Should I hold beta (beta blockers) blockers prior to a Lexiscan (regadenoson) stress test?

Beta-Blockers Should Be Withheld Prior to Lexiscan Stress Test

Beta-blockers do not need to be withheld prior to a regadenoson (Lexiscan) stress test, as they do not interfere with the vasodilatory effects of regadenoson.

Rationale for Continuing Beta-Blockers with Lexiscan

Regadenoson (Lexiscan) is a pharmacologic stress agent that works through a different mechanism than exercise stress testing. According to the FDA drug label for regadenoson:

• "In clinical studies, regadenoson was administered to patients taking other cardioactive drugs (i.e., β-blockers, calcium channel blockers, ACE inhibitors, nitrates, cardiac glycosides, and angiotensin receptor blockers) without reported adverse reactions or apparent effects on efficacy" 1

This is a critical distinction from exercise stress testing, where beta-blockers can significantly impact test results.

Different Recommendations for Different Types of Stress Tests

Exercise Stress Tests

For exercise stress tests, guidelines recommend:

• "Whenever possible, β-blockers (and other anti-ischemic drugs) should be withheld for 4 to 5 half-lives (usually about 48 hours) before exercise stress testing for the diagnosis or initial risk stratification of patients suspected of having IHD" 2

• This is because beta-blockers attenuate heart rate and blood pressure responses during exercise, which can limit the diagnostic value of the test

Pharmacologic (Lexiscan) Stress Tests

For pharmacologic stress tests using regadenoson:

• Beta-blockers do not need to be discontinued as they do not interfere with the vasodilatory effects of regadenoson
• The FDA label specifically notes that regadenoson was administered to patients on beta-blockers without affecting efficacy 1

Potential Risks of Beta-Blocker Discontinuation

Abruptly discontinuing beta-blockers can lead to:

• Rebound tachycardia
• Increased blood pressure
• Potential exacerbation of ischemia
• Risk of precipitating acute coronary syndromes in vulnerable patients 3

Clinical Application

For patients scheduled for a Lexiscan stress test:

1. Continue beta-blockers at their regular dose and schedule
2. Document the medications taken before the test for proper interpretation of results
3. No need for dose adjustment or timing changes related to the Lexiscan test

Common Pitfalls to Avoid

• Don't confuse protocols: Many clinicians incorrectly apply exercise stress test protocols (which require holding beta-blockers) to pharmacologic stress tests
• Don't create unnecessary risk: Discontinuing beta-blockers can create unnecessary risk of rebound phenomena in patients with coronary artery disease
• Don't compromise image quality: Beta-blockers may actually improve image quality by reducing motion artifacts from tachycardia

In summary, beta-blockers should be continued at their regular dosing schedule when performing a Lexiscan (regadenoson) stress test, as they do not interfere with the test's diagnostic accuracy and discontinuation may pose unnecessary risks to the patient.