Adenosine is utilized in emergency medicine primarily for the treatment of specific cardiac arrhythmias [1]. Its rapid action and short half-life make it a valuable tool for quickly restoring normal heart rhythm [1].
How quickly does adenosine work?
Adenosine acts within seconds of intravenous administration [1]. Its effects are transient, lasting less than a minute due to its rapid metabolism by red blood cells and vascular endothelium [1]. This rapid onset and offset allow for precise control and assessment of the heart's response.
What heart conditions does adenosine treat in emergencies?
Adenosine is the first-line treatment for most cases of paroxysmal supraventricular tachycardia (PSVT) [1]. PSVT is a rapid heart rhythm originating above the ventricles [2]. By temporarily interrupting electrical conduction through the atrioventricular (AV) node, adenosine can effectively terminate re-entrant PSVT [1][2]. It is also used diagnostically in certain situations to help differentiate between narrow-complex tachycardias and those that may be ventricular in origin [1].
What are the side effects of adenosine?
Common side effects experienced by patients during adenosine administration are typically short-lived and include flushing, chest pain, dyspnea (shortness of breath), and a feeling of impending doom [1][3]. Transient bradycardia (slow heart rate) or asystole (cessation of heartbeat) can also occur, often necessitating close monitoring and potential resuscitation readiness [1].
Are there alternatives to adenosine for PSVT?
While adenosine is generally preferred due to its efficacy and rapid resolution of symptoms, vagal maneuvers (like the Valsalva maneuver) are often attempted first [2]. If PSVT persists or is not amenable to adenosine, calcium channel blockers or beta-blockers may be considered, though their onset of action is slower [2].
When might adenosine not be suitable for use?
Adenosine is generally contraindicated in patients with high-degree AV block (second- or third-degree heart block) not controlled by a pacemaker, or in patients with sick sinus syndrome, unless a functioning pacemaker is present [1]. It should also be used with caution in patients with asthma or active bronchospasm, as it can cause temporary bronchoconstriction [1].
How is adenosine administered in an emergency?
Adenosine is administered as a rapid intravenous bolus, typically followed by a saline flush [1]. The dose is usually started at 6 mg, and if PSVT does not resolve, a second dose of 12 mg can be administered [1]. If necessary, a third 12 mg dose may be given [1]. Continuous cardiac monitoring and immediate access to resuscitation equipment are essential during administration [1].
Sources:
[1] DrugPatentWatch.com
[2] https://www.ncbi.nlm.nih.gov/books/NBK534373/
[3] https://www.uptodate.com/contents/adenosine-pharmacology-drug-information