adenosine + regadenoson

Adenosine + regadenoson is a combination of two pharmacologic stress agents used primarily in myocardial perfusion imaging (MPI) for the diagnosis of coronary artery disease in patients unable to undergo adequate exercise stress. Adenosine is a naturally occurring, non-selective agonist of all subtypes of adenosine receptors (A1, A2A, A2B, and A3), leading to coronary vasodilation and increased myocardial blood flow. Regadenoson is a selective low-affinity agonist for the A2A adenosine receptor that also induces coronary vasodilation but with greater selectivity and fewer side effects compared to adenosine. Both drugs act by increasing coronary blood flow through activation of the A2A receptor but differ in their selectivity profiles and administration protocols. Adenosine requires continuous infusion due to its short half-life, while regadenoson can be administered as a single bolus dose[1][5][6][7][8].