Pharm 11- Antiarrhythmics Flashcards Preview

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Flashcards in Pharm 11- Antiarrhythmics Deck (85)
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1

Arrythmia

abnormalities in the electrical impulse generation of conduction through the heart

2

What percent of anesthetized patients have arrythmias?

>50%

3

What percent of patinets with MIs have arrhythmias?

80%

4

How do virutally all antiarrythmics work?

Altering the ionic transmembrnae balance (Na+ Ca++, K+) or the sympathetic tone to the heart; which alters the shape of the action potential

5

What is the name of the classification system that classifies 4 types of antiarrhythmics?

The Vaughan Williams Classification

6

What classes are Na+ channel blockers?

1A, 1B, 1C

7

What class is B-Blockers?

2

8

WHat class is K+ blocker?

3

9

What class is Ca++ channel blocker?

4

10

How does class IA work on the action potential?

Slows phase 0 depolarization in ventricular muscle fibers

11

How does class IB work on the action potential?

Shortens Phase 3 repolarization in ventricular muscle fibers

12

How does class IC work on the action potential?

Markely slows phase 0 depolarization in ventricular muscle fibers

13

How does class II work on the action potnetial?

Inhibits phase 4 depolarization in SA and AV nodes

14

How does class III work on the action potential?

Prolongs phase 3 repolarization in ventricular muscle fibers

15

How does class IV work on the action potential?

Inhibits action potential in SA and AV nodes

16

How do Class I: Na+ Channel Blockers work?

Preferentially bind to open Na+ channels rather than to fully repolarization Na+ channels; preferentially block conduction in tssues that are depolarizing more frequently (use-dependence blockade)

17

Use-Dependence Blockade

preferentially blocking conduction in tissues that are depolarizing more frequently; used in Class I: Na + channel blockers

18

How are the 3 subclasses of Class I antiarrythmics differentiated?

Ia: Shorten the AP and affect QRS
Ib: Shortern the AP w/o affecting QRS
Ic: Does not shorten the AP

19

Which Class is nicknamed "Membrane stabilizers?"

Class Ia: Na+ Channel Blockers

20

How do Class Ia: Na+ Channel Blockers shift the action potential?

Shift to the right by slowing Phase 0 depolarization; hence their nickname "membrane stabilizers"; also inhibits some K+ channels (class III activitY) which widens the AP causing prolonged QT intervals

21

How do Class Ia: Na+ Channel Blockers widen the AP causing prolonged QT intervals?

They inhibit some K+ channels (class III activitY)

22

What is the pneumonia to remember Ia drugs?

Double Quarter Pounder

23

What are the three Class Ia drugs?
Double Quarter Pounder

Disopyramide (Norpace)
Quinidine (Quinidex)
Procainamide (Pronestryl, Procan)

24

Quinidine (Quinidex)

Administered Orally
Various tachyarrhythmias, but rarely used due to toxic side effects: Cinchonism/Torsades de Pointes

25

Cinchonism

poisoning due to excessive ingestion of cinchona alkaloids; unclear vision red skin vomiting vertigo diarrhea

26

Torsades de Pointes

Polymorphic Ventricular Tachycardia
usually resolves spontaneously; may devolve in to V-fib

27

Dispyramide (Norpace)

More negative inotropic effects and increase SVR than Quinidine (Quinidex); could precipitate HF
3-4th line antiarrythmic

28

What is the most widely used Ia: Na+ channel blocker?

Procainamide (Pronestryl, Procan)

29

Procainamide (Pronestryl, Procan)

most widely used Ia
Derived from procaine (anesthetic)
Given orally IV, IM
Adverse effects similar to Quinidine (although less severe) but may cause reversible lupus erythematosus

30

Reversible Lupus Erythematosus

Autoimmune disease; Neurologic manifestations are among the features of systemic lupus erythematosus (SLE), a multisystem autoimmune connective tissue disorder with various clinical presentations. SLE affects many organ systems, including the central and peripheral nervous systems and muscles