Adenosine dosing.

Adult SVT algorithm

• First dose: 6 mg rapid IV push + 20 mL NS flush.
• Second dose: 12 mg rapid IV push + 20 mL flush (after 1–2 min).
• Third dose: 12 mg rapid IV push + 20 mL flush (may repeat once).
• Warn the patient: brief chest pressure, flushing, "sense of doom" — normal.

Push-and-flush technique

1. Use the largest, most proximal IV you have (AC preferred).
2. Two-syringe or stopcock setup: adenosine and 20 mL flush both loaded.
3. Push the drug as fast as possible.
4. Immediately follow with the flush — no pause.
5. Continuous ECG — expect a brief pause / asystole, then normal rhythm.

Pediatric

• First: 0.1 mg/kg IV/IO (max 6 mg).
• Second: 0.2 mg/kg IV/IO (max 12 mg).

Contraindications & cautions

• 2nd or 3rd degree AV block (without pacemaker).
• Wide-complex tachycardia of unclear origin.
• WPW with atrial fibrillation (can accelerate ventricular response).
• Severe asthma / bronchospasm.
• Effects potentiated by dipyridamole and carbamazepine; blunted by caffeine and theophylline.

Frequently asked

What is the adult adenosine dose?

6 mg rapid IV push, followed by a 20 mL saline flush. If no conversion in 1–2 minutes, give 12 mg. A third dose of 12 mg may be repeated once.

Why do you push adenosine so fast?

Half-life is under 10 seconds. Slow administration lets it degrade before reaching the AV node — it simply won't work.

What is the pediatric dose?

First dose 0.1 mg/kg (max 6 mg). Second dose 0.2 mg/kg (max 12 mg).

When should adenosine be avoided?

Wide-complex tachycardia of unclear origin, WPW with AF, poison/drug-induced tachycardia, and 2nd/3rd degree AV block without pacemaker. Use with caution in asthma (can cause bronchospasm).