What is the proper administration protocol for adenosine (adenosine)

Proper Administration Protocol for Adenosine

Adenosine should be administered as a 6 mg rapid IV bolus through a large proximal vein (e.g., antecubital), followed immediately by a 20 mL saline flush. If no response occurs within 1-2 minutes, administer a 12 mg rapid IV bolus followed by another saline flush, which may be repeated once more if necessary. 1, 2

Dosing Protocol

• Initial dose: 6 mg IV as a rapid bolus over 1-2 seconds 1, 2
• If no response within 1-2 minutes: 12 mg IV as a rapid bolus 1, 2
• If still no response after another 1-2 minutes: May repeat the 12 mg dose once more 1, 2
• Maximum total dose: 24 mg (6 mg + 12 mg + 12 mg) 2

Administration Technique

• Use the most proximal IV site possible (antecubital preferred) 1
• Administer as a rapid IV push over 1-2 seconds 1, 2
• Follow immediately with a rapid 20 mL saline flush to ensure the medication reaches the central circulation quickly 1, 2
• A two-syringe technique is preferred (one for adenosine, one for flush) 1
• Continuous ECG monitoring should be employed during administration 1

Indications and Mechanism

• Primary indication: Termination of paroxysmal supraventricular tachycardia (PSVT) 1, 3
• Adenosine blocks AV nodal conduction, disrupting reentry circuits that involve the AV node 3, 4
• Extremely short half-life (<10 seconds) allows for rapid dose escalation if needed 3, 4

Special Considerations

• Reduce initial dose to 3 mg in patients taking dipyridamole or carbamazepine, those with transplanted hearts, or if given by central venous access 1
• Higher doses may be required for patients with significant blood levels of theophylline, caffeine, or theobromine 1
• A defibrillator must be immediately available during administration, especially when WPW is suspected 1
• Recent evidence suggests that an initial dose of 12 mg may be associated with higher rates of conversion and less need for additional doses 5

Contraindications

• Second or third-degree AV block (unless patient has a functioning pacemaker) 6
• Sick sinus syndrome or symptomatic bradycardia (unless patient has a functioning pacemaker) 6
• Known or suspected bronchoconstrictive lung disease (e.g., asthma) 1, 6
• Known hypersensitivity to adenosine 6
• Heart transplant recipients (contraindicated unless specifically directed by transplant specialists) 1, 7

Potential Adverse Effects

• Common side effects include flushing, dyspnea, chest discomfort, and transient AV block 2, 3
• Most side effects are transient and resolve within 60 seconds due to adenosine's short half-life 2, 3
• Rare but important adverse effects include bronchospasm, complete heart block, and initiation of atrial fibrillation 2

Clinical Pearls

• Adenosine is preferred over calcium channel blockers for PSVT due to its rapid onset, short duration, and better safety profile 1, 3
• Continuous ECG recording during administration helps distinguish drug failure from successful termination with immediate arrhythmia recurrence 1
• If adenosine fails, consider longer-acting AV nodal blocking agents (calcium channel blockers or beta-blockers) for stable patients or synchronized cardioversion for unstable patients 1
• Adenosine may be used diagnostically to unmask atrial flutter or atrial tachycardia, though it rarely terminates these arrhythmias 1, 4