anti arrhythmic therapy

  1. quinidine
    • Ia agent
    • blocks fast inward Na+ channel
    • use-dependent: more block with faster heart rate
    • prolongs AP duration and QT interval
    • was primarily used for atrial fibrillation and ventricular tachycardia; now used for Brugada syndrome and early depolarization syndrome
    • adverse effects: diarrhea, thrombocytopenia, hepatitis, QT prolongation (low therapeutic window)
    • metabolized: liver - cytochrome p450
  2. procainamide
    • Ia agent
    • primarily Na+ channel blocker, also blocks outward K+ channels
    • was used to treat atrial fibrillation and ventricular tachycardia; now used to treat acute atrial fibrillation, especially in Wolff-Parkinson-White syndrome and VT storm
    • adverse effects: rashes, myalgia, lupus
    • metabolized: renal
  3. disopyramide
    • Ia agent
    • Na+ channel blocker
    • vagolytic - can increase SA and AV nodes = good in patients who are bradycardic
    • used to treat atrial fibrillation, especially in hypertrophic cardiomyopathy
    • adverse effects: anticholinergic - dry mouth, blurred vision, constipation, urinary retention
    • renal excretion
  4. lidocaine
    • Ib agent
    • only IV
    • narrow therapeutic range
    • useful as adjunct to amiodarone or sotalol in acute setting for ventricular arrhythmias
    • shortens QT interval
    • liver metabolized
    • toxicities mainly neurologic
  5. mexilitene
    • Ib agent
    • good agent to use with amiodarone or sotalol - transition from lidocaine
    • shortens QT interval
    • useful in automatic ventricular arrhythmias
    • adverse effects: mainly GI irritation (MUST TAKE WITH MEALS)
    • liver metabolized
  6. propafenone
    • Ic agent
    • NA+ channel blocker - use-dependence
    • good atrial arrhythmia med in women
    • side effects: metallic taste, constipation
    • β-blocking properties and can be a problem in asthma and Raynaud's syndrome
    • **Can raise INR in pts on warfarin
    • liver metabolized
  7. flecainide
    • Ic agent
    • NA+ channel blocker with use-dependence
    • great drug in healthy people
    • don't give in heart failure, CAD, for atrial flutters
    • primarily renal metabolism, some hepatic (P450)
  8. sotalol
    • Class III agent
    • K+ channel blocker + β blocker (at low doses i.e. <80 mg 2/day) 
    • careful in women - renal metabolism can vary
    • good drug for men already on β blocker
    • Afib, VT, VT storm
  9. dofetilide
    • Class III agent
    • K+ channel blocker
    • reasonable choice in Afib or other atrial tachyarrhythmias 
    • renal metabolism
    • big drawback: needed admission to start (inpatient), many drug interactions (useful mainly in healthy people who aren't on other meds)
  10. dronedarone
    • Class III agent
    • not as potent as amiodarone, but fewer toxicities
    • indicated only for paroxysmal atrial fibrillation
    • hepatic metabolism (CYP3A)
    • mild class I-II-IV properties
    • some patients do quite well on this
  11. amiodarone
    • has class I, II, III and Ca2+ blocking properties
    • best drug for AFib, VT
    • very predictable toxicities: lungs, thyroid (hyper and hypothyroidism), liver, retina (need to check diffusing capacity, liver enzymes, thyroid, eyes)
  12. ranolazine
    • developed as anti-anginal drug 
    • has Na+, K+, and Ca2+ channel blocking properties
    • ongoing trial looking at use for atrial fibrillation
  13. labetalol
    • β-adrenergic and α1 adrenergic antagonist
    • intrinsic sympathomimetic activity plus alpha blockade
    • underused in HTN
    • used to treat malignant HTN and can be used for pheochromocytoma (want to block α before blocking β)
  14. verapamil
    • CA2+ channel blocker
    • liver metabolized
    • more potent AV nodal blockade than diltiazem (IV form underused)
    • pulmonary-friendly
  15. diltiazem
    • Ca2+ channel blocker
    • renal metabolized
    • IV and PO forms readily available
    • both diltiazem and and verapamil are synergistic with β blockers (allows adding a low dose of another class instead of pushing up the dose of primary agent)
Card Set
anti arrhythmic therapy
MOHD 3 lectures 72-73