Adenosine Dual Isotope Stress Test For patients who are unable to exercise adequately on the treadmill, the drug adenosine may be given to produce an effect on the heart similar to exercise. During the test, you will be lying on a stretcher and the drug adenosine will be infused through your IV. The adenosine dosage you will be given is based on your body weight. Adenosine is a vasodilator, so you may feel warm or flushed, or experience chest pressure, headache, dizziness, nausea, or shortness of breath. These symptoms are perfectly normal, and they don’t necessarily mean there is a problem with your heart, but make sure to let the nurse know how you feel. The adenosine is infused over 6 minutes, and Cardiolite is injected at 3 minutes. You will be given some time to rest before having your second scan under the nuclear camera. Please do not leave the area until you have been instructed that your test has been completed. What is Adenosine? Adenosine is a naturally-occurring substance that is used as a diagnostic agent in nuclear stress testing. Adenosine acts as a vasodilator and its actions are similar to that of Persantine. It also increases the blood vessel circumference of the coronary arteries (arteries that feed the heart) in order to increase blood flow to the heart. Adenosine has a short half-life (less than 10 seconds). This means, any side effects you may experience will be generally predictable, short-lived, and easily tolerated. Side effects include: chest pressure, dizziness, shortness of breath, flushing, headache, lightheadedness, nausea, or numbness. Adenosine should not be used in patients who have a hypersensitivity to this drug and in patients who have a known or suspected bronchospastic or bronchoconstrictive lung disease (e.g., asthma). If you do develop side effects to Adenosine that do not disappear quickly, your physician will use the antidote Aminophylline to reverse your side effects.