Adenosine is nucleoside that forms the backbone for energy substrates like ATP and signal transduction/second messenger systems like cyclic AMP. Clinically, it is used to convert supraventricular tachycardias that involve the atrioventricular (AV) node like certain AV reentrant and AV nodal reentrant tachycardias. This is because adenosine causes a transient block at the AV node via inhibition of the calcium current. Additionally, it is sometimes used to induce coronary vasodilation for percutaneous interventions.
Between my roles in the ICU and OR, I’ve pushed adenosine many times in escalating doses (6 mg, 12 mg, 12 mg). I either use a three-way stopcock on short IV tubing connected to an antecubital peripheral IV to push the medication and immediately flush 20 cc of crystalloid, or even better, mix adenosine with saline in a 20 cc syringe and flush it all together in a single push. Adenosine has a plasma half-life on the order of seconds, so it must be administered in a manner to facilitate rapid transit to the heart. Patients often develop flushing, chest pain, hypotension, shortness of breath, and even a sense of impending doom… along with a short-lived run of asystole.
Side point for the caffeine and biochemistry lovers – adenosine is a neuromodulator that plays a pivotal role in the sleep cycle. Caffeine is structurally similar to adenosine and works as an adenosine receptor antagonist to maintain neuronal activity.
Drop me a comment below with questions! 🙂