Antiarrhythic Therapy Flashcards

1
Q

Anti-arrhythmic agents

A

1a) quinidine, procainamide, disopyramide
1b) mexilitene, didocaine
1c) flecainide, propafenone
III) sotalol, dofetilide, dronedarone, ibutilide (channel blockers)
- amiodarone, ranolazine

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2
Q

Ia - Quinidine

A
  • stereo isomer of quinine, derived from cinchona tree
  • blocks fast inward Na+ channel: use dependent=more block w/ faster heart rate, prolongs action potential duration & QT interval (not good)
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3
Q

Ia - Quinidine: reason for decreased usage

A
  • used for Afib & ventricle tachycardia till 1990s

- caused diarrhea, thrombocytopenia, hepatitis, TORSADES DE POINTES due to QT prolongation

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4
Q

Ia - Quinidine: new uses

A
  • brugada syndrome & early repolarization syndrome
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5
Q

Ia - Quinidine: metabolism

A
  • live metabolism: cytochrome p450
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6
Q

Ia - procainamide

A
  • uses: Afib, Wolff-Parkinson White Syndrome, VT “Storm”
  • sodium channel blocker but also blocks outward potassium channels
  • can cause rashes myalgias, lupus
  • Renal Metabolism
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7
Q

Ia - Disopyramide

A
  • sodium channel blocker
  • VAGOLYTIC: speeds up heart, UNLIKE other channel blockers
  • uses: Afib especially in HCM
  • anticholinergic side effects: dry mouth, blurred vision, constipation, urinary retention (used less in older men)
  • Renal Excretion
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8
Q

Ib - Lidocaine

A
  • ONLY IV
  • NARROW therapeutic range
  • useful as adjunct to amiodarone or sotalol in ventricular arrhythmias
  • shortens QT
  • LIVER metabolized
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9
Q

Ib - Mexilitene

A
  • good agent to use w/ amiodarone or sotalol (transition from lidocaine)
  • shortens QT
  • pretty much ORAL form of lidocaine
  • uses: ventricular arrythmias (TAKE WITH MEALS)
  • LIVER metabolized
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10
Q

Ic - Propafenone

A
  • sodium channel blocker: use dependent

- good Afib med in WOMEN

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11
Q

Ic - Propafenone: adverse effects

A
  • metallic taste, constipation
  • some B-blocking properties so can be a problem in asthma & Raynaud’s Syndrome
  • CAN RAISE INR IN PATIENTS ON WARFARIN
  • MEN get more side effects
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12
Q

Ic - Propafenone: metabolism

A

LIVER

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13
Q

Ic - Flecainide

A
  • sodium channel blocker: use dependence

- great drug in HEALTHY PEOPLE

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14
Q

Ic - Flecainide: when & when not to give

A
  • uses: PACs, PVCs, outflow tract arrhythmias, Afib

- don’t give: CHF, CAD, FLUTTER

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15
Q

Ic - Flecainide: metabolism

A
  • primary renal, some hepatic (p450)
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16
Q

III - Sotalol

A
  • potassium channel blocker + B-blocker
  • careful in women: late torsades (renal metabolism varies)
  • good drug in men already on B-blocker
  • uses: Afib, VT, VT Storm
17
Q

III - Dofetilide

A
  • potassium channel blocker
  • must ADMIT TO HOSPITAL to start
  • many drug interaction limit usefulness except in HEALTHY PEOPLE
  • uses: Afib
18
Q

III - Dronedarone

A
  • hyped to be amiodarone w/ out toxicites
  • nowhere near as potent
  • ONLY indicated for PAF
19
Q

Amiodarone

A
  • Class I, II, II, and Ca++ blocking properties
  • BEST DRUG FOR AFib, VT
  • toxicities: lungs, thyroid, liver, retina
  • CAN EFFECT INR FOR THOSE ON WARFARIN
20
Q

Ranolazine

A
  • developed as antianginal drug
  • sodium, potassium, calcium channel blocking properties
  • RAID Trial: ranolazine to treat VTs in ICD patients
21
Q

Mechanisms of antiarrhythmias

A
  • automatic: pebble in pond, single focus w/ out circuit

- re entrant: circuit involved