Recommended Adenosine Dosing for Supraventricular Tachycardia (SVT)
For adult patients with SVT, adenosine should be administered as an initial 6 mg rapid IV bolus, followed by 12 mg if no response within 1-2 minutes, with the option to repeat the 12 mg dose once more if necessary. 1
Standard Adult Dosing Protocol
- Initial dose: 6 mg rapid IV bolus
- If no response in 1-2 minutes: 12 mg rapid IV bolus
- If still no response: May repeat 12 mg dose once more
- Maximum total dose: 30 mg (6 mg + 12 mg + 12 mg)
Administration Technique
- Administer as rapid IV bolus (over 1-2 seconds)
- Inject as proximal or as close to the heart as possible
- Follow immediately with rapid saline flush
- Continuous ECG monitoring during administration is essential
Dose Adjustments for Special Populations
Reduced Initial Dose (3 mg) for:
- Patients taking dipyridamole or carbamazepine
- Heart transplant recipients
- When administered via central venous access 2
Increased Initial Dose for:
- Patients with significant blood levels of theophylline, caffeine, or theobromine 2
Pediatric Dosing:
- Initial dose: 0.05 mg/kg
- Can increase in increments of 0.05 mg/kg every 1-2 minutes
- Maximum dose: 0.25 mg/kg 3
Efficacy and Safety Considerations
Adenosine is highly effective for SVT involving the AV node, with effectiveness rates of 90-95% for atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) 2. Recent evidence suggests that an initial dose of 12 mg may be associated with:
- Less need for re-dosing
- Greater rates of patient improvement
- Lower rates of hospital admission 4
However, the current guidelines still recommend the 6 mg initial dose for standard practice.
Precautions and Contraindications
Use with Caution or Avoid in:
- Patients with asthma or bronchospastic lung disease (contraindicated)
- Patients with pre-excitation syndromes (risk of accelerated conduction through accessory pathway)
- Severe heart block 2
Common Side Effects (Usually Transient):
- Flushing
- Chest pain
- Dyspnea
- Transient AV block
- Potential for bronchospasm (rare)
- Potential to initiate atrial fibrillation 1
Special Considerations
- Adenosine is safe in pregnancy due to its extremely short half-life 2
- In patients with impaired venous return (e.g., right heart failure), higher-than-recommended doses may occasionally be necessary for effective termination of SVT 5
- The safe use of 18-mg bolus doses has been reported in the literature 1
For refractory cases not responding to maximum adenosine doses, alternative treatments such as calcium channel blockers, beta-blockers, or electrical cardioversion should be considered based on the patient's clinical status.