How to start an Adenosine (ADR) infusion?

How to Start Adenosine Infusion

For pharmacologic stress testing, administer adenosine as a continuous peripheral intravenous infusion at 0.14 mg/kg/min over 6 minutes (total dose 0.84 mg/kg), with thallium-201 injected at the 3-minute midpoint. 1

Pre-Infusion Requirements

Before starting adenosine infusion, ensure the following critical safety measures are in place:

• Establish adequate IV access through a large peripheral vein (preferably central venous access to prevent fluctuations in coronary blood flow) 2, 1
• Have resuscitative equipment and personnel immediately available, including a defibrillator 2
• Establish continuous ECG monitoring throughout the entire procedure 2
• Verify the patient has avoided methylxanthines (caffeine, theophylline, aminophylline) as these competitively antagonize adenosine's effects 2, 3
• Visually inspect adenosine for particulate matter or discoloration prior to administration; do not use if present 1

Dosing Protocol

The standard infusion protocol follows this specific sequence:

• Calculate infusion rate using the formula: 0.14 (mg/kg/min) × total body weight (kg) ÷ adenosine concentration (3 mg/mL) = infusion rate (mL/min) 1
• Infuse continuously for 6 minutes at the calculated rate 1
• Inject thallium-201 at the 3-minute midpoint of the adenosine infusion 1
• Inject thallium-201 as close to the venous access as possible to prevent inadvertent increase in adenosine dose from IV tubing contents 1

Dose Adjustment Protocol

If the patient shows no signs of adenosine effect (flushing, heart rate changes, or increased coronary flow velocity):

• Increase adenosine dosage by 20 mcg/kg/min up to a maximum of 220 mcg/kg/min 2

Absolute Contraindications

Do not initiate adenosine infusion in patients with:

• Bronchoconstrictive or bronchospastic lung disease (including asthma) due to risk of severe bronchospasm 1, 2
• Second- or third-degree AV block or sick sinus syndrome unless a functioning pacemaker is present 1, 2
• Known hypersensitivity to adenosine 1

Critical Monitoring During Infusion

Throughout the infusion, actively monitor for:

• Continuous ECG changes for development of AV block or arrhythmias 2
• Respiratory status for dyspnea or bronchospasm 1
• Blood pressure for significant hypotension 1
• Patient symptoms including chest discomfort, flushing, shortness of breath, headache, throat/neck/jaw discomfort 1, 3

Important Clinical Pitfalls

Avoid Valsalva maneuvers during infusion as this interrupts continuous drug delivery and causes fluctuations in coronary blood flow 2, 4

Do not use alternative infusion protocols as there are no data on the safety or efficacy of protocols other than the standard 0.14 mg/kg/min over 6 minutes 1

The intracoronary route has not been established for safety or efficacy 1

Management of Adverse Effects

Most adverse effects are transient due to adenosine's ultra-short half-life (<10 seconds):

• Common side effects (flushing, chest discomfort, shortness of breath, headache) typically resolve within 1-2 minutes of discontinuing the infusion 5, 3
• Discontinue adenosine immediately if patient develops severe respiratory difficulties, persistent high-grade AV block, or persistent symptomatic hypotension 1
• Aminophylline and/or nitroglycerin may occasionally be required for symptom management 5
• Do not use methylxanthines (caffeine, aminophylline, theophylline) in patients who experience seizures associated with adenosine 1

Drug Interactions Affecting Dosing

Reduce initial dose to 3 mg (for bolus administration) or proportionally reduce infusion rate in patients:

• Taking dipyridamole or carbamazepine (potentiate adenosine's effects) 3, 4
• With transplanted hearts 3
• When given by central venous access 3

Larger doses may be required in patients taking theophylline, caffeine, or theobromine due to competitive antagonism 3