Regadenoson for vasodilator myocardial stress – selective A2A receptor agonist

Regadenoson for vasodilator myocardial stress – selective A_2A receptor agonist

Regadenoson for vasodilator myocardial stress: Regadenoson, adenosine and dipyridamole are the three vasodilators which can be used during radionuclide myocardial perfusion imaging. Their response is mediated through adenosine receptors: A₁, A_2A, A_2B and A₃.  A_2A receptor activation leads to coronary vasodilation [1] and some peripheral vasodilation. A₁, A_2B and A₃ activation are responsible for bronchospasm and high grade AV block. Regadenoson is a selective A_2A receptor agonist while adenosine binds to all of them non selectively. Dipyridamole acts by reducing the metabolic degradation of adenosine and has an effect on all the adenosine receptors.

United States Food and Drug Administration (FDA) approved regadenoson in myocardial perfusion studies in 2008 [1]. Regadenoson is given as a single intravenous bolus through peripheral vein. There is no need for dose adjustment in renal failure. Regadenoson produces rapid coronary vasodilatation and flow increases to more than 2.5 times baseline. The effect is sustained for 2.3 minutes. Then it decreases to fall below twice the baseline value in 10 minutes.

Regadenoson has been rarely reported to cause seizures [2].

References

1. Shinro Matsuo. Editorial: Regadenoson: An Adenosine A 2A Receptor Agonist for Pharmacological Myocardial Perfusion Imaging. J Cardiol Cases. 2014 Apr 19;10(2):46-47.
2. Robert Lee Page 2nd, Patrice Spurck, Jacquelyn L Bainbridge, Julie Michalek, Robert A Quaife. Seizures Associated With Regadenoson: A Case Series. J Nucl Cardiol. 2012 Apr;19(2):389-91.