Antiarrhythmics

Question 1

Class IA drugs?

Answer 1

Quinidine, disopyramide, procainamide

Question 2

Class IB drugs?

Answer 2

Lidocaine, mexiletine, tocainimide

Question 3

Class IC drugs?

Answer 3

Flecainide, propafenone

Question 4

Class II drugs?

Answer 4

Metoprolol, propranolol, esmolol, atenolol, timolol

Question 5

Class III drugs?

Answer 5

Amiodarone, Ibutilide, Dofetilide, Sotalol (AIDS)

Question 6

Class IV drugs?

Answer 6

Verapamil > diltiazem

Question 7

Which drugs are state dependent (selectively depress tissue that is frequently depolarized such as tachycardia?

Answer 7

Class I drugs

Question 8

What do all class I drugs have in common?

Answer 8

Decrease slope of phase 0, decreasing conduction of AP and thus rate of contraction

Question 9

MOA of class IA?

Answer 9

Increase AP duration, delays phase 3 repolarization (increases ERP and prolonged QTi)

Question 10

MOA of class IB?

Answer 10

Preferentially affects ischemic or depolarized tissue, phase 3 (ERP) is shortened as well as the entire AP

Question 11

MOA of class IC?

Answer 11

NO effect on AP

Question 12

AEs of HA, tinnitus, vertigo and psychosis?

Answer 12

Quinidine - cinchonism

Question 13

Drug induced lupus?

Answer 13

Procainamide

Question 14

Best for post-MI?

Answer 14

Class IB drugs

Question 15

Contraindicated post-MI as it may cause arryhthmias?

Answer 15

Class IC drugs

Question 16

May exacerbate heart failure?

Answer 16

Class IC drugs (watch out in pts with low ejection fraction)

Question 17

MOA of class II drugs?

Answer 17

Decreases SA and AV node activity by decreasing cAMP, decreasing Ca current, decreasing contractility and HR. Suppress abnormal pacemakers by decreasing slope of phase 4. Increases PR interval by affecting AV node particularly.

Question 18

1st line for persistent a-fib in presence of structural heart damage?

Answer 18

B-blockers

Question 19

AEs of B-blockers?

Answer 19

Impotence, exacerbation of asthma, bradycardia, AV block, CHF, sedation/sleep alterations, may mask signs of hypoglycemia

Question 20

Tx for B-blocker OD?

Answer 20

Glucagon

Question 21

MOA of class III drugs?

Answer 21

Block K efflux, increases AP duration and ERP (prolonged QTi)

Question 22

AEs of sotalol?

Answer 22

Torsades, excessive B-block

Question 23

AEs of ibutilide?

Answer 23

Torsades

Question 24

AEs of amiodarone?

Answer 24

Pulmonary fibrosis, hepatotoxicity, thyroid toxicity, corneal deposits, blue/gray skin deposits resulting in photodermatitis, ataxia, CV effects

Question 25

Why can amiodarone block Na, K, and C and have alpha and B-blocking effects?

Answer 25

It alters the lipid membrane

Question 26

MOA of class IV drugs?

Answer 26

Block Ca channels in SA and AV nodes, slowing phase 4 depolarization, decreasing conduction velocity, prolonging PR interval and ERP

Question 27

MOA of adenosine?

Answer 27

Increase K efflux out of SA and AV nodal cells, hyperpolarizing the cell and decreasing HR

Question 28

Use for adenosine?

Answer 28

Dx/abolishing SVTs

Question 29

DOA for adenosine?

Answer 29

VERY short (15 secs)

Question 30

AEs of adenosine?

Answer 30

Flushing, hypotension, chest pain, dyspnea

Question 31

What blocks the effects of adenosine?

Answer 31

Theophylline and caffeine

Question 32

MOA of K?

Answer 32

Increases threshold for cardiac APs, decreasing excitation and thus HR

Question 33

Use for K?

Answer 33

Suppresses ectopic pacemakers, esp those assoc with digoxin toxicity

Question 34

Use for Mg?

Answer 34

Torsades, digoxin toxicity

Question 35

MOA of digoxin?

Answer 35

Inhibits Na/K ATPase, which inhibits the Na/Ca exchanger causing increased contractility; stimulates vagus nerve causing decreased HR

Question 36

Use for digoxin?

Answer 36

CHF, a-fib

Question 37

AEs of digoxin?

Answer 37

N/V/D, blurry yellow vision, ECG changes (increased PRi, decreased QTi, ST-scooping, T-wave inversion), cardiac arrythmias, hyperkalemia

Question 38

What exacerbates digoxin AEs?

Answer 38

1) Hypokalemia 2) Renal failure 3) Quinidine

Question 39

Digoxin toxicity tx?

Answer 39

Tx the hypokalemia, anti-dig Fab, lidocaine, Mg

Question 40

Worst AE of digoxin?

Answer 40

Ventricular tachyarrhythmias