What is the appropriate dosing for Adenosine?

From the Guidelines

Adenosine should be administered as a rapid intravenous bolus for the treatment of paroxysmal supraventricular tachycardia (PSVT) with an initial dose of 6 mg given as a rapid IV push over 1-2 seconds, followed immediately by a saline flush, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. The medication should be administered through the largest available vein, preferably an antecubital vein, and the patient's arm should be elevated after injection to facilitate rapid delivery to the central circulation. If the first dose does not terminate the arrhythmia within 1-2 minutes, a second dose of 12 mg should be administered in the same manner, and if necessary, a third and final dose of 12 mg can be given. Adenosine has an extremely short half-life of less than 10 seconds, which necessitates this rapid administration technique. The medication works by temporarily blocking AV nodal conduction, interrupting reentry circuits that maintain PSVT. Common side effects include flushing, chest discomfort, dyspnea, and brief asystole, but these typically resolve within seconds due to the drug's short half-life. Reduced doses (3 mg initially) should be considered for patients taking dipyridamole or carbamazepine, those with heart transplants, or when administering through central venous access, as noted in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. It is also important to note that adenosine is safe and effective in pregnancy, as stated in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. Key points to consider when administering adenosine include:

• Initial dose: 6 mg rapid IV bolus
• Subsequent doses: up to 2 additional doses of 12 mg if necessary
• Administration technique: rapid IV push over 1-2 seconds, followed by saline flush
• Contraindications: asthma, heart block, or other conditions where adenosine may worsen the patient's condition
• Side effects: flushing, chest discomfort, dyspnea, and brief asystole, which are typically transient and resolve within seconds.

From the FDA Drug Label

The recommended adenosine injection dose is 0.14 mg/kg/min infused over six minutes (total dose of 0.84 mg/kg)

Table 1 Dosage Chart for Adenosine Injection The nomogram displayed in Table 1 was derived from the following general formula: 0.14 (mg/kg/min) x total body weight (kg) = Infusion rate (mL/min) Adenosine injection concentration (3 mg/mL)

The recommended dosage of adenosine is 0.14 mg/kg/min infused over six minutes, with a total dose of 0.84 mg/kg 2 2.

• The infusion rate can be calculated using the formula: 0.14 (mg/kg/min) x total body weight (kg) = Infusion rate (mL/min), considering an adenosine injection concentration of 3 mg/mL.
• It is essential to administer adenosine injection only as a continuous peripheral intravenous infusion.

From the Research

Adenosine Dosing for Supraventricular Tachycardia

• The dosing of adenosine for supraventricular tachycardia (SVT) is typically 6 mg as an initial dose, followed by 12 mg if conversion is not achieved 3, 4.
• Adenosine is effective in terminating SVT, but it has a significant side-effect profile, including minor adverse events such as nausea, chest tightness, shortness of breath, and headache 3.
• The use of adenosine versus calcium channel antagonists (CCAs) for SVT has been compared in several studies, with no significant difference in reversion rate or relapse rate between the two drugs 3, 5.
• However, CCAs may be associated with a lower risk of minor adverse events compared to adenosine 3, 4.
• The European Society of Cardiology guidelines recommend the use of vagal manoeuvres and adenosine as first-line therapies in the acute diagnosis and management of SVT, with alternative therapies including beta-blockers and calcium channel blockers 6, 7.

Comparison with Calcium Channel Antagonists

• Calcium channel antagonists, such as verapamil and diltiazem, are also effective in terminating SVT, and may be associated with a lower risk of minor adverse events compared to adenosine 3, 4.
• The use of slow infusion of calcium channel blockers has been shown to be safe and effective in the emergency treatment of stable patients with SVT 4.
• However, the choice of treatment should be individualized based on patient factors, such as the presence of underlying heart disease or other medical conditions 5, 6.

Clinical Guidelines and Recommendations

• The European Society of Cardiology guidelines recommend catheter ablation as a first-line treatment for most patients with SVT, recognizing its effectiveness and safety 7.
• The guidelines also provide recommendations for the use of antiarrhythmic drug treatment, including the use of beta blockers and calcium channel blockers, and emphasize the importance of avoiding antiarrhythmic drugs during the first trimester of pregnancy 7.