AMIODARONE HYDROCHLORIDE

Cordarone X

 Reviewed by Brenda Hughes, Dr Carl Kuschel, Dr Jon Skinner (Paediatric Cardiology) and Karen Anderson-Hawke (NS-ANP)
June 2005
Administration Newborn Drug Protocol Index Newborn Services Home Page

Dose and Administration

Intravenous 1,2

  1. Loading dose: 25 microgram/kg/minute for 4 hours, then
    Maintenance dose: 5 to 15 microgram/kg/minute

Oral  1,2 

  1. 4mg/kg/dose every 8 hours for one week, then
  2. 4mg/kg/dose every 12 hours for one week, then
  3. 4mg/kg/dose once daily.

Note: if converting from IV infusion to oral dosing, use 4mg/kg/dose and consult cardiologist for oral dose frequency.

Indications

  1. Control of ventricular and supraventricular arrhythmias including those associated with Wolff-Parkinson-White syndrome.

Contraindications

  1. Hypersensitivity to amiodarone or iodine.
  2. Sinus bradycardia.
  3. Sino-atrial heartblock.
  4. Severe respiratory failure.
  5. >Circulatory collapse, severe systemic hypotension, cardiogenic shock, 2nd or 3rd degree AV block.

Precautions

  1. Hepatic disease
  2. Pulmonary disease
  3. Thyroid disorders
  4. Hypotension, AV block, left ventricular dysfunction, heart failure, bradycardia, myocardiopathy
  5. Electrolyte imbalance
  6. Preterm infants less than 32 weeks gestation (the injection contains benzyl alcohol which was associated with the “gasping syndrome” with symptoms of hypotension, bradycardia, gasping respiration, cardiovascular collapse and death).

Drug Interactions

Digoxin
  • Reduce digoxin maintenance dose by half. If loading digoxin, use a full loading dose, then half maintenance dose. Monitor digoxin levels.
Flecainide
  • Use carefully. Reduce flecainide dose.
Diuretics
  • Risk of hypokalaemia.
Corticosteroids
  • Risk of hypokalaemia.
Amphotericin
  • Risk of hypokalaemia.
Phenytoin
  • Monitor phenytoin levels. Phenytoin level may increase and amiodarone decrease
Sotalol
  • Possible increase in QT interval
Erythromycin IV
  • Possible increase in QT interval
Beta-blockers and Calcium Channel Blockers
  • Not recommended with amiodarone because of possible increase in bradycardia, AV block, and myocardial depression.
Anaesthetic agents
  • Use cautiously.

Clinical Pharmacology

Amiodarone is a Class III antiarrhythmic agent. Its broad spectrum of activity is due to prolongation of the action potential duration and refractory period of the atrial, nodal and ventricular tissues. It is extensively distributed into body tissues, accumulating in muscle and fat. Oral absorption is erratic, and may lead to a wide range in bioavailability. Des-ethyl amiodarone is an active anti-arrhythmic metabolite. For both parent drug and metabolite, biliary excretion with some enterohepatic recycling, is the major elimination route; there is very little urinary excretion.

Possible Adverse Effects

Adverse effects are common. Many are dose-related and decrease with a dose reduction. Possible adverse effects include:

  1. Bradycardia, hypotension (possible with rapid infusion rates, or with prolonged use), arrhythmias, heart failure.
  2. Fatigue, peripheral neuropathy, tremor.
  3. Nausea, vomiting, constipation.
  4. Corneal deposits, visual disturbances.
  5. Photosensitivity, blue-grey discolouration of the skin.
  6. Hepatotoxicity, pulmonary toxicity.
  7. Hypothyroidism or hyperthyroidism due to iodine content of injection.
  8. Venous irritation (when administered peripherally at concentrations > 2mg/ml.).

Special Considerations

  1. Reduce dose in liver disease.
  2. Administration via a central venous catheter is recommended. Can be administered via a peripheral line.
  3. Monitor:
    1. Magnesium, potassium – take baseline levels.
    2. LFTs, thyroid function – take baseline levels.
    3. INR.
    4. ECG and pulse oximetry – monitor continuously.
    5. Perform daily 12-lead ECG (for QTc interval).