Antiarrhythmics Flashcards

1
Q

Name the classes

A

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

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2
Q

Class 1 acts on what phase of AP?

A

Phase 0

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3
Q

Subgroups of class 1 and their effects on AP?

A

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

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4
Q

Drugs in class 1A?

A

Procainamide, disopyramide, quinidine

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5
Q

MOA of class 1A drugs?

A

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

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6
Q

Treatment for class 1A overdose

A

Sodium Lactate

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7
Q

Class 1B drugs?

A

Mexiletine, Tocainide, Lidocaine
I Buy Mexican Tacos from Lily
1B is Best post MI

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8
Q

MOA of Class 1B?

A

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

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9
Q

SE of Tocainide

A

Agranulocytosis

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10
Q

Least cardiotoxic among antiarrhytmics

A

Lidocaine

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11
Q

Drugs that can cause agranulocytosis

A

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

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12
Q

DOC for ventricular arrhythmias post MI, digoxin-induced arrhythmia

A

lidocaine

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13
Q

Drugs in Class 1C

A

Propafenone, Encainide, Moricizine
Chicken and Pagkain ni Enrico
1C is Contraindicated post MI

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14
Q

Used in refractory arrhythmias

A

Class 1C

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15
Q

MOA of Class 1C

A

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

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16
Q

Used in WPW

A

Procainamide and amiodarone

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17
Q

MOA of Class 2

A

Primarily cardiac beta-adrenoceptor blockade and reduction in cAMP

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18
Q

Class 2 acts on what phase of AP?

A

Phase 4

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19
Q

Have class 2 and class 3 effects

A

Sotalol and amiodarone

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20
Q

Used in post MI prophylaxis against sudden death

A

Propranolol

21
Q

Classification system

A

Singh-Vaughan Williams Classification

22
Q

Beta blocker that lacks local anesthetic effect

A

Timolol

23
Q

Class 3 acts on what phase of AP?

A

Phase 3

24
Q

Which antiarrhythmics have the highest risk of causing torsades?

A

Class 3

25
Q

MOA of class 3?

A

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

26
Q

Drugs in class 3

A

Amiodarone, Ibutilide, Dofetilide, Sotalol

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27
Q

Most efficacious of all antiarrhythmics?

A

Amiodarone

Has groups 2 and 4 activities too

28
Q

MOA of class 4

A

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

29
Q

Amiodarone side effects, toxicity

A

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

30
Q

Why are dihydropyridine CCBs not useful as antiarrhythmics ?

A

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

31
Q

Examples of class 4 drugs

A

Verapamil, diltiazem

32
Q

DOC for paroxysmal SVT?

A

Adenosine- miscellaneous antiarrhythmics

33
Q

Miscellaneous antiarrhythmics

A

Adenosine, potassium ion, magnesium ion

34
Q

Beta blocker that lacks local anesthetic effect

A

Timolol

35
Q

Class 3 acts on what phase of AP?

A

Phase 3

36
Q

Which antiarrhythmics have the highest risk of causing torsades?

A

Class 3

37
Q

MOA of class 3?

A

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

38
Q

Drugs in class 3

A

Amiodarone, Ibutilide, Dofetilide, Sotalol

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39
Q

Most efficacious of all antiarrhythmics?

A

Amiodarone

Has groups 2 and 4 activities too

40
Q

MOA of class 4

A

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

41
Q

Amiodarone side effects, toxicity

A

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

42
Q

Why are dihydropyridine CCBs not useful as antiarrhythmics ?

A

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

43
Q

Examples of class 4 drugs

A

Verapamil, diltiazem

44
Q

DOC for paroxysmal SVT?

A

Adenosine- miscellaneous antiarrhythmics

45
Q

Miscellaneous antiarrhythmics

A

Adenosine, potassium ion, magnesium ion

46
Q

Increase QRS duration

A

class 1C

47
Q

Beta blockers with partial agonist activity

A

Pindolol, acetabulol

48
Q

Prolongs PR interval

A

Class 2 and class 3