Antiarrhythic Drugs Flashcards
Phase 0 action potential
Na+ enters the cell depolarization
Phase 2 action potential
Ca2+ enters cell
Initiation of contraction
Phase 3 action potential
K+ exits cell
Repolarization
Quinidine =
Uses:
Mechanism:
Adverse effect:
Metabolism:
Class 1a
Atrial fibrillation, ventricular tachycardia
Brugada Syndrome, Early Repolarization Syndrome
Blocks fast inward sodium channel
Use-dependent = more block w/ faster heart rates
Prolongs action potential duration and QT interval –> risk of fatal arrhythmias
Diarrhea, thrombocytopenia, hepatitis
Liver - cytochrome p450
Procainamide =
Uses:
Mechanism:
Adverse effect:
Metabolism:
Class 1a
Atrial fibrillation, ventricular tachycardia (formerly)
Wolff-Parkinson-White Syndrome, VT storm
Sodium channel blocker AND blocks outward potassium channels
Rashes, myalgia, lupus
Renal
Disopyramide =
Use:
Mechanism:
Adverse effect:
Metabolism:
Class 1a
- Women over 40 y/o w/ atrial tachyarrhythmias
- Atrial fibrillation (hypertrophic cardiomyopathy)
- Increase SA and AV nodes (vagolytic): pt with atrial fibrillation already have slow heart rate. This drug is good b/c it doesn’t slow heart rate down slower.
Sodium channel blocker
Dry mouth, blurred vision, constipation, urinary retention
Renal
Lidocaine =
Use:
Adverse effect:
Metabolism:
Class 1b
Only IV
Used adjunct w/ Amiodarone or Sotalol in ventricular arrhythmias
Shortens QT interval
Narrow therapeutic range: very easy to get toxicity (neurologic)
Liver
Mexilitene =
Use:
Adverse effect:
Metabolism:
Class 1b
Use w/ Amiodarone or Sotalol
Transition from lidocaine
Automatic ventricular arrhythmias (ILVT, RVOT, LQT)
Shortens QT interval
GI irritation: take w/ meals
Liver
Propafenone =
Mechanism:
Use:
Adverse effect:
Metabolism:
Class 1c
Sodium channel blocker (use-dependent)
Atrial arrhythmia in women
Raise INR in pts on warfarin
Metallic taste, constipation
Beta blocking –> don’t use w/ asthma and Raynaud’s Syndrome
Liver
Flecainide =
Mechanism:
Uses:
Adverse effect:
Metabolism:
Class 1c
Sodium channel blocker (use dependent)
Healthy people (NO CHF or CAD) Premature Atrial Contraction Premature Ventricular Contraction Outflow tract arrhythmias AFib
Do NOT use with flutter
Primarily renal, some hepatic
Sotalol =
Mechanism:
Uses:
Class 3
Potassium channel blocker + beta blocker
Low dose (80mg): B-blocker effect
High dose: potassium channel effect
Careful in women
Good in men already on B-blocker
Afib, VT, VT Storm
Dofetilide =
Mechanism:
Use:
Complications:
Class 3
Potassium channel blocker
Afib, atrial tachyarrhythmia
Lots of drug interactions
Need to be in hospital to start
Dronedarone =
Uses:
Class 3
Only Paroxysmal AF
Not potent
Amiodarone =
Uses:
Toxicities:
Class 1,2,3 and Ca2+ blocking properties
AFib, VT
Predictable toxicities: lungs, thyroid, liver, retina
Monitor w/ DLCO, liver enzymes, FT4/TSH, eyes
Ranolazine =
Antianginal drug
Sodium, potassium, calcium channel blocker
Ventricular arrhythmias in ICD patients Atrial fibrillation (trial)
