Adenosine is a vasodilating agent, which acts on the vascular smooth muscle surface and leads to vasodilation and a considerable increased vascular flow.
Note: This article aims to give a rough description of adenosine.
For detailed and exact information please refer to the information and direction for use or package insert from the pharmaceutical company.
It is commonly used for diagnostic purposes in cardiac stress testing and will accentuate the difference between the normal coronary arteries, which dilate under adenosine administration, and coronary stenoses, which remain fixed and cannot dilate any further 1-3.
It has been also used for diagnostic purposes and treatment in supraventricular tachycardia 3.
Adenosine binds non-selectively to A1, A2A, A2B and A3 receptors of which activation of A2A receptors lead to coronary vasodilation, which is required for the cardiac stress test 1,3.
Activation of A1, A2B and A3 receptors can lead to bronchospasm and atrioventricular block 1.
Adenosine has a half-life of 10-30 seconds.
The usual dosage used on cardiac stress test is the following 1,2:
- infusion of 140 µg/kg for 2-4 min
if there is no increase in heart rate by 10 bpm or drop in blood pressure by ≥ 10 mmHg after 2-3 min of infusion an increase to 210 µg/kg might be considered subject to local and institutional norms 2.
Contraindications of adenosine include 1,2:
- 2nd or 3rd-degree atrioventricular block
- sinus bradycardia (< 40-45 bpm)
- systolic blood pressure ≤ 90 mmHg
- severe arterial hypertension ( e.g. ≥220/120 mmHg)
- acute myocardial infarction
- known hypersensitivity to adenosine
- active bronchoconstriction, asthma or bronchospastic disease requiring regular inhaler use
- severe aortic stenosis or carotid stenosis
- cardiac shunt
- xanthines as aminophylline, theophylline, caffeine act as competitive antagonists
- dipyridamole potentiates its action
intravenous aminophylline: suggested dose 125 mg in 50 mL normal saline by IV infusion for 5–6 min
- 1. Jo Y, Kim J, Park CH, Lee JW, Hur JH, Yang DH, Lee BY, Im DJ, Hong SJ, Kim EY, Park EA, Kim PK, Yong HS. Guideline for Cardiovascular Magnetic Resonance Imaging from the Korean Society of Cardiovascular Imaging-Part 1: Standardized Protocol. (2019) Korean journal of radiology. 20 (9): 1313-1333. doi:10.3348/kjr.2019.0398 - Pubmed
- 2. Kramer CM, Barkhausen J, Bucciarelli-Ducci C, Flamm SD, Kim RJ, Nagel E. Standardized cardiovascular magnetic resonance imaging (CMR) protocols: 2020 update. (2020) Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance. 22 (1): 17. doi:10.1186/s12968-020-00607-1 - Pubmed
- 3. Eltzschig HK. Adenosine: an old drug newly discovered. (2009) Anesthesiology. 111 (4): 904-15. doi:10.1097/ALN.0b013e3181b060f2 - Pubmed