RegadenosonEdit
Regadenoson is a pharmacologic agent used to induce vasodilation of the coronary arteries during stress testing for heart imaging. Sold under the brand name Lexiscan, it is a selective A2A adenosine receptor agonist that enables rapid, single-bolus administration to facilitate myocardial perfusion imaging. By activating the A2A receptor on vascular smooth muscle, regadenoson increases blood flow to the heart, helping clinicians identify regions with reduced perfusion during imaging. In outpatient cardiology labs and nuclear medicine suites, regadenoson has become a convenient alternative to longer, continuous-infusion vasodilators, aligning with policy aims to improve efficiency and patient throughput while preserving safety under physician supervision. myocardial perfusion imaging pharmacologic stress test SPECT
Regadenoson is used in the context of pharmacologic stress testing for myocardial perfusion imaging, most commonly in conjunction with single-photon emission computed tomography (SPECT) or, less frequently, positron emission tomography (PET). Because many patients cannot perform traditional exercise stress testing, regadenoson offers a way to elicit coronary vasodilation without requiring physical exertion. This has implications for access to diagnostic testing across diverse patient populations and care settings, and analysts often weigh its use against alternative vasodilators to balance diagnostic quality, safety, and workflow efficiency. pharmacologic stress test myocardial perfusion imaging SPECT PET
Mechanism of action
Regadenoson acts as a selective agonist of the A2A adenosine receptor, which is abundant on coronary vasculature. Activation of this receptor leads to preferential dilation of coronary arteries, increasing myocardial blood flow. The result is a more uniform distribution of radiotracer in well-perfused tissue and relatively accentuated imaging of regions with compromised perfusion. The receptor-selective action helps to limit some of the broader hemodynamic effects associated with nonselective vasodilators. For background mechanisms, see A2A adenosine receptor and vasodilation.
Administration and pharmacokinetics
Regadenoson is given as a single IV bolus, typically 0.4 mg, followed closely by the radiotracer used for imaging. The vasodilatory effect begins rapidly, often within seconds, and lasts only a few minutes, which simplifies scheduling compared with longer infusion protocols. Radiotracer administration usually occurs within about a minute after the bolus, and imaging is performed after tracer uptake stabilizes. Because regadenoson can interact with other drugs that affect adenosine signaling, clinicians consider patient medications and recent stimulant intake when planning the test. Substances such as caffeine or theophylline can attenuate the vasodilatory response, so avoidance prior to testing is often advised. Technetium-99m caffeine theophylline
Indications and clinical use
Regadenoson is indicated for patients undergoing pharmacologic stress testing to evaluate myocardial perfusion and to identify ischemic regions of the heart. It is particularly useful for patients who have limited ability to exercise or who would otherwise face safety or tolerance concerns with exercise-based testing. In practice, regadenoson is part of a broader strategy to provide timely, accurate diagnostics in a cost-efficient outpatient setting, with decisions guided by contemporary clinical guidelines and payer policies. myocardial perfusion imaging pharmacologic stress test American College of Cardiology American Heart Association
Safety, contraindications, and adverse effects
Common adverse effects include headache, flushing, chest discomfort, and shortness of breath, along with mild hypotension and nausea in some patients. More serious but less frequent events can include arrhythmias or significant conduction disturbances, particularly in patients with underlying heart rhythm disorders. The safety profile is generally favorable when screening criteria are carefully applied and when patients are monitored during testing. Regadenoson is contraindicated in patients with certain conduction abnormalities (e.g., high-grade heart block without a pacemaker) or in those with known hypersensitivity to the drug, and it should be used with caution in individuals with significant reactive airway disease due to the risk of bronchospasm. Given the drug’s pharmacology, clinicians also consider interactions with other adenosine-signaling agents and stimulants to avoid blunted efficacy or heightened adverse effects. bronchospasm A2A adenosine receptor FDA theophylline caffeine
Regulatory status and branding
Regadenoson received regulatory approval for use in pharmacologic stress testing in the United States, with the brand Lexiscan serving as the familiar reference in clinical practice. Regulatory oversight by agencies such as the FDA governs indications, labeling, and post-market safety monitoring, while physicians determine when regadenoson is the appropriate choice within a given diagnostic pathway. Continued evaluation of comparative effectiveness and safety informs updates to practice guidelines and insurer coverage decisions. FDA Lexiscan
Economic and policy considerations
From a policy-oriented perspective, regadenoson represents a diagnostic option that can streamline workflow in busy nuclear cardiology labs, reducing procedure time and enabling outpatient testing. Advocates emphasize the potential for improved patient throughput, shorter turnover between cases, and the ability to serve a broader patient population, particularly those who cannot perform stress testing by exercise. Payers and policymakers weigh these workflow efficiencies against drug costs, the price of imaging studies, and the overall cost-effectiveness of alternative stress agents such as adenosine and dipyridamole. In regions with constrained access to advanced imaging or narrow hospital budgets, regadenoson-based protocols may be favored for their operational simplicity. cost-effectiveness healthcare policy Adenosine Dipyridamole nuclear medicine
Controversies and debates
Debates surrounding regadenoson often center on balancing diagnostic accuracy, patient experience, and cost. Proponents highlight its rapid, single-bolus administration and generally better tolerability compared with nonselective vasodilators, arguing these benefits translate into safer, more accessible testing in outpatient settings. Critics point to the drug’s higher price relative to some alternatives and emphasize that adverse effects, though typically mild, require careful patient selection and monitoring. Some clinicians advocate a tailored approach, choosing regadenoson or alternatives based on patient comorbidity, such as reactive airway disease or conduction abnormalities, and on local expertise. These discussions reflect a broader tension in health care between adopting innovative, convenience-enhancing technologies and ensuring sustained cost containment and equitable access. Adenosine Dipyridamole pharmacologic stress test cardiology healthcare policy