Regadenoson-d3 is the deuterium labeled Regadenoson. Regadenoson (CVT-3146) is a potent and selective A2A adenosine receptor agonist, with Kis of 290 and 1120 nM for rat and pig adenosine A2A receptor, respectively. Regadenoson is selective for the adenosine A2A receptor over adenosine A1 and A2B receptors, and shows 13-fold selectivity over the human adenosine A1 receptor. Regadenoson is a vasodilator stress agent has shifted the landscape of vasodilator myocardial perfusion imaging. Regadenoson increases blood-brain barrier (BBB) permeability in rodents[1][2][3].