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Pharm Block 2 > Antiarrhythmic Drugs > Flashcards

Antiarrhythmic Drugs Flashcards

1
Q

What are the phases of cardiac cycle (0,2,3,4)

A

Phase 0 - depolarization. Na+ entering the cell
Phase 2 - More potassium leaving the cell than Calcium coming in, leading to plateau
Phase 3 - Much more potassium leaving, repolarization
Phase 4 - Ready for depolarization in non-pacemaker cells, pacemaker cells depolarizing

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2
Q

How do you treat bradyarrthymias?

A

Atropine + Beta agonist

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3
Q

What are afterdepolarizations? What can they cause?

A

These occur when abnormal calcium influx into cardiac cells during or immediately after Phase 3 of ventricular action potential. May lead to extra systoles and tachycardia.

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4
Q

What is the mechanism of the Class IA antiarrhythmics?

A

Sodium channel blockers, these decrease automaticity and prolong refractory period

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5
Q

Name the 3 Class IA drugs?

A

Procainamide, Disopyramide, Quinidine

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6
Q

What is a negative side effect of Procainamide?

A

Causes Lupus erthyremotosis, reversible

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7
Q

What is a side effect of quinidine?

A

cinchonism - tinnitus

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8
Q

What is the most powerful Class I A drug?

A

Disopyramide, decreases contractility the most so most likely to cause HF.

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9
Q

What are the side effects of the Class I A drugs?

A

Ventricular tachycardia, syncope, AV block, decreased contractility leading to HF, Decreased blood pressure due to vasodilation of vascular smooth muscle (lack of sodium)

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10
Q

What is the mechanism of the Class IB antiarrythmics?

A

These shorten the duration of the action potential, shortening the refractory period. Still sodium channel blockers.

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11
Q

Name the Class IB drugs?

A

Lidocaine, Tocainide, Mexiletine, Phenytoin

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12
Q

What is significant about Lidocaine?

A

number 1 drug used to treat arrthymias. Acts as a local anesthetic. Effects takes about one hour.

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13
Q

What are the longer acting Class IB drugs?

A

Tocainide and Mexiletine (also used to treat pain from diabetic neuropathy). These last about half a day.

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14
Q

What is Phenytoin used to treat?

A

Digitalis-induced arrthymias, anticonvulsant

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15
Q

What are side effects of Class I B?

A

Tremors, convulsions, slowed AV nodal conduction velocity which can cause heart block

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16
Q

What are the Class 1C Antiarrhythmics?

A

These are sodium channel blockers with no effect on action potential.

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17
Q

Name the Class IC drugs?

A

Flecainide, Propafenone. Side effects: proarrhthmogenic, hyperkalemia increases cardiotoxicity.

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18
Q

What is the mechanism of the Class II antiarrhythmics?

A

These are Beta Blockers, Slow Phase 4 depolarization. High doses block sodium channels.

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19
Q

Name the 4 Class II drugs used?

A

Propranolol, Acebutolol, Esmolol, Sotalol

20
Q

What is the most important effect of Class II Antiarrythmics?

A

Only class of drugs used to reduce/prevent sudden death from myocardial infarction.

21
Q

What are Class II antiarryhthmics used for?

A

Sympathetic-induced tachycardia, paroxysmal supraventricular tachycardia, a-flutter and a-fib, prophylaxis post-MI to prevent sudden death

22
Q

What are the B1 selective Class II antiarrhythmics?

A

Esmolol and Acebutolol. Esmolol used in OR for anesthesia induced arrhythmias.

23
Q

What is Sotalol?

A

Class II Beta Blocker. Racemic mixture, L-isomer is Beta Blocker and D-isomer is Potassium Channel Blocker.

24
Q

What are the side effects of Class II drugs?

A

Decreased HR and conduction, sedation, asthma for non-selective, HF, sexual dysfunction, and decrease in CO.

25
Q

What are the Class III antiarrhythmics?

A

Potassium channel blockers, block exit of potassium from the cell. Prolong action potential, effective refractory period and repolarization. Slows cells down.

26
Q

When do you use the Class IIIs

A

When ventricular arrhythmias refractory to other types of therapy

27
Q

What is Amiodarone?

A

Class III, K+ channel blocker, but also blocks sodium and calcium channels. Can cause thyroid dysfunction and deposit metabolites in lens/cornea.

28
Q

What is a major (problematic) side effect of Class III antiarythmics?

A

can produce torsades de pont

29
Q

What are the 4 class III drugs?

A

Amiodarone, d-Sotalol, Ibultilide, Dofetilide

30
Q

What is important to remember about Dofetilide?

A

requires certification for doctor and hospital because of high toxicity

31
Q

What is ibutilide used to treat?

A

Convert A flutter and A fib to normal, sinus rhythm. Highly arrtyhmogenic. single injection.

32
Q

What are class IV antiarryhthmics?

A

Calcium channel blockers (L-type). Reduce calcium entry during action potential and during Phase 4. Conduction velocity slows, refractory period prolongs.

33
Q

Which calcium channel Blockers ARE NOT USED for arrthymias?

A

Dihydropyridine calcium channel blockers

34
Q

Which Class IV drugs are used in arrythmias?

A

Verapamil, Diltiazem, Bepridil

35
Q

What is a serious side effect of Verapamil?

A

can increase serum digoxin concentrations

36
Q

Which drugs causes constipation in the Class IVs?

A

Verapamil

37
Q

What condition do you avoid Class IVs?

A

Wolff-Parkinson White syndrome.

38
Q

When is adenosine used?

A

during life threatening ventricular arrhythmias and paroxysmal supraventricular tachyarrythmias including Wolff-parkinson white. Stops the heart for 5-10 seconds.

39
Q

When do you give magnesium?

A

torsades de pointes, MI, cardiac arrest with suspected hypomagnesia.

40
Q

What are the effects of hypokalemia and hyperkalemia on arrhytmias?

A

Hypokalemia increases risk, which hyperkalemia decreases conduction and causes re-entry type arrthymias.

41
Q

What is the only antiarrtymic that doesn’t become arrhtyhmogenic at higher doses?

A

amiodarone

42
Q

How do you treat atrial flutter?

A

Beta blocker, Calcium channel blocker, Digoxin

43
Q

How do you treat A fib?

A

Beta blocker, Potassium channel blocker (amiodoraone - also blocks Ca2+ and Na+)

44
Q

How do you treat AV Nodal re-entry

A

beta blocker, calcium channel blocker, digoxin

45
Q

How do you treat acute SVT

A

adenosine

46
Q

How do you treat acute VT

A

Lidocaine, amiodorone

47
Q

How you treat Vfib?

A

Amiodorone, epi

Pharm Block 2 (5 decks)

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