Mechanism of Action: Slows conduction through the AV node; can interrupt re-entrant pathways; slows heart rate by acting directly on the sinus pacemaker cells by slowing impulse formation. The drug of choice for re-entry SVT. Can be used diagnostically for stable, wide complex tachycardia of unknown origin after two doses of Lidocaine.
Indications: Conversion of PSVT to sinus rhythm. May convert re-entry SVT due to Wolff-Parkinson-White syndrome. Not effective in converting atrial fibrillation/ flutter or V-tach. Most forms of stable narrow-complex SVT.
Contraindications: Second or third degree AV block (if no pacemaker is present), sick sinus syndrome (if no pacemaker present), bronchoconstrictive or bronchospastic lung disease (asthma, COPD), poison or drug induced tachycardia.
Adverse Reactions/Side Effects: Generally short duration and mild; headache, dizziness, dyspnea, bronchospasm, dysrhythmias, palpitations, hypotension, chest pain, facial flushing, cardiac arrest, nausea, metallic taste, pain in the head or neck, paresthesia, diaphoresis.
Drug Interactions: Methylxanthines (theophylline like drugs) antagonize the effects of Adenosine. Dipyridamole (Persantine) potentiates the effect of Adenosine. Carbamazepine (Tegretol) may potentiate the AV node blocking effect of adenosine.
How Supplied: 3mg/mL in 2mL and 5mL flip-top vials.
Dosage and Administration: Adult: 6mg rapid IV bolus over 1–3 seconds, followed by a 20mL saline flush and elevate extremity. If no response after 1–2 minutes, administer second dose of 12mg rapid IV bolus over 1–3 seconds. Pediatric: Initial dose 0.1 mg/kg rapid IV/ IO push (maximum first dose, 6mg), followed by a 5 to 10mL saline flush. Second dose 0.2 mg/kg rapid IV/IO push (maximum second dose, 12 mg), followed by a 5 to 10 mL saline flush.
Duration of Action: Onset: Seconds. Peak Effect: Seconds. Duration: 12 seconds.
Special Considerations: Pregnancy safety: Category C. May cause bronchoconstriction in asthma patients. Evaluate elderly for signs of dehydration requiring fluid replacement prior to administering adenosine. Short half-life limits side effects in most patients.