III. Contraindications

  1. QTc Prolongation (or QT >500 msec)
  2. Severe Left Ventricular Dysfunction
  3. Combination with Class 1a or Class III Antiarrhythmics

IV. Mechanism

  1. Class III Antiarrhythmic

V. Precautions

  1. Cardiac monitoring on starting Ibutilide
    1. Monitor for a minimum of 4 hours after drug administration
    2. Continue monitoring until QTc Interval normalizes
  2. Correct Electrolyte abnormalities before starting Ibutilide (and continue to monitor Electrolyte levels)
    1. Serum Potassium
    2. Serum Magnesium

VI. Dosing

  1. Initial
    1. Weight <60 kg: 0.01 mg/kg IV over 10 min
    2. Weight >60 kg: 1 mg IV over 10 min
  2. Subsequent
    1. May repeat once after 10 min if not converted to sinus rhythm with first dose
    2. Stop infusion on conversion to sinus rhythm

VII. Adverse Effects

  1. Significantly proarrhythmic
    1. Ventricular Tachycardia or fibrillation risk: 1-2%
    2. Requires EKG monitoring for 4 hours after dose
  2. Prolonged QTc
    1. Risk of Torsades de Pointes
    2. Observe in monitored setting

VIII. Efficacy

  1. Atrial Fibrillation Cardioversion
    1. Time to Cardioversion: 1 hour
    2. Conversion Rate: 33-45% (60% in Atrial Flutter)

IX. Safety

  1. Unknown safety in Lactation
  2. Pregnancy Category C

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