Regadenoson is a short acting molecule that is related to the purine nucleoside adenosine and acts by stimulating adenosine receptors. The half-life is 2-3 minutes compared to 6 second for adenosine. Adenosine receptor activation results in multiple different actions depending on the location.
Regadenoson is not used in clinical medicine, however is used for cardiac stress testing. The advantages of regadenoson for stress testing over adenosine are mainly the use of a bolus instead of a continuous intravenous infusion.
Side-effects are similar to adenosine and include bronchoconstriction in asthmatics, chest pain, dyspnea, flushing and headaches. When a severe bronchoconstrictive reaction occurs, aminophylline (an adenosine receptor antagonist) is used as the antidote to reverse this effect.
Methylxanthines such as caffeine or theophylline are adenosine receptor antagonists and block the actions of regadenoson. They must not be used 12 hours prior to using regadenoson for stress testing or else a false negative study may result.