Adenosine is an agonist at A1-adenosine receptors and opens ACh-sensitive potassium channels, leading to hyperpolarisation and inhibition of calcium channels. This causes a reduction in nodal conduction and a very brief period of heart block sufficient to cause termination of the SVT.
Intravenous bolus administration with increasing dosages is used until the arrhythmia is terminated, alternative diagnosis made or maximum dose reached.
Adenosine has an exceptionally short half life so adverse effects are very short lived. These include:
- Bronchospasm
- Chest pain
- Flushing
- Nausea
Bradyarrhythmia may occur.
Patients should be warned that the sensation associated with adenosine is unpleasant but short lived. Many describe it like being "thumped in the chest".
Adenosine has a half-life of 8-10 seconds, making any effects short lived.
