Editing Adenosine (section)

== Medical uses ==
=== Supraventricular tachycardia ===
In individuals with [[supraventricular tachycardia]] (SVT), adenosine is a first line treatment used to help identify and convert the rhythm.<ref name="pmid39033975">{{cite journal |vauthors=Ciriello GD, Sorice D, Orlando A, Papaccioli G, Colonna D, Correra A, Romeo E, Esposito R, De Marco M, Diana V, Giordano M, Barrile LS, Russo MG, Sarubbi B |title=Antiarrhythmic therapy for narrow QRS supraventricular tachyarrhythmias in newborns and infants in the first year of life: Potent tools to be handled with care |journal=Indian Pacing and Electrophysiology Journal |volume=24 |issue=5 |pages=271–281 |date=2024 |pmid=39033975 |pmc=11480843 |doi=10.1016/j.ipej.2024.07.005}}</ref><ref>{{Cite journal | vauthors = Borea PA, Gessi S, Merighi S, Vincenzi F, Varani K | title = Pharmacology of Adenosine Receptors: The State of the Art | journal = Physiological Reviews | volume = 98 | issue = 3 | pages = 1591–1625 | date = July 2018 | pmid = 29848236 | doi = 10.1152/physrev.00049.2017 | s2cid = 44107679 | doi-access = free | hdl = 11392/2391482 | hdl-access = free }}</ref><ref>{{Cite journal | vauthors = Delacrétaz E | title = Clinical practice. Supraventricular tachycardia | journal = The New England Journal of Medicine | volume = 354 | issue = 10 | pages = 1039–1051 | date = March 2006 | pmid = 16525141 | doi = 10.1056/NEJMcp051145 }}</ref><ref>{{Cite journal | vauthors = Belhassen B, Pelleg A | title = Electrophysiologic effects of adenosine triphosphate and adenosine on the mammalian heart: clinical and experimental aspects | journal = Journal of the American College of Cardiology | volume = 4 | issue = 2 | pages = 414–424 | date = August 1984 | pmid = 6376597 | doi = 10.1016/S0735-1097(84)80233-8 | s2cid = 21575090 | doi-access = free }}</ref>

Certain SVTs can be successfully terminated with adenosine.<ref name="pmid19000353">{{Cite journal | vauthors = Mitchell J, Lazarenko G | title = Wide QRS complex tachycardia. Diagnosis: Supraventricular tachycardia with aberrant conduction; intravenous (IV) adenosine | journal = CJEM  | volume = 10 | issue = 6 | pages = 572–3, 581 | date = November 2008 | pmid = 19000353 }}</ref> This includes any [[re-entrant arrhythmia]]s that require the AV node for the re-entry, e.g., [[AV reentrant tachycardia]] (AVRT) and [[AV nodal reentrant tachycardia]] (AVNRT). In addition, [[atrial tachycardia]] can sometimes be terminated with adenosine.<ref name="Goyal 2022">{{Cite book | vauthors = Goyal A, Basit H, Bhyan P, Zeltser R | chapter = Reentry Arrhythmia |date=2022| chapter-url= http://www.ncbi.nlm.nih.gov/books/NBK537089/|title = StatPearls|place=Treasure Island, FL |publisher=StatPearls Publishing|pmid=30725774|access-date=2022-01-28}}</ref>

Fast rhythms of the heart that are confined to the [[atrium (anatomy)|atria]] (e.g., [[atrial fibrillation]] and [[atrial flutter]]) or [[ventricle (heart)|ventricles]] (e.g., [[monomorphic ventricular tachycardia]]), and do not involve the AV node as part of the re-entrant circuit, are not typically converted by adenosine. However, the ventricular response rate is temporarily slowed with adenosine in such cases.<ref name="Goyal 2022" />

Because of the effects of adenosine on AV node-dependent SVTs, adenosine is considered a class V [[antiarrhythmic agents|antiarrhythmic agent]]. When adenosine is used to [[cardioversion|cardiovert]] an abnormal rhythm, it is normal for the heart to enter ventricular [[asystole]] for a few seconds. This can be disconcerting to a normally conscious patient, and is associated with angina-like sensations in the chest.<ref>{{Cite book|title=Coronary Pressure| vauthors = Pijls NH, De Bruyne B |year=2000|publisher=Springer|isbn=0-7923-6170-9 }}{{page needed|date=August 2019}}</ref>

=== Nuclear stress test ===
Adenosine is used as an adjunct to [[thallium]] (TI 201) or [[Technetium-99m|technetium (Tc99m)]] [[myocardial perfusion scintigraphy]] (nuclear stress test) in patients unable to undergo adequate stress testing with exercise.<ref>{{Cite journal | vauthors = O'Keefe JH, Bateman TM, Silvestri R, Barnhart C | title = Safety and diagnostic accuracy of adenosine thallium-201 scintigraphy in patients unable to exercise and those with left bundle branch block | journal = American Heart Journal | volume = 124 | issue = 3 | pages = 614–621 | date = September 1992 | pmid = 1514488 | doi = 10.1016/0002-8703(92)90268-z }}</ref>

=== Dosage ===
When used to treat SVT, adenosine is administered [[Intravenous therapy|intravenously]] as a rapid [[Bolus (medicine)|bolus]] (typically 0.10–0.15 mg/kg initially) over 1-2 seconds, followed by a rapid [[saline flush]] (often using a 2-way or 3-way stopcock). If the initial dose is ineffective, it may be repeated every 2 minutes with a slightly increased dose (0.05–0.1 mg/kg increments) every 2 minutes up to a maximum total dose of 0.3 mg/kg (not exceeding 12 mg). Due to adenosine's extremely short half-life (less than 10 seconds), it is often injected through a [[central venous line]] or a large proximal peripheral vein; administration into lower extremities, [[PICC line]]s, or smaller veins may lead to therapeutic failure due to rapid metabolism before reaching the heart.<ref name="pmid39033975"/> When given to dilate the arteries, such as in a "stress test", the dosage is typically 0.14&nbsp;mg/kg/min, administered for 4 or 6 minutes, depending on the protocol.

The recommended dose may be increased in patients on theophylline since methylxanthines prevent binding of adenosine at receptor sites. The dose is often decreased in patients on [[dipyridamole]] (Persantine) and [[diazepam]] (Valium) because adenosine potentiates the effects of these drugs. The recommended dose is also reduced by half in patients presenting [[congestive heart failure]], [[myocardial infarction]], [[shock (circulatory)|shock]], [[hypoxia (medical)|hypoxia]], and/or chronic liver disease or [[chronic kidney disease]], and in [[elderly]] patients.