ADENOSINE
(a-den'o-sin)
Adenocard, Adenoscan
Classifications: cardiovascular agent; antiarrhythmic
Pregnancy Category: C

Availability

3 mg/mL in 2, 5, and 30 mL vials

Actions

Slows conduction through the atrioventricular (AV) and sinoatrial (SA) nodes. Can interrupt the reentry pathways through the AV node. Depresses left ventricular function, but effect is transient due to short half-life.

Therapeutic Effects

Restores normal sinus rhythm in patients with paroxysmal supraventricular tachycardia.

Uses

Conversion to sinus rhythm of paroxysmal supraventricular tachycardia (PSVT) including PSVT associated with accessory bypass tracts (Wolff-Parkinson-White syndrome). "Chemical" thallium stress test.

Unlabeled Uses

Afterload-reducing agent in low-output states; to prevent graft occlusion following aortocoronary bypass surgery; to produce controlled hypotension during cerebral aneurysm surgery.

Contraindications

AV block, preexisting second- and third-degree heart block or sick sinus rhythm without pacemaker, since a heart block may result. Also contraindicated in atrial flutter, atrial fibrillation, and ventricular tachycardia because the drug is ineffective.

Cautious Use

Asthmatics, pregnancy (category C), hepatic and renal failure.

Route & Dosage

Supraventricular Tachycardia
Adult: IV 6 mg rapid IV bolus (over 1–2 s); may repeat in 1–2 min with 12 mg IV push, 2 times (total of 3 doses with max: 12 mg dose)
Neonate/Infant/Child: IV 0.05 mg/kg; may increase dose by 0.05 mg/kg q2 min (max: 0.25 mg/kg/dose or 12 mg/dose)

Stress Thallium Test
Adult: IV 140 mcg/kg/min x 6 min (max: 0.84 mg/kg total dose)

Administration

Intravenous

Make sure solution is clear at time of use.
Discard unused portion (contains no preservatives).

PREPARE: Direct: No dilution is required.

ADMINISTER: Direct: Administer directly into vein as a rapid bolus over 1–2 s. If given by IV line, administer as proximally as possible, and follow with a rapid saline flush.

Note: If high-level block develops after one dose, do not repeat dose.

Store at room temperature 15°–30° C (59°–86° F). Do not refrigerate, as crystallization may occur. If crystals do form, dissolve by warming to room temperature.

Adverse Effects (1%)

CNS: Headache, lightheadedness, dizziness, tingling in arms (from IV infusion), apprehension, blurred vision, burning sensation (from IV infusion). CV: Transient facial flushing, sweating, palpitations, chest pain, atrial fibrillation or flutter. Respiratory: Shortness of breath, transient dyspnea, chest pressure. GI: Nausea, metallic taste, tightness in throat. Other: Irritability in children.

Interactions

Drug: Dipyridamole can potentiate the effects of adenosine; theophylline will block the electrophysiologic effects of adenosine; carbamazepine may increase risk of heart block.

Pharmacokinetics

Absorption: Rapid uptake by erythrocytes and vascular endothelial cells after IV administration. Onset: 20–30 s. Metabolism: Rapid uptake into cells; degraded by deamination to inosine, hypoxanthine, and adenosine monophosphate. Elimination: Route of elimination unknown. Half-Life: 10 s.

Nursing Implications

Assessment & Drug Effects

Monitor for S&S of bronchospasm in asthma patients. Notify physician immediately.
Use a hemodynamic monitoring system during administration; monitor BP and heart rate and rhythm continuously for several minutes after administration.
Note: Adverse effects are generally self-limiting due to short half-life (10 s).
Note: At the time of conversion to normal sinus rhythm, PVCs, PACs, sinus bradycardia, and sinus tachycardia, as well as various degrees of AV block, are seen on the ECG. These usually last only a few seconds and resolve without intervention.

Patient & Family Education

Note: Flushing may occur along with a feeling of warmth as drug is injected.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug