Thread by @IM_Crit_

ICU/CCU/Pharmacy pearls: Adenosine is another one of my favorite drugs (again: no COI); who doesn’t want to walk into a patient’s ward room after a rapid response is called for a HR of 190/min, administer 6 mg of adenosine and head back to the ICU 10 min later leaving the patient

on SR 80/min and the ICU charge nurse relieved that she will not have to find a creative way to “open up” another ICU room. Adenosine push is one of the VERY FEW intensivists’ triumphant moves, so I will take it. Nevertheless, there are a few things about adenosine use

that I think are fun or good to know (there are probably more than few, I just don't know them!):
1. Adenosine is a natural substance formed by the degradation of adenosine triphosphate (ATP); yes, that ATP! So, in theory

u can push ATP to stop an arrhythmia (if u find yourself in a MacGyver scenario…) but I think adenosine is more stable at room temp and this is why it is preferred over ATP
2. Adenosine should be stored below 25°C but it should not be refrigerated. I believe it gets crystallized

3. Everybody knows that adenosine should be given as a rapid iv bolus (over 1-2 sec) followed immediately by saline flush. This is NOT dictated by the urgency of the situation but by the drug’s PK/PD properties. Its half-life is < 10 seconds due to rapid metabolism by RBCs

(remember esmolol?). For this reason, some people even argue that besides rapid bolus/NS flush & keeping the arm above the heart level, we should make sure that there is no blood in the syringe & the most central vein is used (use the one in the elbow, not the one on the thumb!)

4. If the patient is on dipyridamole or has undergone a heart transplant, the dose of adenosine should be reduced (start w 3 mg instead of 6). On the other hand, xanthine derivatives (theophylline) show a dose-dependent blockade of adenosine receptors and a higher dose of

adenosine (12+ mg) is usually required. I see heart transplant patients very very rarely, I see patients on theophylline infrequently and last time I took care of someone on dipyridamole, it was > 10 years ago (maybe more…). A bit esoteric things to remember but important IMHO

5. Dyspnea and chest pressure are VERY common. ALWAYS inform your patient beforehand that she may feel weird…
6. It is very well known that adenosine is almost always effective in terminating supraventricular tachycardia in which the AV node is part of the circuit while the

vast majority of ventricular tachycardias are insensitive to adenosine. What it is less known is the fact that adenosine CAN induce atrial fibrillation in 10-15% of patients. Adenosine has been associated in some cases with ventricular pre-excitation and hemodynamic collapse.

The shortening of the atrial action potential and refractory period and the induction of frequent ectopic complexes seem to be the factors leading to atrial fibrillation.
7. Adenosine, especially if you use higher does, can cause asystole. And sometimes this is desirable. What?

Well, adenosine-induced asystole can facilitate cerebral aneurysm clipping, endovascular embolization of a cerebral arteriovenous malformation and stent implantation in thoracic aorta endovascular surgery.

8. In any case, whenever you push adenosine, it is extremely important that you keep the patient under continuous ECG monitoring and the code cart at the bedside.

Thanks for reading!

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