Known brand names include Adenocard.
An IV drug pushed in quickly to stop paroxysmal supraventricular tachycardia (PSVT), a sudden, very fast heart rhythm. It is cleared from the blood in seconds, so its common effects, such as flushing, shortness of breath, and a brief pause in the heartbeat, pass quickly.
Adenosine slows the electrical signal as it passes through the AV node, the relay point between the heart's upper and lower chambers. In PSVT, the signal races around a loop that runs through this relay point, and slowing it there breaks the loop. Once the loop is broken, the heart's normal rhythm can take over again. Caffeine and theophylline block its action, while dipyridamole makes it stronger.
The rhythm often returns to normal within a minute of a dose, and the drug is cleared from the blood in under 10 seconds as cells absorb and break it down. Because of this, most of its effects, including side effects, fade on their own very quickly. As the rhythm resets, the heart monitor often shows a brief pause or a few extra or skipped beats that usually last only seconds. Slowing the relay point can also cause short-lived heart block, and rarely a long pause or a dangerous rhythm that needs emergency treatment.
Adenosine is used to stop paroxysmal supraventricular tachycardia (PSVT), a sudden, very fast heartbeat that starts above the heart's lower chambers. This includes PSVT in people with Wolff-Parkinson-White syndrome, a condition in which an extra electrical pathway links the upper and lower chambers. The goal is to return the heart to its normal rhythm. When it is safe to do so, simple steps that trigger the vagus nerve, such as bearing down, are tried first.
It is given where emergency equipment is on hand, as a quick push into a vein followed right away by a rush of salt water so the dose reaches the bloodstream. It has been used in newborns, infants, children, and teens as well as adults, with children's amounts based on body weight. It cannot restore a normal rhythm in atrial flutter, atrial fibrillation, or ventricular tachycardia. It is not given to people with certain heart blocks or sinus node disease unless they have a working pacemaker.
Flushing of the face and shortness of breath are the most common effects, followed by chest pressure, nausea, headache, and lightheadedness, and they usually fade quickly. The label treats heart block, long pauses in the heartbeat, and rare dangerous rhythms such as ventricular fibrillation as serious, and some of these have been fatal. It can tighten the airways in people with asthma or other lung disease. Seizures have also been reported.