorders, total AV block, epilepsy/convulsions, porphyria

Question 14

Class IB side effects

Answer 14

hypotension, bradycardia, drowsiness, dizziness, convulsions, paresthesia, hep failure(lidocaine), mixeletin and phenytoin also have side effects which I must read.

Question 15

Class IC action

Answer 15

most potent, little effect on repolarization

Question 16

Class IC indications

Answer 16

prevents p. atrial fib, ventricular tachyarrythmia

Question 17

Class IC contraindications

Answer 17

heart failure, history of MI

Question 18

Class IC side effects

Answer 18

anorexia, nausea, vomitting, constipation, dizziness, visual disturbances, arrhythmias

Question 19

Class II (Beta blocker) Indications

Answer 19

decrease MI mortality, prevent recurrence of tachyarrhythmias

Question 20

Potassium Channel blockers (Class III) action

Answer 20

prolong cardiac action pot duration and effective refractory; amiodarone blocks Na and Ca, sotalol is BB with class III act

Question 21

Sotalol pharmacokinetics

Answer 21

rapid and completely abs after oral, 12 hour half life

Question 22

Amiodarone pharmacokinetics

Answer 22

20-100 day half life, slow onset of activity, slow stabilization of blood levels, long CL of drug in toxicity

Question 23

Class III interactions

Answer 23

amiodarone increases level of Digoxin and effects of Warfarin and procainamide

Question 24

Class III indications

Answer 24

Supraventricular arrhythmias, atrial fibrillation and flutter, ventricular tachycardias

Question 25

Class IV mechanism

Answer 25

CA antagonists, shorten phase 2 AP, decrease AP duration; in nodal cells (Ca spikes initial conduction)

Question 26

Class IV indications

Answer 26

prevent recurrence of PStachycardia, reduce ventricular rate in patents with Afib and Aflutter

Question 27

Class IV contraindications

Answer 27

heart block, heart failure, WPW

Question 28

Other (Adenosine)

Answer 28

myocyte hyper polarization and delay conduction; rapid metabolism and half life of 10 seconds, used in supra ventricular arrhythmias and not used in heart block and sick sinus, side effects facial flushing chest pain and dyspnea <30 seconds, IV

Question 29

Mechanism of Action of Anti-arrhythmics

Answer 29

Class IA,IB,IC work in phase O to lower sodium influx into ceLL, Class IV works after phase 2 Ca2+ slow influx, depress phase 4 and prolong phase 1 and 2, Class III prolongs phase 3, increases repolarization and refractoriness, Class II depresses phase 4 with spontaneous depolarization and slow SA node impulses, - adrenergic stimulation of cardiac tissue

Question 30

Class IA mechanism of action

Answer 30

block voltage dependent sodium channels in open/refractory state, slows phase O (increases refractory period), phase 4 (reduce automaticity), prolong action potential duration.

Question 31

Class III mechanism of action

Answer 31

potassium channel blockers that prolong cardiac action potential duration and effective refractory period, amiodarone blocks sodium and potassium channels, sotalol is beta blocker with class III activity.

Question 32

Class III pharmacokinetics

Answer 32

sotalol (rapid and completely absorbed orally, 12 hour half life) amiodarone (half life 20-100 days, slow onset of activity, slow stabilization of blood levels and long CL of drug if toxicity occurs)

Question 33

Class III contraindications

Answer 33

pheochromocytoma (Bretylium), AV block, sinus bradycardia/thyroid dysfunction (amiodarone), contraindications of Beta blockers

Question 34

Class III Adverse effects

Answer 34

arrhythmias, hypotension/nausea (Bretylium), thyroid dysfunction (amiodarone), reduced ventricular function (sotalol)

Question 35

Class III administration

Answer 35

Bretylium administered IV while Amiodarone and Sotalol are IV/oral