Antiarrhythmics Flashcards Preview

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Flashcards in Antiarrhythmics Deck (48):
1

Name the classes

Class 1 sodium channel blockers, class 2 beta-adrenoreceptor blockers, class 3 potassium channel blockers, class 4 calcium channel blockers

2

Class 1 acts on what phase of AP?

Phase 0

3

Subgroups of class 1 and their effects on AP?

1A prolong AP duration, 1B shorten AP duration, 1C no effect

4

Drugs in class 1A?

Procainamide, disopyramide, quinidine

5

MOA of class 1A drugs?

Use- and state-dependent block of Na current channels, some block potassium current channels, slowed conduction velocity and pacemaker activity, prolonged AP duration and refractory period

6

Treatment for class 1A overdose

Sodium Lactate

7

Class 1B drugs?

Mexiletine, Tocainide, Lidocaine
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1B is Best post MI

8

MOA of Class 1B?

Reduces AP duration, slows recovery of sodium channels from inactivation leading to prolonged ERP, selectively affects ischemic or depolarized Purkinje and ventricular tissue

9

SE of Tocainide

Agranulocytosis

10

Least cardiotoxic among antiarrhytmics

Lidocaine

11

Drugs that can cause agranulocytosis

CCCAPIT -- clozapine, co-tri, colchicine, aminopyrine, phenylbutazone, PTU, indomethacin, Tocainide

12

DOC for ventricular arrhythmias post MI, digoxin-induced arrhythmia

lidocaine

13

Drugs in Class 1C

Propafenone, Encainide, Moricizine
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1C is Contraindicated post MI

14

Used in refractory arrhythmias

Class 1C

15

MOA of Class 1C

Selective use and state-dependent block of Na current, slowed conduction velocity and pacemaker activity

16

Used in WPW

Procainamide and amiodarone

17

MOA of Class 2

Primarily cardiac beta-adrenoceptor blockade and reduction in cAMP

18

Class 2 acts on what phase of AP?

Phase 4

19

Have class 2 and class 3 effects

Sotalol and amiodarone

20

Used in post MI prophylaxis against sudden death

Propranolol

21

Classification system

Singh-Vaughan Williams Classification

22

Beta blocker that lacks local anesthetic effect

Timolol

23

Class 3 acts on what phase of AP?

Phase 3

24

Which antiarrhythmics have the highest risk of causing torsades?

Class 3

25

MOA of class 3?

Blockade of potassium channels responsible for repolarization of AP, increase ERP, and reduce the ability of the heart to respond to rapid tachycardias

26

Drugs in class 3

Amiodarone, Ibutilide, Dofetilide, Sotalol
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27

Most efficacious of all antiarrhythmics?

Amiodarone
Has groups 2 and 4 activities too

28

MOA of class 4

Cause a state and use dependent selective depression of calcium currents, AV conduction velocity is decreased and effective refractory period is increased

29

Amiodarone side effects, toxicity

Pulmonary fibrosis, paresthesias, tremors, thyroid dysfunction, corneal deposits, skin deposits

30

Why are dihydropyridine CCBs not useful as antiarrhythmics ?

They evoke compensatory sympathetic discharge which facilitates arrhythmias rather than terminating them

31

Examples of class 4 drugs

Verapamil, diltiazem

32

DOC for paroxysmal SVT?

Adenosine- miscellaneous antiarrhythmics

33

Miscellaneous antiarrhythmics

Adenosine, potassium ion, magnesium ion

34

Beta blocker that lacks local anesthetic effect

Timolol

35

Class 3 acts on what phase of AP?

Phase 3

36

Which antiarrhythmics have the highest risk of causing torsades?

Class 3

37

MOA of class 3?

Blockade of potassium channels responsible for repolarization of AP, increase ERP, and reduce the ability of the heart to respond to rapid tachycardias

38

Drugs in class 3

Amiodarone, Ibutilide, Dofetilide, Sotalol
AIDS

39

Most efficacious of all antiarrhythmics?

Amiodarone
Has groups 2 and 4 activities too

40

MOA of class 4

Cause a state and use dependent selective depression of calcium currents, AV conduction velocity is decreased and effective refractory period is increased

41

Amiodarone side effects, toxicity

Pulmonary fibrosis, paresthesias, tremors, thyroid dysfunction, corneal deposits, skin deposits

42

Why are dihydropyridine CCBs not useful as antiarrhythmics ?

They evoke compensatory sympathetic discharge which facilitates arrhythmias rather than terminating them

43

Examples of class 4 drugs

Verapamil, diltiazem

44

DOC for paroxysmal SVT?

Adenosine- miscellaneous antiarrhythmics

45

Miscellaneous antiarrhythmics

Adenosine, potassium ion, magnesium ion

46

Increase QRS duration

class 1C

47

Beta blockers with partial agonist activity

Pindolol, acetabulol

48

Prolongs PR interval

Class 2 and class 3