Introduction
Adenosine is most commonly used to terminate supraventricular tachycardias. The effects of adenosine are enhanced by dipyridamole (antiplatelet agent) and blocked by theophyllines. It should be avoided in asthmatics due to possible bronchospasm.
Mechanism of action
Mechanism of action
- Causes transient heart block in the AV node
- Agonist of the A1 receptor in the atrioventricular node, which inhibits adenylyl cyclase thus reducing cAMP and causing hyperpolarization by increasing outward potassium flux
- Adenosine has a very short half-life of about 8-10 seconds
Adverse effects
- Chest pain
- Bronchospasm
- Transient flushing
- Can enhance conduction down accessory pathways, resulting in increased ventricular rate (e.g. WPW syndrome)
Monitoring
Adenosine should ideally be infused via a large-calibre cannula due to it's short half-life,