Adenosine vs. Regadenoson in Cardiac Stress Testing

Study Questions:

How do the safety profiles of adenosine and regadenoson compare in patients undergoing cardiac stress testing?


This retrospective, cohort, single-center study evaluated adverse effects data (i.e., arrhythmia, angina, dizziness, dyspnea, flushing, headache, and use of the rescue agent aminophylline) collected from two outpatient clinics over a 1-year period. One outpatient clinic exclusively used adenosine, while another exclusively used regadenoson. Adult participants between 18 and 88 years of age and requiring pharmacologic stress testing were enrolled consecutively, while those who were incarcerated or pregnant were excluded.


The analysis included 489 participants (254 in the adenosine group and 235 in the regadenoson group). Both groups were similar except for mean age (60.9 vs. 63.9 years, p = 0.004), presence of chronic kidney disease (42.5% vs. 26.0%, p < 0.001), and heart failure (19.3% vs. 12.3%, p = 0.041) were greater in the adenosine group. Nearly 80% of those who received regadenoson experienced an adverse effect, compared with only 31.5% in the adenosine group (p < 0.001). This was mostly due to a statistically higher incidence of arrhythmia (30.6% vs. 16.1%), dyspnea (66.0% vs. 17.7%), headache (25.1% vs. 3.1%), and use of rescue agent (19.2% vs. 0.8%) with regadenoson compared with adenosine. Regadenoson was also associated with more adverse effects in participants with a history of asthma or chronic obstructive pulmonary disease, including dyspnea and greater utilization of the rescue agent. Aside from being more tolerable, adenosine was $25,000 less expensive for the test population than regadenoson based on average wholesale pricing.


These data suggest that adenosine is better tolerated and less expensive than regadenoson when used for pharmacologic cardiac stress testing in the outpatient setting.


Although only a single-center study, this study represents the largest “real-world” sample of how tolerable adenosine and regadenoson are when used for cardiac stress testing in the outpatient setting. It is reasonable to assume that much of the difference in tolerability is related to adenosine’s short half-life (30-40 seconds); regadenoson has a triphasic half-life often persisting for 15-30 minutes. These promising data support the need for additional studies to further determine the safety profile and potential cost-effectiveness of adenosine over regadenoson.

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