Adenosine: Definition, Uses & Side Effects

Instructor: Justine Fritzel

Justine has been a Registered Nurse for 10 years and has a Bachelor's of Science in Nursing degree.

In this lesson, we will learn about a medication called adenosine and what it is used for. We will also learn about the side effects of adenosine to be aware of.

Heart Health

Brady is a 65 year old man that looks older than his age. He has worked physically hard all of his life, working 60+ hours every week. He has smoked cigarettes since he was a teenager and rarely sees a doctor. He broke his ankle a couple months ago, and since that time, he has gained 30 pounds and now he can hardly do anything. When he tries to push himself physically, he has been experiencing chest pain. As long as he sits down and rests, it goes away, so he hasn't told anyone about it. One day his wife noticed he wasn't feeling well and she convinced him to make an appointment with a doctor.

Brady sees his doctor who expresses concern about his heart health. He tells him that he wants him to do a stress test to see how his heart functions under pressure. He explains to him that this is a treadmill test. Brady tells the doctor that there is no way that he can walk on the treadmill between his ankle pain and activity intolerance since his weight gain. His doctor explains to him that there is another way to do this test that doesn't require physical exercise.

Uses of Adenosine

Adenosine is a medication that is given through an IV so it goes directly into your bloodstream. It is classified as an antiarrhythmic drug and has different uses. Arrhythmia means an abnormal heart rate, so the classification of this drug indicates it is to correct abnormal heart rates.


The stress test that Brady's doctor explained uses adenosine instead of exercising on the treadmill. The adenosine works by dilating or enlarging the coronary arteries that feed blood to the heart muscle. When these arteries are dilated, it increases blood flow to the heart. Think of it like a straw. If you are trying to drink out of a really skinny straw, you only get very little fluid to your mouth. But if you use a big, wide straw, you can get more fluid to your mouth. When you are given adenosine, it makes your coronary arteries like the big, wide straw carrying more blood to your heart. This simulates what happens when you exercise to help them evaluate the functioning of your heart.

Adenosine is also used in emergency situations. Your heart may go into a very fast rhythm. If the heart is beating abnormally fast, it doesn't allow enough time to fill with blood to pump out to the body. Emergency responders will use an automated external defibrillator (AED) or electrocardiogram (ECG) to detect the abnormal heart rhythm. In these situations, adenosine works to slow the conduction of the heart and help return it back to a normal, effective rhythm.

Side Effects of Adenosine

As with any medication, you need to be aware of side effects. Since adenosine is an injectable medication, you will be under medical care when receiving it. It is important to report any side effects to your healthcare provider.

Signs of an allergic reaction include difficulty breathing, itching, swelling or hives. This is a serious reaction and needs to be reported immediately. Other serious side effects that can occur, although are not common, include cardiac arrest, other arrhythmias, a very slow heart rate, or low blood pressure.

More common side effects that may not necessarily be as serious include feeling lightheaded, flushed, or having a headache.

Lesson Summary

Adenosine is classified as an antiarrhythmic drug that is available by prescription only. It is an injectable medication that is given directly into your vein. Arrhythmia means an abnormal heart rate so the class indicates it is to correct the heart rhythm.

A typical test to help diagnose coronary heart disease is a stress test of walking on a treadmill to evaluate the function of the heart. Some people are not physically able to do this test so an alternative is to use adenosine. Adenosine dilates the coronary arteries, which increases blood flow. This simulates what happens during exercise so the doctors can still evaluate the function of the heart even if a person is unable to do a stress test.

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