REGADENOSON IS AN A2A ADENOSINE RECEPTOR AGONIST THAT IS A CORONARY VASODILATOR. REGADENOSON INJECTION IS A PHARMACOLOGIC STRESS AGENT INDICATED FOR RADIONUCLIDE MYOCARDIAL PERFUSION IMAGING (MPI) IN PATIENTS UNABLE TO UNDERGO ADEQUATE EXERCISE STRESS. REGADENOSON IS A LOW AFFINITY AGONIST (KI ~ 1.3 UM) FOR THE A2A ADENOSINE RECEPTOR, WITH AT LEAST 10-FOLD LOWER AFFINITY FOR THE A1 ADENOSINE RECEPTOR (KI > 16.5 UM), AND WEAK, IF ANY, AFFINITY FOR THE A2B AND A3 ADENOSINE RECEPTORS. ACTIVATION OF THE A2A ADENOSINE RECEPTOR BY REGADENOSON PRODUCES CORONARY VASODILATION AND INCREASES CORONARY BLOOD FLOW