Pharm

Flecainide

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Flecainide, Tambocor, Flecainide Overdose, Flecainide Toxicity, Flecainide Poisoning

  • Mechanism
  1. Class Ic Antiarrhythmic Drug
    1. Blocks cardiac Sodium channels
    2. Slows cardiac conduction and decreases cardiac contractility
  1. Time to Cardioversion: 3-8 hours
  2. Conversion Rate: 68-91%
  3. Chronic Efficacy: 40-74%
  • Dose
  1. Load: 300-400 mg orally single bolus dose
  2. Maintenance: 50-150 mg orally twice daily
  • Pharmacokinetics
  1. Oral bioavailability: 90%
  2. Peak: 3 hours after ingestion
  3. Volume of Distribution (Vd): 8 to 9 L/kg (high)
    1. Not dialyzable
  4. Half-Life: 12 to 24 hours
  5. Metabolism: Hepatic
    1. Renal excretion: 30% unchanged
  • Precautions
  1. Narrow therapeutic range
  2. Risk of toxicity (esp. in renal dysfunction)
    1. Acute ingestion >1 gram
    2. Chronic dosing error
  • Adverse Effects
  • General
  1. See general adverse effects above
  2. Seizures
  3. Hypotension
  4. Bradycardia
  5. Wide Complex Tachycardia
  1. See Unknown Ingestion
  2. Bedside Glucose
  3. Basic chemistry panel with Electrolytes
  4. Serum Calcium
  5. Serum Magnesium
  6. Toxicology labs (including Acetaminophen level)
  1. Activated Charcoal in alert patient (no aspiration risk) and within one hour of ingestion
  2. Electrolyte disturbance
    1. Potassium Replacement as needed for Hypokalemia
    2. Magnesium Replacement as needed
  3. Hypotension
    1. Initial
      1. Intravenous Fluids
      2. Norepinephrine for Hypotension refractory to fluids
    2. Refractory Hypotension
      1. Intravenous Lipid Emulsion (Intralipid) 20% 1.5 ml/kg to 100 ml bolus (may be repeated)
      2. Extracorporeal Cardiopulmonary Resuscitation (ECMO)
  4. Wide QRS
    1. Hypertonic Sodium Bicarbonate IV with target pH 7.44 to 7.55
  5. Ventricular Tachycardia
    1. Consider Amiodarone or Lidocaine