Regadenoson

Regadenoson is a selective adenosine A3 receptor agonist primarily used in medical imaging, particularly for myocardial perfusion imaging (MPI). Developed by Astellas Pharma, it was approved by the U.S. Food and Drug Administration (FDA) in 2013 for this purpose. Regadenoson is administered intravenously and is designed to induce vasodilation, particularly in coronary arteries, to enhance blood flow to the heart muscle during imaging studies.

The drug works by binding to adenosine A3 receptors, which are predominantly found in the coronary vasculature. This binding triggers a cascade of events leading to coronary vasodilation, making it easier for contrast agents to perfuse through the heart’s blood vessels. This property is particularly useful in MPI, where assessing blood flow to the heart can help identify conditions such as coronary artery disease.

Regadenoson is typically used in conjunction with single-photon emission computed tomography (SPECT) or positron emission tomography (PET) scans to evaluate myocardial perfusion. It is often preferred over other vasodilators, such as adenosine, due to its shorter duration of action, which reduces the risk of adverse effects like flushing, chest pain, and dizziness. The effects of regadenoson usually subside within 2 to 5 minutes after administration.

Common side effects may include headache, flushing, chest discomfort, nausea, and dizziness. Rare but serious reactions can occur, such as hypotension, arrhythmias, or severe allergic responses. Patients with certain conditions, such as severe heart failure, uncontrolled hypertension, or a history of severe allergic reactions, may require careful monitoring or alternative vasodilators.

Regadenoson is not used for other indications outside of MPI and should not be confused with other adenosine-based medications, which have different mechanisms and applications. It is typically administered by healthcare professionals in a clinical setting to ensure safety and effectiveness.