DrugindexOnline^{2nd edition}

Pronouncation: (ah-DEN-oh-seen)
Class: Antiarrhythmic agent, In vivo diagnostic aid

Trade Names:
Adenocard
- Injection 3 mg/mL

Trade Names:
Adenoscan
- Injection 3 mg/mL

Mechanism of Action

Pharmacology

Slows conduction through atrioventricular (AV) node; can interrupt reentry pathways through AV node and restore normal sinus rhythm.

Pharmacokinetics

Distribution

Rapidly cleared from circulation via cellular uptake, primarily by erythrocytes and vascular endothelial cells.

Metabolism

Rapidly metabolized intracellularly to adenosine monophosphate or inosine. Inosine is ultimately degraded to uric acid.

Elimination

Extracellular adenosine has a t _½ of less than 10 sec in whole blood.

Indications and Usage

Conversion to sinus rhythm of paroxysmal supraventricular tachycardia (PSVT), including that associated with Wolff-Parkinson-White syndrome.

Unlabeled Uses

Noninvasive assessment of patients with suspected coronary artery disease in conjunction with thallium tomography. Used with BCNU for treatment of brain tumors.

Contraindications

Second- or third-degree AV block or sick sinus syndrome (except in patients with functioning artificial pacemaker); atrial flutter; atrial fibrillation; ventricular tachycardia.

Dosage and Administration

Initial dose (adults)

IV 6 mg as rapid IV bolus (over 1 to 2 sec).

Repeat administration (adults)

If first dose does not eliminate PSVT within 1 to 2 min, give 12 mg as rapid IV bolus; 12 mg dose may be repeated a second time if necessary. Doses over 12 mg are not recommended.

General Advice

• Administer either directly into vein or, if given into IV line, in most proximal IV line and follow with rapid saline solution flush.
• Do not administer if solution is cloudy or if sediment is present.
• Discard unused portion.

Storage/Stability

Store at room temperature. Do not refrigerate because crystallization may occur. If crystallization has occurred, dissolve crystals by warming to room temperature.

Drug Interactions

Caffeine, theophylline

Antagonize effects of adenosine; larger doses of adenosine may be needed.

Carbamazepine

May produce higher degrees of heart block.

Dipyridamole

Potentiates effects of adenosine; smaller doses may be adequate.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Facial flushing; headache; chest pain; hypotension.

CNS

Lightheadedness, dizziness, tingling in arms; numbness.

GI

Nausea.

Respiratory

Dyspnea; shortness of breath; chest pressure.

Precautions

Monitor BP/Cardiac rhythm Monitor BP and cardiac rhythm during and after administration. Transient asystole Monitor for transient asystole, which may develop during administration.

Pregnancy

Category C .

Lactation

Undetermined.

Arrhythmias

At time of conversion to normal sinus rhythm, new arrhythmias may appear on ECG; these are usually self-limiting.

Asthma

Adenosine may cause bronchoconstriction.

Heart block

Drug may produce short-lasting heart block. Patients in whom high-level heart block (eg, third-degree) develops after one dose should not receive repeat doses.

Patient Information

• Inform patient to report the following symptoms to health care provider: facial flushing, headache, shortness of breath, chest pressure, lightheadedness, dizziness, tingling in arms, numbness or nausea.