Adenosine

Question 1

What is adenosine used for?

Answer 1

Adenosine is most commonly used to terminate supraventricular tachycardias.

Question 2

Effects of adenosine enhanced by? Blocked by?

Answer 2

The effects of adenosine are enhanced by dipyridamole (antiplatelet agent) and blocked by theophyllines.

Question 3

Contraindications adenosine?

Answer 3

It should be avoided in asthmatics due to possible bronchospasm.

Question 4

Mechanism of action of adenosine?

Answer 4

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

Question 5

Adenosine administration?

Answer 5

Adenosine should ideally be infused via a large-calibre cannula due to it’s short half-life

Question 6

Adverse effects adenosine?

Answer 6

chest pain
bronchospasm
transient flushing
can enhance conduction down accessory pathways, resulting in increased ventricular rate (e.g. WPW syndrome)