Medicine & USMLE

Adenosine (Old)

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Adenosine is an antiarrhythmic drug that is used to treat supraventricular tachycardias (SVTs). By momentarily slowing down conduction in the AV node, adenosine can break aberrant electrical circuits in the heart and convert SVT into a normal heart rhythm (sinus rhythm). Importantly, adenosine has an extremely short half life of less than 10 seconds, and its overall effects only last 10-15 seconds. As such, nurses should administer adenosine quickly via a rapid intravenous (IV) injection. While the action of adenosine only lasts for a few seconds, its side effects are very notable and include transient asystole (temporary stopping of the heart), often accompanied by chest pain (angina), a sense of impending doom, flushing, and shortness of breath (dyspnea).

Key Points

  • Adenosine (Adenocard)
    • Mechanism
      • Antiarrhythmic
        • Slows conduction through the AV node
          • Contraindicated in second- and third-degree heart block
        • Causes arterial vasodilation
    • Clinical Use
      • Supraventricular tachycardia (SVT)
        • First-line drug of choice, especially for paroxysmal SVT
        • Converts SVT to normal sinus rhythm, usually by disrupting timing of reentrant circuits through AV node
        • Administer rapid IV push, followed by saline flush
          • Very short half-life (10 seconds) means full dose must be administered extremely quickly
          • If multiple doses are not successful, adenosine is usually followed by cardioversion
    • Side Effects and Adverse Reactions
      • Transient asystole
        • Chest pain
        • Sense of impending doom
        • Continuous cardiac monitoring and frequent assessment of vital signs
      • Flushing
        • Secondary to vasodilation
      • Dyspnea (Bronchospasm)
        • Secondary to the stimulation of vagal C fibers in the lungs
      • Bradycardia
      • Hypotension
      • Ventricular ectopy (PVCs)
      • Tingling/numbness