ADENOSINE

Adenocor

 Reviewed by Dr Pat Clarkson, Robyn Wilkinson, Brenda Hughes, Lejla Brkic
January 1999
Reviewed By Dr Jon Skinner, October 1999
Administration Newborn Drug Protocol Index Newborn Services Home Page

Dose and Administration

  1. Initial dose 0.05 – 0.10 mg / kg  7 , 8
  2. Increase by 0.05mg/kg/dose to a maximum of 0.25mg/kg/dose (this is likely to be effective in 90% of cases)
  3. Administered by direct IV injection over 1-2 seconds followed by a rapid sodium chloride 0.9% flush.

Indications

  1. Diagnosis and treatment of tachyarrhythmias
  2. Other antiarrhythmic medication may be required to prevent recurrence of tachyarrhythmias

Precautions

  1. Not usually advisable with second or third degree AV block, or sinus node dysfunction
  2. Caution in patients capable of rapid AV conduction.
  3. Adenosine may be a mild bronchoconstrictor. Caution may be required in patients with a tendency to bronchoconstriction. However, adenosine does have a half-life of less than 10 seconds.

Drug Interactions

A drug interaction may occur when a baby is taking other drugs concomitantly.

Adenosine +:

Caffeine, Theophylline, Aminophylline

An increase in the adenosine dose may be required 1 .The methylxanthines may oppose the antiarrhythmic effects of adenosine by their antagonistic effect on adenosine receptors.

Beta blockers

Not used concomitantly without specialist consultation

Clinical Pharmacology

Adenosine depresses conduction through the AV node. This action can interrupt re-entry circuits involving the AV node and restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia. It does not have a negative inotropic action.

Adenosine is an endogenous nucleoside primarily formed as a degradation product of adenosine triphosphate. As an intermediate metabolite in several biochemical pathways, adenosine contributes to the regulation of numerous physiologic processes, including platelet function, coronary and systemic vascular tone, and lipolysis in adipocytes. The duration of electrophysiologic and clinical effects are extremely short, < 10 seconds. Adenosine is rapidly taken up by most types of cells including cellular elements of the blood and vascular endothelium, where it is rapidly degraded by deamination to inosine and subsequently to hypoxanthine. Total clearance from plasma occurs within < 30 seconds.

Possible Adverse Effects

  1. Atrial fibrillation or atrial flutter with rapid ventricular rate
  2. Bradycardia, varying degrees of AV block, premature ectopic beats.
  3. Dyspnoea, (frequent but transient).
  4. Flushing, (common).
  5. Chest pain in children and adults
  6. Apnoea (rare) 7

Special Considerations

  1. Ideally administered via a central venous line or large peripheral vessel.
  2. Administration through an umbilical artery catheter should be discouraged as the drug is metabolised systemically and metabolised prior to delivery to the heart.
  3. Once the effects of adenosine have been noted, it is usually necessary to institute long term anti arrhythmic therapy.