From the Guidelines
Regadenoson is a selective adenosine A2A receptor agonist primarily used as a pharmacological stress agent in myocardial perfusion imaging studies for patients who cannot exercise adequately. It is administered as a single intravenous bolus of 0.4 mg (5 mL), followed by a saline flush, with the radiotracer injected 10-20 seconds after the regadenoson. The drug works by causing coronary vasodilation, which increases blood flow in normal coronary arteries while diseased vessels show reduced flow, creating perfusion defects that can be detected on imaging.
Key Points
- Regadenoson is preferred over adenosine in many cases because it causes fewer side effects and has a more selective action, as noted in studies such as 1.
- Common side effects include shortness of breath, headache, flushing, chest discomfort, and gastrointestinal symptoms, which are typically mild and short-lived due to the drug's short half-life of approximately 2-3 minutes.
- Regadenoson should be avoided in patients with high-grade AV block without a pacemaker, severe hypotension, acute coronary syndrome, and in those with bronchospastic lung disease due to the risk of bronchospasm, as highlighted in guidelines like 1 and 1.
- Caffeine and other methylxanthines should be avoided for at least 12 hours before the test as they can interfere with the drug's vasodilatory effects.
Clinical Considerations
- The choice between regadenoson and other stress agents like adenosine or dobutamine depends on patient-specific factors, including the ability to exercise, ECG interpretability, and presence of conditions like bronchospasm or significant heart block, as discussed in 1 and 1.
- In patients with left bundle-branch block, pharmacological stress MPI with regadenoson is suggested over exercise stress imaging due to its higher specificity, as mentioned in 1 and 1.
- Local expertise and availability of resources may also influence the choice of stress test, with regadenoson being a favorable option due to its safety profile and efficacy, as supported by studies like 1.
From the FDA Drug Label
Regadenoson injection is a pharmacologic stress agent indicated for radionuclide myocardial perfusion imaging (MPI) in patients unable to undergo adequate exercise stress. The use of Regadenoson (Lexiscan) is for radionuclide myocardial perfusion imaging (MPI) in patients who are unable to undergo adequate exercise stress 2, 2, 2.
- It is a pharmacologic stress agent.
- The main purpose is to help diagnose heart conditions by simulating exercise stress when a patient cannot perform physical exercise.
From the Research
Use of Regadenoson (Lexiscan)
- Regadenoson is a pharmacologic stress agent used in stress myocardial perfusion imaging (MPI) to evaluate for ischemic heart disease 3, 4, 5, 6, 7.
- It is a selective adenosine 2a (A2a) receptor agonist that increases coronary blood flow by 2.5-fold or greater 5.
- Regadenoson is used as an alternative to adenosine, with less serious adverse effects, and is better tolerated and easily administered 6, 7.
- The use of regadenoson has been documented in specific patient populations, including those with chronic diseases, but its use has not been studied in patients of low socioeconomic class 6.
Adverse Effects
- Regadenoson can cause various adverse effects, including bronchospasm, atrioventricular block, or hypotension 5, 7.
- Adverse effects on the central nervous system, such as seizure, are rarely reported but can occur through A2A receptor activation 4, 5.
- Regadenoson can lower the seizure threshold in susceptible individuals, and therefore, more awareness is required in screening patients at risk 4.
Clinical Utilities
- Regadenoson has established safety and efficacy in most patients with chronic diseases 6.
- It is widely used for myocardial perfusion imaging, with non-inferiority to adenosine for detecting reversible myocardial ischemia 3, 6.
- Regadenoson can be used in patients with mild-to-moderate reactive airway disease, unlike adenosine 7.