Intravenous Adenosine is indicated for: Conversion of paroxysmal supraventricular tachycardia (PSVT) to normal sinus rhythm, including cases associated with accessory pathways such as Wolff-Parkinson-White Syndrome.

This formulation is a sterile, nonpyrogenic solution intended for rapid intravenous bolus administration. Adenosine injection slows conduction through the A-V node, interrupts reentry circuits involving the A-V node, and helps restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia.

Adult:

• Initial dose: 6 mg given as rapid IV bolus (administered over 1-2 second period).
• Repeat administration: If the first dose does not result in elimination of the supraventricular tachycardia within 1-2 minutes, 12 mg should be given as rapid intravenous bolus. This 12 mg dose may be repeated for second time if required.

Pediatric: The dosages used in neonates, infants, children and adolescents were equivalent to those administered to adults on a weight basis.

• Body weight < 50 kg: Initial dose - 0.05 to 0.1 mg/kg as a rapid IV bolus given either centrally or peripherally. A saline flush should follow.
• Body weight > 50 kg: The adult dose is recommended. Doses greater than 12 mg are not recommended for adult and pediatric patients.

Repeat administration: If conversion of PSVT does not occur within 1-2 minutes, additional bolus injections of adenosine can be administered at incrementally higher doses, increasing the amount given by 0.05 to 0.1 mg/kg. A saline flush should follow. This process should continue until sinus rhythm is established or a maximum single dose of 0.3 mg/kg is used.

Intravenous Adenosine has been effectively used alongside other cardioactive agents such as Quinidine, beta-adrenergic blockers, calcium channel blockers, and angiotensin-converting enzyme (ACE) inhibitors without significant changes in adverse effect profiles. However, Digoxin and Verapamil, when used with Adenosine, have rarely been associated with ventricular fibrillation. Due to possible additive or synergistic depressant effects on the SA and AV nodes, Adenosine should be administered with caution in patients receiving these agents. In patients taking Digitalis, the use of Adenosine has rarely been linked to ventricular fibrillation. The pharmacologic effects of Adenosine are antagonized by methylxanthines such as caffeine and theophylline.

Intravenous Adenosine is contraindicated in:

• Second- or third-degree AV block (except in patients with a functioning artificial pacemaker).
• Sinus node disorders, including sick sinus syndrome or symptomatic bradycardia (unless a functioning artificial pacemaker is present).
• Known hypersensitivity to Adenosine.

Cardiovascular: Facial flushing, headache, sweating, palpitations, chest discomfort, and hypotension.
Respiratory: Shortness of breath, dyspnea, chest pressure, hyperventilation, and a sensation of head pressure.

Central Nervous System: Lightheadedness, dizziness, tingling in the arms, numbness, apprehension, blurred vision, burning sensations, heaviness in the arms, and neck or back pain.

Gastrointestinal: Nausea, metallic taste, throat tightness, and groin pressure. Post-marketing reports have included prolonged asystole, ventricular tachycardia, ventricular fibrillation, transient increases in blood pressure, bradycardia, hypotension, atrial fibrillation, and bronchospasm associated with Adenosine use.

US FDA pregnancy category C. Animal studies have demonstrated adverse effects on the fetus, and there are no adequate, well-controlled studies in humans. However, potential benefits may justify the use of Adenosine in pregnant women despite potential risks.

Adenosine has a very short half-life (less than 10 seconds), so adverse effects are usually brief and self-limiting. Management of prolonged adverse reactions should be individualized and focused on the specific symptoms. Methylxanthines, such as caffeine and theophylline, act as competitive antagonists of adenosine.

Paroxysmal supraventricular tachycardia (PSVT)

Store in a cool, dry place, protected from light. Keep out of reach of children. Do not refrigerate, as crystallization may occur. If crystals form, they should be dissolved by warming to room temperature. Ensure the solution is clear before use.