[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Antiarrhythmics](https://durgical.com/en/pharmacology/classes/antiarrhythmics/) › Adenosine

# Adenosine

## Antiarrhythmics?

Antiarrhythmics

## High alert?

An error with this medicine can cause serious harm: double checks and protocols are used.

A rapid intravenous push that blocks the AV node for a few seconds and stops most re-entrant supraventricular tachycardias.

Updated Nov 1, 2026

## Quick facts

**Group**
[Antiarrhythmics](https://durgical.com/en/pharmacology/classes/antiarrhythmics/)

**Target**
Adenosine A1 receptor (AV node)

**Used for**
PSVT that uses an accessory pathway

**Key effects**
Facial flushing · Chest pressure or pain

**Monitor**
Continuous ECG recording during the push

**ATC**
C01EB10

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Adenosine A1 receptor (AV node)**Adenosine

ⓘ The figure shows adenosine bound to the human adenosine A1 receptor coupled to its Gi protein; the structure also holds an allosteric modulator at a separate site.

**Target in 3D:** Adenosine A1 receptor (AV node). PDB structure 7LD3 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/7LD3) · Drag to rotate · pinch to zoom

Adenosine stimulates A1 receptors in the AV node and sinus node. Through Gi proteins it opens acetylcholine/adenosine-sensitive potassium channels and lowers cAMP and calcium entry, so the cells hyperpolarise and AV conduction is briefly blocked. Re-entry circuits that use the AV node (AVNRT, AVRT) are broken; atrial fibrillation, flutter and VT are not converted, though the ventricular rate may slow for a moment and unmask flutter waves.

- Adenosine activates A1 receptors in the AV node
- Potassium channels open and the nodal cells hyperpolarise
- AV conduction stops for seconds, breaking the re-entry circuit
- Red cells and endothelium take it up within seconds

## Indications

- Conversion of paroxysmal supraventricular tachycardia to sinus rhythm, after vagal manoeuvres [Supraventricular tachycardia (AVNRT, AVRT) →](https://durgical.com/en/conditions/supraventricular-tachycardia/)
- PSVT that uses an accessory pathway (Wolff-Parkinson-White), when the complex is regular and narrow [Wolff-Parkinson-White syndrome →](https://durgical.com/en/conditions/wolff-parkinson-white-syndrome/)

## Adverse effects

### Common

- Facial flushing
- Chest pressure or pain and breathlessness
- Headache and a sense of doom
- Brief pauses or new rhythms at conversion

### Serious (rare, important)

- Prolonged asystole or high-grade AV block
- Ventricular fibrillation or atrial fibrillation (rare)
- Bronchospasm in asthma

## Contraindications

- Second- or third-degree AV block without a working pacemaker
- Sick sinus syndrome or symptomatic bradycardia without a pacemaker
- Hypersensitivity to adenosine

## Key interactions

**Caffeine and theophylline (methylxanthines)**
Block adenosine receptors: larger doses may be needed or it may fail

**Dipyridamole**
Blocks adenosine uptake and strengthens its effect; smaller doses may be enough

**Carbamazepine**
Can deepen heart block

**Digoxin, with or without verapamil**
Rare reports of ventricular fibrillation

## What is monitored

- Continuous ECG recording during the push
- Blood pressure and heart rate
- Breathing and wheeze in patients with asthma

## Administration and safety

- Given as a rapid intravenous push directly into a peripheral vein, followed at once by a rapid saline flush, because it is cleared in seconds.
- If given through a line, it is injected at the port closest to the patient.
- A defibrillator and resuscitation equipment are at hand.
- Not refrigerated, because crystals can form; the solution must be clear.

## Pregnancy and breastfeeding

Adenosine is a natural body molecule with a very short half-life, so no fetal effects are expected, but human data are lacking and it is used in pregnancy only if clearly needed.

## Nursing care

- Warn the patient that flushing, chest pressure and a brief feeling of doom are expected and pass in seconds.
- Run an ECG strip during the push to document the response and any pause.
- Ask about asthma, caffeine intake, theophylline and dipyridamole beforehand.
- After conversion, watch rhythm and blood pressure for recurrence.

## Pharmacokinetics

**Distribution**
Cleared from blood within seconds by uptake into red cells and vascular endothelium

**Metabolism**
Phosphorylated to AMP or deaminated to inosine inside cells

**Half-life**
Less than ten seconds

**Onset and duration**
Seconds after a rapid push; adverse effects are brief

## Memory aid

Adenosine is a ten-second reset button: push fast, flush fast, expect a flat line for a moment.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is adenosine followed immediately by a rapid saline flush?

Its half-life is under ten seconds; the flush pushes it to the heart before red cells and endothelium take it up.

## Which rhythms does adenosine convert and which does it not?

It converts re-entrant SVT that uses the AV node (AVNRT, AVRT); it does not convert atrial fibrillation, flutter or ventricular tachycardia.

## How do theophylline and dipyridamole change the response to adenosine?

Theophylline (and caffeine) block its receptors and weaken it; dipyridamole blocks its uptake and strengthens it.

## Which receptor in the AV node mediates adenosine's effect?

The A1 adenosine receptor, coupled to Gi, which opens potassium channels.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/adenosine/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**High alert**
An error with this medicine can cause serious harm: double checks and protocols are used.

## Connections

## Related drugs 4

- [Verapamil](https://durgical.com/en/pharmacology/verapamil/)
- [Diltiazem](https://durgical.com/en/pharmacology/diltiazem/)
- [Dipyridamole](https://durgical.com/en/pharmacology/dipyridamole/)
- [Digoxin](https://durgical.com/en/pharmacology/digoxin/)

## Related conditions 2

- [Supraventricular tachycardia (AVNRT, AVRT)](https://durgical.com/en/conditions/supraventricular-tachycardia/)
- [Wolff-Parkinson-White syndrome](https://durgical.com/en/conditions/wolff-parkinson-white-syndrome/)

[← Back to the class: Antiarrhythmics](https://durgical.com/en/pharmacology/classes/antiarrhythmics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - ADENOSINE injection](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=546642f2-662f-46cf-9d82-5bb3bdcc7677) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C01EB10) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [7LD3: Cryo-EM structure of the human adenosine A1 receptor-Gi2-protein complex bound to its endogenous agonist and an allosteric ligand](https://www.rcsb.org/structure/7LD3) (RCSB Protein Data Bank, 2021).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/adenosine/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/adenosine/