Antiarrhythmic (Adenosine Receptor Agonist) Pregnancy: Use with caution — short half-life limits fetal exposure; used for SVT in pregnancy when other measures fail

Adenosine (IV — SVT Termination)

Brand names: Adenocor

Adult dose

Dose: 6 mg rapid IV bolus; if no response after 1–2 min: 12 mg; repeat 12 mg once more if needed

Route: IV (rapid bolus into large antecubital or central vein)

Frequency: Sequential boluses as above

Max: 30 mg total

Half-life 10–30 seconds — must be given as rapid bolus followed immediately by saline flush to reach heart before metabolism. Causes transient AV block — terminates re-entrant SVT. Diagnostic use: unmasks atrial flutter P-waves during AV block.

Paediatric dose

Dose: 0.1 mg/kg

Route: IV rapid bolus

Frequency: Increasing doses

Max: 0.5 mg/kg (max 12 mg)

SVT in children: 0.1 mg/kg rapid IV bolus; if no response: 0.2 mg/kg, then 0.3 mg/kg. Max single dose 12 mg.

Dose adjustments

Renal

No dose adjustment required — not renally cleared.

Hepatic

No dose adjustment required.

Paediatric weight-based calculator

Patient weight (kg)

SVT in children: 0.1 mg/kg rapid IV bolus; if no response: 0.2 mg/kg, then 0.3 mg/kg. Max single dose 12 mg.

Clinical pearls

Always warn conscious patients: 'You will feel a very unpleasant sensation for a few seconds — this is normal and will pass'
WPW with AF: adenosine is CONTRAINDICATED — slowing AV node preferentially routes conduction via accessory pathway causing rapid ventricular response or VF
Ultra-short half-life (10–30 sec) means side effects are brief — reassure patient before administering

Contraindications

2nd or 3rd degree AV block (without pacemaker)
Sick sinus syndrome
Long QT syndrome
Severe asthma/COPD (causes bronchospasm)
Wolff-Parkinson-White syndrome with AF (can accelerate conduction via accessory pathway — risk of VF)

Side effects

Transient chest tightness/pain (almost universal — warn patient)
Flushing
Dyspnoea
Transient complete heart block/asystole (seconds — intentional effect)
Bronchospasm (contraindicated in asthma)
Facial flushing

Interactions

Dipyridamole (blocks adenosine metabolism — use 1/4 dose of adenosine)
Theophylline/caffeine (adenosine receptor antagonists — may block effect; higher doses needed)
Carbamazepine (additive AV block)

Monitoring

Continuous ECG with rhythm strip during administration
BP
SpO2
Clinical response (SVT termination vs. P-wave revelation)

Reference: BNFc; BNF 90; BNFc; Resuscitation Council UK ALS 2021; ESC Arrhythmia Guidelines 2019. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways